June 19, 2018 | Author: Anonymous | Category: Social Science, Law
Share Embed Donate


Short Description

Download ...

Description

GREATER MANCHESTER FOOD LIAISON GROUP LANCASHIRE FOOD OFFICER GROUP AND WEST YORKSHIRE PRINCIPAL FOOD OFFICER GROUP

Guidance Notes for On-Farm Pasteurisers

Produced by Sandra Bailey Rebecca Ingham Jim Livesey Garry Pearson Allan Watson

Environmental Health Officer Environmental Health Officer Public Protection Manager Senior Environmental Health Officer Food Safety Manager

Oldham MBC. Bradford MDC Hyndburn BC. Kirklees MC Rochdale MBC.

Contents Page 3

Introduction

4

Registration and Approval of premises 1

Commissioning of Pasteurisers 1.1 1.2 1.3 1.4

1.5 1.6 2

2.4

2.5 2.6 2.7 2.8

11 11 11 12 12 12 12 12 12 12 13 13 13 14 14

Pre-use Disinfection Cleaning Churns

15 15 15

Cream Separator Pre-use Disinfection and Operation 4.1 4.2

5

General Information Cleaning, Inspection and Disinfection of Filters Pre-use Disinfection and Start-up Procedure for Pasteuriser 2.3.1 Hot Start Up 2.3.2 Cold Start Up 2.3.3 Cleaning of Flow Diversion Valve Unit 2.3.4 Flow Diversion Valve Test Other Start-up Checks 2.4.1 Fitting/ Setting of Flow Restrictor 2.4.2 Visual Inspection of Pasteuriser 2.4.3 Flow Rate Test Operation of the Pasteuriser Pasteuriser Cleaning Cleaning Records Acid De-scale

Pasteurised Bulk Milk Tanks and Churns 3.1 3.2 3.3

4

5 5 5 5 5 7 7 7 8 8 9 9 9 9 10 10 10

Cleaning and Operating Procedures 2.1 2.2 2.3

3

Introduction Documentation Training Pre-production Testing 1.4.1 Flow Rate 1.4.2 Holding Time Test 1.4.3 Calibration of Thermometers and Temperature Recorders 1.4.4 Operating Temperature of the Pasteuriser 1.4.5 Positioning of the Flow Diversion Valve 1.4.6 Flow Diversion Valve Check 1.4.7 Heat Exchanger Integrity 1.4.8 Volume of Liquid in the Plant 1.4.9 Pressure Checks 1.4.10 Ancillary Equipment 1.4.11 End Product Testing on Completion of Commissioning Routine Maintenance and Calibration of the Pasteuriser Routine Maintenance of Other Dairy Machine

Disinfection of the Cream Separator Cleaning of the Cream Separator

16 16

Homogeniser Pre-use Disinfection and Operation 5.1 5.2 5.3

General Information Pre-use Disinfection Cleaning and Operation

17 17 17

- 1 -

Contents (continued) 6

Bottle Filling Machines 6.1

6.2 7

8.3 8.4 8.5 8.6

General Information Pre-use Checks and Disinfection of the Bottle Washer Operation and Cleaning of the Bottle Washer Cleaning of Milk Bottle Crates

20 20 20 21

General Layout and Workflow Structural Requirements 8.2.1 Floors 8.2.2 Walls 8.2.3 Ceilings 8.2.4 Doors/ Windows 8.2.5 Ventilation 8.2.6 Lighting 8.2.7 Hand-washing Facilities 8.2.8 Equipment/ Installations 8.2.9 Protective Clothing/Changing Facilities 8.2.10 Storage of Cleaning Equipment and Materials Bottles and Containers Equipment Water Supply Pest Control

22 22 22 22 23 23 23 23 23 24 24 25 25 26 26 27

Sampling 9.1 9.2 9.3

10

18 18 18 18 19

Structure and Equipment 8.1 8.2

9

Pre-use Disinfection and Operation 6.1.1 Disinfection with Cold Chemical Solution 6.1.2 Disinfection with Hot Water 6.1.3 Disinfection with Steam Bottle Filler Cleaning

Bottle Washing 7.1 7.2 7.3 7.4

8

Page

Sampling of raw milk Sampling of finished products Submission of samples/Unsatisfactory results

28 28 28

Pasteurising Equipment 10.1 10.2 10.3 10.4 10.5

The Pasteurisation Process Schematic Diagram of a Pasteuriser showing Heat Exchanger Regeneration Diagram of the Relevant Parts of a Typical Small-Scale Pasteurising Unit Components of a Pasteurisation Unit 10.5.1 Balance Tank and Float 10.5.2 Pump 10.5.3 Flow Controller 10.5.4 Heat Exchanger 10.5.5 Holding Tube 10.5.6 Temperature sensor 10.5.7 Flow Diversion Valve 10.5.8 Control Panel

References Appendix A

29 29 29 30 30 30 30 31 31 31 31 31 32 33

Pasteuriser Performance Report

- 2 -

34

INTRODUCTION

This guidance document is intended for the use of food safety officers involved in the approval, audit and inspection of High Temperature Short Time (HTST) pasteurisation plants in on-farm dairies. The document contains advice on good practice that is accepted by the Lancashire Food Officer Group, the Greater Manchester Food Liaison Group and the West Yorkshire Principal Food Officer Group. The Guide should be used in conjunction with the “On-farm Dairy Premises Inspection Sheet” produced by the above Groups. Additional information on routine sampling is contained in the document: “Guidance Note for Sampling and Examination of Milk and Cream” issued by Food and Environmental Microbiology Services, North West Laboratory, Preston.

- 3 -

APPROVAL & REGISTRATION OF PREMISES

On-farm dairies may require Approval in accordance with EC Regulation 853/2004. Detailed information on the Approval process and premises and the exemptions contained in the regulations is given in the Code of Practice and Practice Guidance issued by the Food Standards Agency. Premises requiring Approval To gain approval under EC Regulation 853/2004 the Food Business Operator must comply with the requirements of the relevant Regulations and in particular: Regulation EC 852/2004: on the hygiene of foodstuffs Regulation EC 853/2004: laying down specific hygiene rules for food of animal origin, Article 4 Registration and Approval of establishments

An application for Approval must be submitted using the appropriate form as specified in Annex A11.1 of the Food Standards Agency Practice Guidance (Application for Approval of a food business establishment subject to Approval under Regulation EC 853/2004) and must include all of the information detailed in Part 8 of the form (Information and documentation). Premises exempt from Approval Premises which are exempt from Approval must be registered with the Local Authority and must comply with the requirements of Regulation EC 852/2004: on the hygiene of foodstuffs

Only when the premises have satisfied the above provisions and the officer is satisfied that the dairy plant can be operated safely following pre-use commissioning and testing should milk be processed for sale. It is recommended that the Food Business Operator should obtain assistance from a suitably experienced consultant.

- 4 -

1

COMMISSIONING OF PASTEURISERS

1.1

Introduction The equipment should be installed by a reputable, competent dairy engineer, who, upon completion of the installation and testing of all the plant, should produce a Pasteuriser Performance Report (Appendix A). The testing should take account of the manufacturers specifications. It is recommended that the dairy engineer is met on site by the Food Business Operator and the Local Authority officer, who should satisfy themselves that the testing and installation has been undertaken correctly. The Food Business Operator should be encouraged to provide the dairy engineer with details of the tests to be carried out, in advance of the visit. The operator/ officer must ensure that the engineer has the skills necessary to carry out the tests, and to ensure that the equipment required to undertake the tests is brought to the dairy. (N.B. 1.2.2 Holding Time Test)

1.2

Documentation The food business operator must put in place and maintain HACCP based procedures to comply with Article 5 of EC 852/2004. These must be appropriate to the size of the business and must include suitable records. The documentation should cover the operation of the equipment, detailed cleaning procedures and arrangements for the withdrawal of products where food is not in compliance with food safety requirements. It is strongly recommended that the Food Business Operator should contact a dairy hygiene consultant, who can assist in the production of these documented procedures.

1.3

Training The person within the business who is responsible for the implementation and maintenance of the written procedures detailed above, must have received suitable training on their operation and maintenance. This may be by attendance at a “formal training course” or in the form of “one-to–one” training provided by a consultant. In addition, all other food handlers/ operatives must be trained supervised and/ or instructed in food hygiene matters appropriate to their role. It is recommended that training should be at least six hours long. A.D.A.S. offer a suitable training course which will satisfy these requirements.

1.4

Pre-Production Testing Initial pre-production testing should be carried out using water. Only when these checks have been carried out satisfactorily should a test with milk be conducted. 1.4.1 Flow Rate Each pasteuriser is designed by the manufacturer to process a quantity of milk over a given period, this is known as the flow rate. If the flow rate is too great milk will pass through the holding tube too rapidly and, although the milk may reach 72 oC, it may not be held at this temperature for the required 15 seconds, resulting in under pasteurisation. - 5 -

If the flow rate is too slow, this may cause the milk to be in contact with the heat exchange plates for too long, resulting in the milk being over heated and giving rise to caramelisation of the milk. In addition, slow flow rates can lead to milk deposit forming on the plates thereby reducing their efficiency and leading to cleaning problems. (The manufacturer or the installer should be able to provide details of the flow rate). The flow rate can be calculated, by measuring the time taken to fill a 10-gallon container, (i.e. a milk churn) with the pasteuriser operating on the “processing” setting. This should be done with water running through the machine to prevent wastage of milk. The following calculation will give the flow rate: 60 X 10 = Flow rate (gallons/ hour) Time in minutes Examples of flow rates are given below; Mins to fill a 10 gallon churn 5.45 3.87 3.00 2.00 1.35

Flow Rate: Gals / hr 110 155 200 300 444

Flow Rate: Litres / hr 500 700 900 1350 2000

Most pasteurisers have a flow restrictor (flow controller) to reduce pressure from the milk pump and ensure that the flow rate through the pasteuriser results in the correct holding time. With some units, the flow restrictor is removed during cleaning to increase the flow rate and turbulence of the cleaning fluid and improve cleaning. It is essential that it is reinstalled before processing begins as failure to do so would result in an increased flow rate an inadequate holding time and underpasteurisation of the milk. This is a common cause of phosphatase failure. Similarly, where the flow rate is adjusted by a valve, it is essential that the valve is correctly set before pasteurisation begins. Where a separator or homogeniser is being used, an additional flow restrictor may be required at the take-off point. Again, this is required to prevent an increase in flow rate which would lead to a reduction in holding time and underpasteurisation of the milk. Where the pasteuriser is fitted with a filter, this must be cleaned/ replaced regularly as debris can cause a blockage resulting in a reduced flow rate. Flow rate should be checked (a) When processing whole milk only (b) When Homogenising, (c) When separating.

- 6 -

1.4.2 Holding-Time Test A methylene blue dye test, (or other approved method) must be carried out to ensure that it takes at least 15 seconds for the liquid to flow through the holding tube. This involves introducing the dye at a point close to the start to the holding tube and, using a stopwatch, to monitor the time it takes for the dye to show at a sample point at the end of the holding tube. A specialist engineer using approved equipment will be required to conduct this test. 1.4.3 Calibration of Thermometers and Temperature Recorders In order to comply with Article 5 of EC 852/2004: a)

There should be indicating thermometers to monitor the temperature of milk at the end of the holding tube and also at the end of the cooling section.

b)

Pasteurisers must be fitted with a thermograph to keep a permanent record of the following information:  A record of the temperature of milk at the end of the holding tube, (usually a red pen);  A record of the temperature of milk after the cold section, (usually a blue pen); and  A record of when the flow diversion valve has been activated, often known as the event pen, (usually a green pen).

The recording equipment should be checked to ensure that it leaves a clear trace on the chart. Where pens are used, it is good practice for the dairy operator to have a spare set of pens available so that they can be changed over as soon as the trace becomes faint. All monitoring thermometers and thermograph recorders should be calibrated, by a competent person, to ensure their accuracy. If the thermometers and thermographs are not accurate it will not be possible to ensure that the milk is achieving 72oC at the end of the holding tube, and 6oC or below at the end of the cold section. All indicating thermometers and thermographs should be rechecked and calibrated on an annual basis or at such frequency prescribed by the manufacturer. All calibration certificates must be kept and made available on request during an inspection. 1.4.4 Operating Temperature of the Pasteuriser To provide a margin of safety, the operating temperature of the pasteuriser should normally be set at 73oC. It is recommended that the temperature of incoming raw milk should be at a constant temperature but should never be above 5oC. If the milk is too cold, i.e. 1oC then this may require too much energy from regeneration and heater sections and, consequently, the milk will not reach pasteurisation temperatures at the holding tube and the flow diversion valve will be activated. If the temperature of the incoming milk is too warm, pasteurised milk on its return from the holding tube will not be cooled sufficiently within the regeneration section. This may lead to the growth of bacteria.

- 7 -

1.4.5 Positioning of the Flow Diversion Valve. The flow diversion valve must be situated at the end of the holding tube. If the valve is fitted elsewhere, e.g. at the end of the heat exchanger, then, in the event of milk not reaching the necessary temperature at the end of the holding tube, under-processed milk will contaminate the internal surfaces of the regeneration and cold sections of the heat exchanger. When the temperature rises, and the flow diversion valve opens, pasteurised milk may become contaminated with residues of the under-processed milk that remains in the heat exchanger following the flow diversion event. If the flow diversion valve is situated at the end of the heat exchanger, a competent dairy engineer must be used to reposition the valve at the end of the holding tube. This modification must be carried out before Approval is granted for new units. Where the above situation is identified on an operational pasteuriser, enforcement action must be taken (E.g. service of Hygiene Improvement Notice). 1.4.6 Flow Diversion Valve Test The flow diversion valve must be tested at the start of each pasteurisation run to ensure that it will operate if the milk leaving the holding tube falls below 72 o C. The test should be taken during the warm up cycle while the unit is filled with water, with the pasteuriser at operating temperature and the unit switched to “automatic”/ ”processing”. The temperature of the pasteuriser should be allowed to fall by turning off the hot water pump, turning off the hot water heater or operating a current cut-out switch. Observation of the hot indicating thermometer should be made to determine the temperature at which the flow diversion valve operates, and the temperature noted must be recorded. The flow diversion valve test will also allow the correct positioning of the flow diversion pointer on the rotary type thermograph. This pointer may be disturbed during replacement of the thermograph chart and frequently does not correlate with the scale on the chart. Therefore, the thermograph hot indicator (red pen) should not be relied upon for this check as the needle is often disturbed when the chart is replaced. The flow diversion valve should be set to operate at least 0.5 o C above the minimum legally required pasteurising temperature in order to provide a safety margin. Alfa Laval machines may need to have a heater cut-out switch fitted which will allow the heater to be turned off to allow the temperature of the water to fall naturally and an accurate test of the temperature of activation of the flow diversion valve to be performed. The use of a homogeniser can cause problems with flow diversion events. The physical energy generated during homogenisation can increase the temperature of the milk by 4 - 6 oC. To compensate for this, the temperature of the heating section needs to be reduced to prevent the milk from over heating. If the temperature of the heating section is not increased again when the homogeniser is turned off, this will lead to the milk temperature falling below 72 o C and the flow diversion valve operating.

- 8 -

1.4.7 Heat Exchanger Integrity Manufacturing problems, use of incorrect cleaning products, abuse by the operator, or damage during installation can result in defects in heat exchange plates or the gaskets between them. If any of the plates or gaskets in the regeneration section are damaged, raw milk can contaminate the pasteurised milk at the opposite side of the plate. Milk pumps are positioned at the entry point of the pasteuriser and push the milk through the equipment. Therefore, the pressure is always higher in the inward (raw milk) side. Any defect in a heat exchanger plate in the regeneration section is likely to result in raw milk being forced through from the inward side to the outward side and contaminating the pasteurised milk. Where phosphatase failures occur, if there are intermittent failures or where results show adverse trends (an increase in phosphatase levels over a period of time) tests to check the integrity of the heat exchanger unit must be considered. These should only be carried out after the pasteurising temperature and holding time/ flow rate have been checked. There are a number of specialist companies which carry out plate testing, to detect faults using differing methods. These include: conductivity testing and the use of helium gas with the plates in situ, and the traditional method of inspection which involves splitting the plate banks to allow a physical examination of the individual plates using a “light box” or by painting them with a dye solution. Whenever the heat exchanger is dismantled and rebuilt, it is recommended that samples should be taken from a minimum of 3 successive batches of milk and submitted to the laboratory for phosphatase testing. Samples should be taken from the beginning, middle and end of a production run lasting not less than 30 minutes. 1.4.8 Volume of Liquid in the Plant The volume of liquid in the plant needs to be established to ensure that the correct concentrations of cleaning and disinfection chemicals are used. Most cleaning chemical manufacturers produce product data sheets, which specify a dose rate per litre of fluid. “Under dosing” may lead to ineffective cleaning and disinfection whilst “over-dosing” may cause damage to the plant or lead to difficulties in rinsing the plant effectively. 1.4.9 Pressure Checks If the pasteuriser has a pressure gauge, the Food Business Operator must be aware of the correct operating pressure for the machine. Falling pressure may indicate a problem with the pump, flow restrictor, filter or a build up on the heat exchange plates. 1.4.10 Ancillary Equipment Cream separators and homogenisers must be compatible with the flow rate of the pasteuriser. If the ancillary pieces of equipment have a greater flow rate, they may create a negative pressure drawing the milk through the holding tube at an increased rate leading to a reduced holding time and under pasteurisation. Flow diversion may not occur with an increased flow rate as the temperature at the hot sensor, located at the end of the holding tube, may be above 72 oC. In many on-farm dairies, whole milk is separated to produce skimmed milk and cream. To do this, warm milk is taken from the pasteuriser part way through the process, as warm milk separates more effectively than cold milk which has left - 9 -

the unit. It is essential that the “take off” point from the pasteuriser is on the outward side of the machine i.e. after the holding tube so that pasteurised milk is separated. If the cream take-off is positioned on the inward side of the regeneration section this will result in the production of pasteurised skimmed milk, (providing the skimmed milk is returned to the regeneration section after skimming), but raw cream, and a separate cream pasteuriser will be required. 1.4.11 End Product Testing on Completion of Commissioning When all of the above checks have been completed using water, a preproduction test run with milk should be carried out. It is recommended that the test run should be for not less than 30 minutes. Samples from the start, middle, and end of the process run for all types of milk produced, (whole milk, semiskimmed, skimmed milk), and cream, in all types of finished product containers, should be taken for phosphatase and enterobacteriaceae testing. The operator should be informed that this pre-production run is for test purposes only. No processed milk may be sold from the new premises until all test results have been received and are satisfactory, and the Approval Number has been issued. [Note: Contact should be made with the testing laboratory to arrange for the testing of the samples prior to obtaining them. A charge may be made for undertaking these tests which should be borne by the Food Business Operator.] 1.5

Routine Maintenance and Calibration of the Pasteuriser A service contract should be set up with a reputable dairy engineer to carry out the checks detailed on the Pasteuriser Performance Report (see Appendix A), at least once every 12 months. Ideally, in the first year of the contract, consideration should be given to arranging for the dairy engineer to check all instruments after one month, followed by a full service after 6 months. This should include all of the checks detailed on the Pasteuriser Performance Report. An external visual examination of the heat exchangers should be made. Signs of leaking milk may indicate the need for new gaskets. Replacement of plates and gaskets should be carried out at the frequency advised by the competent service engineer. The service engineer should have regard to the age, amount of use the machine has had and any additional factors which may necessitate the early replacement of plates, gaskets or other components. Homogenisers can cause additional stresses leading to components wearing out at a faster rate. The service engineer should also have regard to the manufacturer recommendations as to when components should be replaced. Opening of the pasteuriser heat exchanger plates by the dairy Food Business Operator must be discouraged as damage can occur whilst the plates are being repositioned and the plate pack re-tightened. In particular “over-tightening” of the heat exchanger unit can cause serious damage to the heat exchanger plates. Adjustments must only be carried out by a competent engineer.

1.6

Routine Maintenance of Other Dairy Equipment Other plant should be serviced in accordance with the manufacturer instructions. Should these be unavailable then the engineer should be consulted as to the necessary servicing intervals and preventative maintenance.

- 10 -

2

CLEANING AND OPERATING PROCEDURES

2.1

General Information All equipment, containers and pipework which come into contact with dairy products must be cleaned and, if necessary, disinfected according to a cleaning programme based on hazard analysis principles. It is essential that the correct chemicals are used, in the right concentrations, at the correct temperatures, and for the contact times specified by the manufacturer of the cleaning and disinfection chemicals. It is essential that the cleaning and disinfection chemicals used are appropriate for the chemical composition of the water at the premises as some chemicals are formulated for use specifically in hard or soft water areas. Cleaning procedures must take into account the plant used, its layout, facilities and the cleaning chemicals used by the Food Business Operator. They should include a stepby-step guide how to pre-disinfect, use and clean and disinfect all plant and equipment in the dairy. For easy reference, cleaning procedures can be laminated and displayed behind the piece of equipment to which it relates. If followed correctly these schedules are usually effective. Problems occur when the Food Business Operator deviates from the schedules or uses a new cleaning product, which requires a different dose rate or time/ temperature combination to the chemical used previously. Food Business Operators should review their cleaning schedules regularly, particularly after any change in cleaning products, and amend them as necessary.

2.2

Cleaning, Inspection and Disinfection of Filters Filters may be either a reusable mesh gauze or a disposable cloth/ paper unit. Where fitted, they must be cleaned, inspected, and disinfected prior to operation of the unit.

2.3

Pre-use Disinfection and Start-up Procedure Although pasteurisers will normally be cleaned after use, they must also be disinfected immediately before the next production run. The purpose of this is to reduce the levels of any bacteria which may have survived the cleaning process to a safe level. The most common methods are either by hot water (hot start up), or by the use of a chemical solution (cold start up). The preferred method is using hot water, however, in some units the heating unit is not capable of raising the temperature of the water throughout the whole of unit to the required temperature so a cold start-up is used. Prior to disinfection, the plant must be fully assembled and the thermograph recorders should be operating. A new thermograph chart should be inserted, if necessary, dated and signed by the Food Business Operator. Air vents if fitted (usually at the top of the holding tube), should be opened to release any trapped air and to ensure the thorough wetting of all internal surfaces. These vents should be closed when liquid is running freely from them. - 11 -

During pre-use disinfection, the hot water or cold chemical solution from the pasteuriser, may be used to disinfect ancillary equipment such as the homogeniser or separator. In the case of a cold start up any additional amount of liquid involved should be considered when calculating the strength of the disinfectant solution 2.3.1 Hot Start-up To ensure adequate disinfection, a hot start-up requires a minimum temperature of 75 oC, throughout all sections of the plant, for not less than 15 minutes. It is imperative that all of the heat-exchanger plates reach this temperature and not just the hot holding section. To achieve this, it is necessary to turn off the supply of cold water/ coolant to the cooling section of the heat exchanger unit. The temperature can be checked using the cold pen on the thermograph, or the cold end thermometer. If difficulties are encountered when attempting to raise and maintain the temperature throughout the equipment, steam can be added to the balance tank to boost the temperature, if available. If there are long sections of pipe work after the outlet from the pasteuriser then temperature may be lost resulting in ineffective disinfection. In this case, a cold start up may be preferred. 2.3.2 Cold Start-up The cold start up method requires the cold circulation of hypochlorite at a strength of 100ppm for at least 10 but no longer than 20 minutes. Hot water must never be used with hypochlorite as it has a corrosive action on the stainless steel heat exchange plates. Only fresh preparations of hypochlorite should be used and the product must be within its manufacturer shelf life to ensure the correct concentration of available chlorine for disinfection. Before milk is introduced, the plant must be thoroughly rinsed using cold clean water in order to remove the residues of the disinfectant. 2.3.3 Cleaning of the Flow Diversion Valve During the pre use disinfection, the flow diversion switch should be manually activated frequently, in order to clean the valve, seating and associated pipe work. 2.4

Other Start-up checks 2.4.1 Fitting/ Setting of the Flow Restrictor. A check must be made that the flow restrictors are in place or set correctly. 2.4.2 Visual Inspection of the Pasteuriser If the gaskets are leaking then this indicates that they may need to be replaced. A dairy engineer should be contacted without delay. Tightening of the plate pack should be discouraged as over tightening can result in distortion or damage to the plates.

- 12 -

2.4.3 Flow Rate Test A flow rate test should form part of the annual maintenance check. In addition, it should be checked at least every month by the Food Business Operator and a record of the result made (see Para 1.4.1). Where the flow rate is found to be above that stated in the Pasteuriser Performance Report (see Appendix A), the equipment should not be used until it has be examined by a competent engineer. 2.5

Operation of the Pasteuriser Once pre-use disinfection is complete, and the equipment is full of clean water, the heater elements should be switched on and water circulated around the system until the normal operating temperature is reached. Before milk is introduced, the flow diversion valve must be tested as detailed in 1.4.6. The thermograph and indicating thermometer should be checked to ensure that the flow diversion valve is operating at the correct temperature. The thermograph should then be signed and dated by the operator. Where necessary, adjustments should be made to the flow diversion pen, so that it operates at the correct temperature. All thermographs must have sufficient chart space for the full days production run. They must not be allowed to ‘over write’, as an accurate record will not be produced of the processing. The hot and cold temperatures on the thermograph must be checked and verified using the indicating thermometers. The pressure gauges, if fitted, should also be checked. When the temperatures have stabilised processing may begin. When milk is introduced, the first milk to show at the pasteuriser outlet will contain water. Sufficient milk must be run to waste to prevent milk for bottling becoming diluted with water. Running time must not exceed 6 hours as long running times result in milk deposits collecting on the heating surfaces leading to ineffective heat exchange and difficulties in cleaning.

2.6

Pasteuriser Cleaning following a Production Run At the end of the production run, the milk should be displaced from the equipment by running cold water through the plant. When clean water appears at the pasteuriser outlet, the flow of water should be returned to the balance tank and circulated for a period of not less than 10 minutes. If the circulating water is heavily contaminated with milk residues, the system should be refilled with clean water. Detergent should now be introduced into the plant via the balance tank and circulated within a closed circuit at 70-80oC for 20 minutes. The time, temperature and chemical strength recommended by the manufacturer must be followed. The strength of the caustic should be around 2% concentration and be added to the balance tank gradually to ensure an evenly mixed volume is circulating around the equipment. Adding all the caustic at one time could form a plug of chemical that will take a long time to disperse evenly throughout the circulating water. After long processing runs the contact time and the concentration may need to be increased. Where fitted, the flow restrictor must be removed or adjusted to increase the flow rate and improve cleaning. A flow rate of 10% above processing flow is desirable. It is essential that the volume of liquid in the equipment is known so that the correct strength of caustic required for cleaning can be calculated. For example, if the volume is - 13 -

300 litres – 6 litres of caustic will be required to give a 2% concentration, providing the caustic is supplied at 100% concentration. However, most caustic is supplied at around 33% concentration, therefore, using the previous example, three times as much must be added i.e. 18 litres, to arrive at a 2% concentration. Powdered detergent must never be introduced directly into the balance tank, it must always be pre-mixed with water in a stainless steel or plastic bucket prior to being used in the plant. If additional pipe work or ancillary equipment is cleaned in-line with the pasteuriser, then the extra volume of liquid involved should be included when calculating the concentration detergent required. The hot cleaning solution should be circulated through the pasteuriser and all interconnecting pipe work and fittings. The cleaning time should be measured from the time the fitting or pipe work at the most distant point on the pasteuriser cleaning circuit reaches over 80oC. A common mistake is to measure the cleaning time from the time the thermometer and thermograph indicate that the temperature at the end of the holding tube is at above 80oC. During circulation of the cleaning solution, the surfaces of the balance tank above the detergent level should be brushed to remove any contamination. At end of the cleaning cycle the flow diversion valve should be allowed to automatically divert on a falling temperature so that it is cleaned by circulation for a minimum of five minutes. When the cleaning cycle has been completed, the detergent solution must be flushed out with clean, cold water. 2.7

Cleaning Records Most plants, (apart from the Alfa Laval Microtherm machines), have the facility to monitor and record the times and temperatures at the hot and cold end of the pasteuriser during cleaning. The Alfa Laval Microtherm machines, however, wash using the “automatic” and the thermograph does not operate. A manual check will need to be made of the temperature of the solution returning to the wash tank. This should be recorded on a daily process sheet.

2.8

Acid de-scale With current detergent formulations acid descaling should not be necessary. Should a build up of milk deposit occur then an alternative detergent system should be considered. Checking the difference between the temperature of the hot water and that of the milk can identify a build up of ‘milk stone’ deposit on the heat exchanger plates. Normally the difference will be about 4 oC. If it is much greater than 6 oC then this would probably indicate a build up of solids on the plates making heat transfer more difficult and thus, automatically increasing the hot water temperature in compensation. In this case an acid de-scale would be needed in addition to normal cleaning. Advice from the plant manufacturer and the chemical supplier must be sought before undertaking this operation. After the acid de-scale the plant must be rinsed thoroughly with cold clean water, followed by a final weak alkaline solution, equivalent to 0.1% solution of sodium hydroxide. This will prevent damage to stainless steel plates.

- 14 -

3

PASTEURISED BULK MILK TANKS and CHURNS

3.1

Pre-use Disinfection Tanks can be disinfected using cold chemical solution, hot water, or steam. The manufacturer instructions for the cleaning and disinfection of non-metallic or aluminium tanks should be sought. If the tank is cleaned with a combined disinfectant/ detergent then pre-use disinfection will not be required, providing the tank is used immediately. If the tank is not used for a period of more than four hours, a further pre-use disinfection will be required. Chemical disinfection with hypochlorite, followed by a clean water rinse, is the most commonly used method. If a “clean-in-place” system is used then the spray ball must be suitably located to ensure the thorough wetting of the internal surfaces of the tank.

3.2

Cleaning After emptying all milk from the tank, the internal surface of the tank should be rinsed with clean cold water and the surfaces scrubbed to remove all stubborn milk residues. The tank should then be cleaned using a suitable detergent, (this is often in the form of a “pink powder”). Special attention should be paid to the inlets, outlets, gaskets and other fittings the tank may contain. Flush the tank thoroughly with clean water to remove all detergents/ disinfectant. The agitator paddle and other fittings should be removed and dismantled each time the tank is cleaned.

3.3

Churns If churns are used for storage or transport of milk the Food Business Operator should use disposable churn liners.

- 15 -

4

CREAM SEPARATOR CLEANING AND DISINFECTION

4.1

Disinfection of the Cream Separator. The separator must be disinfected immediately prior to use to reduce bacteria to a safe level and to prevent contamination of the pasteurised milk. The cream separator can be disinfected separately or in-line with the pasteuriser during a hot or cold start-up, using the hot water from the pasteuriser during the disinfection of the unit or hypochlorite solution. After disinfection with a chemical solution the machine should be rinsed using clean cold water. Care must be taken that the separator reservoir is given sufficient contact time, over all the internal surfaces, to ensure effective disinfection. (At least 10 minutes for cold start up and 15 minutes for a hot start up).

4.2

Cleaning of the Cream Separator Separators should be cleaned following the manufacturer instructions: At the completion of use, the separator should be rinsed using water at between 40 oC and 50 oC until the water runs clear. The bowl and disks must be dismantled. The disks should be scrubbed, with a nylon brush, using a mild detergent solution, (usually supplied as ‘dairy detergent’), again at 40oC - 50oC. If any “milk stone” has developed, an acid de-scale may be necessary, following the manufacturers instructions After cleaning, the components should be dried and stored in a clean place or may be left overnight in clean water prior to reassembly immediately prior to the next production run.

- 16 -

5

HOMOGENISER PRE-USE DISINFECTION AND OPERATION

5.1

General Information The instructions given by the manufacturer of the plant must be followed carefully, as the high strength stainless steel used in some units may be susceptible to corrosion. The detergent solution must be free of all undissolved particles as these may cause damage to the piston seals and homogenising valves.

5.2

Pre-use Disinfection Pre-use disinfection must be carried out immediately before the plant is used. The preferred method for disinfecting homogenisers before use is with hot water, due to potential corrosion problems of using chemical disinfection solutions. Processors may have difficulties in achieving and maintaining the required temperature due to the energy it can take to heat the large metal mass of the plant. The pressure from the homogenising valves must be released. Hot water must be circulated for at least 20 minutes after its return temperature reaches 80 oC. If there is no alternative to the use of a cold chemical solution, the advice of the manufacturer must be sought and followed rigorously.

5.3

Cleaning and Operation Following processing, the plant must be rinsed with clean cold water to remove all loose milk residues. In most cases the homogeniser is cleaned “in line” with the pasteuriser. The time, temperature and causticity combinations specified by the manufacturer of the cleaning chemical must be followed. The pressure of operation of the homogeniser should be reduced to approximately 550 kN/m2, as indicated by the pressure gauge. Following cleaning, the machine should be rinsed with clean cold water. This pre and post clean rinsing with clean cold water should be limited to approximately 3 or 4 minutes, as water is a poor lubricant, and operation of the plant with water can lead to excessive wearing of the components. If recommended by the manufacturer, the pressure gauge, homogenising valves and any standpipe pressure pulsation damper should be removed and inspected for residues. If necessary, manual cleaning with a suitable hand washing detergent or combined detergent disinfectant should be carried out at temperatures of approximately 60 oC and no lower than 45oC. The components should be thoroughly rinsed with clean cold water and the machine should be reassembled using clean hands.

- 17 -

6

BOTTLE FILLING MACHINES

6.1

Pre-use Disinfection and Operation. Before use the bottle filler must be disinfected using a hypochlorite solution, hot water, or steam. The pipelines used to pass the products to the filler should be included in this process. The manufacturer of the plant should be consulted for the best method of disinfection to use as disinfection by hot water or steam may not be suitable for all machines. Initial disinfection of the filler valves and the filler head rubbers should be carried out by immersing them in a 20 mg/ litre hypochlorite solution for 2 hours. Adding 1ml of hypochlorite to 5 litre of water can produce this concentration. The valves and rubbers must be rinsed with cold clean water. Hairline cracks in filler valves or poor welding/ soldering at the fitting point for the valves can leave fissures which can not be cleaned or disinfected effectively, resulting in samples failing to meet the legal standard. In this case, new valves or improved welding/ soldering may be needed. Pre use disinfection should be carried out as close to the time of filling as possible. 6.1.1 Disinfection with cold chemical solution The rubbers should be reassembled using clean hands. All surfaces should then be thoroughly wetted with disinfectant solution and allowed to stand for between 10 and 20 minutes. The solution should then be run through the filler valves and heads. The filler bowl, valves and heads must be rinsed with clean cold water before use and the first few bottles filled should be discarded as they may contain some of the rinse water. 6.1.2 Disinfection with hot water. The disinfected rubbers should be reassembled using clean hands. Hot water at above 75oC should be introduced into the filler bowl. Once the filler bowl is full the valves should be opened and hot water should be introduced at a rate that allows the bowl to remain full during this process. The hot water should be allowed to flow through the valves at this temperature for at least 15 minutes. 6.1.3 Disinfection with steam The disinfected rubbers must be reassembled using clean hands. Clean steam should be injected into the filler in accordance with the manufacturers instructions.

- 18 -

6.2

Bottle Filler Cleaning At the end of the production run the filler bowl should be drained and rinsed with cold water All removable fittings should be dismantled e.g. air pipes, filling rubbers, valves and these should be washed separately with a solution of detergent at 40oC - 50oC. Particular attention must be paid to valve stems. The filler bowl should be scrubbed with a detergent solution at 50oC, rinsed and reassembled using clean hands. The equipment should be left covered until pre-use disinfection shortly before the machine is used again. The cap forming die and sealing head must also be cleaned and disinfected following the manufacturers instructions. Where a vacuum system is fitted to assist with the rapid filling of the bottles by removing air, this must be cleaned and disinfected between each production run following the manufacturers instructions.

- 19 -

7

BOTTLE WASHING

7.1

General Information One of the most common causes of intermittent microbiological failure is ineffective washing and disinfection of bottles, or bottles being washed too far in advance of being filled. Some small on-farm processors may have bottles washed off the premises, at a remote site owned by a larger processor. The smaller processor has no control over the washing and disinfection of the bottles. After cleaning, they are transported to the dairy, on occasions ineffectively protected from contamination from the environment. This practice, should be discouraged. Bottles must be washed in accordance with the instructions supplied by the bottlewasher manufacturer using chemicals for the appropriate time, temperature and concentrations as recommended by the chemical manufacturer.

7.2

Pre-use Checks and Disinfection of a Bottle Washer. The bottle washer should be cleaned and disinfected daily. All jet manifolds must be brushed to remove deposits and the jets checked to ensure that they are not obstructed. Where necessary they can be cleared using a piece of fine wire. The rinse tank should be emptied and hosed out daily using clean cold water.

7.3

Operation and Cleaning of a Bottle Washer. Bottles should be inspected before they are put through the bottle washer. Grossly soiled bottles should be removed and disposed of carefully. Detergent solutions should be totally changed or topped up at regular intervals, to maintain the concentration specified by the manufacturer of the unit or chemical supplier. When the detergent solution is changed the tanks should be thoroughly cleaned and hosed out. Detergent should be added to the wash tanks and hypochlorite to the rinse tanks to achieve the manufacturer’s recommended concentrations. The manufacturer will also indicate the temperature range in which the detergent and the heat will act as a disinfectant. The temperature of the wash tanks and the concentration of the chemicals used are critical to ensure bottles are effectively cleaned and, therefore, maintain the safety of the product. Records should be kept of the operating temperature of the tanks and that the tanks have been dosed and topped up if necessary during washing. Detergent solutions will become diluted during the washing process and may require topping up to maintain the correct concentration. If the processor does not have titration facilities, automatic metering or other testing equipment, a general guide is to re dose as per the cleaning chemical manufacturer recommendations after 25 - 50 crates of bottles have been cleaned.

- 20 -

7.4

Cleaning of Milk Bottle Crates Each crate should be washed between use. Most bottle washers are ‘in crate’ washers and the crates are usually adequately washed during this process. Some bottle-washers wash the bottles out of the crate. Problems can arise when washed and disinfected bottles are left to drain ‘neck down’ in the unwashed crates, before being filled. If crates are manually cleaned, they should be scrubbed inside and out with a hot detergent solution and then rinsed with clean water.

- 21 -

8

STRUCTURE AND EQUIPMENT

8.1

General Layout and Work Flow The size of any room or rooms in any treatment or processing establishment should take account of all necessary plant and equipment, and include of sufficient space to allow persons to operate the equipment safely and hygienically. Plant and equipment should be positioned to ensure a logical, progressive flow of product through the various stages of production and processing without any risk of contamination, Sufficient storage should be provided for the following:   

8.2

Returned reusable containers (e.g. glass bottles) prior to washing; New and disposable containers and lids; Chilled finished products;

Structural Requirements 8.2.1 Floors Floors should be laid with a suitable fall to encourage self-drainage. Ideally, floors should incorporate suitably constructed and covered drainage channels that connect to a trapped foul drainage outlet. Floor finishes should be easily cleanable, non-absorbent, non-slip and resistant to impact, heat, acids and alkalis. A well-laid granolithic floor, with a smooth finished surface, will meet these requirements as will a well laid quarry tile floor however, the latter is more susceptible to impact damage. 8.2.2 Walls Walls should be free from all unnecessary projections and indentations etc. and well maintained. The wall surface must be smooth, durable, non-absorbent, easily cleanable and light coloured. The surface coating or covering will depend upon the condition of the wall surface, i.e. where the wall surface is in good condition regular painting with a proprietary paint with anti-fungicidal properties should suffice, but where the wall surface is poor, suitable cladding may be more appropriate. Where cladding is fixed care must be taken to ensure that there are no voids behind the sheets, which could provide harbourage for pests, and that all joints are effectively sealed. Pipes, conduits etc. should be securely fixed and mounted clear of wall surfaces to allow effective cleaning. Where services pass through walls they must be properly sealed to prevent entry by pests. Protection should be provided to exposed wall angles to minimise damage to the wall surfaces. Wall junctions with floors and ceilings should ideally be coved to allow easy cleaning.

- 22 -

8.2.3 Ceilings Ceilings should be free from unnecessary ledges and protrusions and well maintained. The ceiling surface should be smooth, easily cleanable and light coloured. It may be necessary to underdraw ceilings to enable a smooth surface to be achieved. Where practicable the ceiling should be insulated to prevent condensation and an access point to the ceiling void should be provided for maintenance and inspection purposes. 8.2.4 Doors/ Windows Doors and windows should be well maintained and provided with a durable, nonabsorbent, light coloured, easily cleanable surface finish. Doors should be clad internally to provide a smooth surface and fitted on both faces with non-corrodible metal kick plates to a minimum depth of 150mm (6”). Closed doors should fit closely at the base with the sill or floor surface and at the edges with the jambs, to ensure that any gap does not exceed 10mm (3/8”). All opening windows should fit tightly when closed. All and opening windows should be fitted with fine mesh screening to prevent entry by flying insects. Overlapping strip curtains should be fitted to external doors. Ideally screening should be removable for cleaning purposes. Internal window sills should ideally be sloped at an angle of approximately 30o to prevent items being stored on them and assist with cleaning. 8.2.5 Ventilation Adequate ventilation must be provided. Mechanical extraction ventilation with inlets sited above major steam sources e.g. bottle washers, should be installed. Consideration should be given to the siting of ventilation outlets in relation to the position of opening windows and doors to ensure ‘short circuiting’ of incoming air does not occur. 8.2.6 Lighting Adequate artificial lighting must be provided, for example, by means of fluorescent lights. Ideally these should be fitted with diffusers to prevent products becoming contaminated in the event of a bulb becoming damaged. 8.2.7

Hand washing facilities An adequate number of wash hand basins should be provided in processing areas in locations which are easily accessible for food handlers and also in the sanitary accommodation. These must be: 

supplied with hot and cold water (or pre-mixed water at a suitable temperature) from taps which are preferably not hand or arm operated;



provided with sufficient supplies of bactericidal soap;



drained by carrying the water directly in a pipe or a suitably constructed and covered floor drainage channel connected to a trapped foul drainage outlet - 23 -

fitted with a suitable grating or cover. Ideally hand wash facilities should not drain directly onto the floor surface; 

8.2.8

provided with disposable paper towels as a hygienic means of drying hands. A bin with a suitable lid must be provided for used paper towels. This must be emptied regularly.

Equipment/ Installations Equipment or installations etc. which are cleaned-in-place (C.I.P) should always be cleaned in accordance with the manufacturers’ instructions; e.g. with regard to quantity of cleaning material, temperature to be attained during cleaning, circulation times, etc. Suitable deep sinks or wash troughs should also be provided, capable of accommodating the largest pieces of equipment which require washing by hand. All sinks/ wash troughs must be provided with a hot and cold water supply and sufficient supplies of suitable detergents, disinfectants, etc. Cleaning equipment e.g. brushes, squeegees etc. should not contain any wood. In addition, separate colour coded equipment should be provided for cleaning equipment used for raw milk and for cleaning equipment used for heat-treated products. Equipment used in the milking parlour must not be cleaned in the dairy due to the risk of cross contamination. After use, all cleaning equipment should be left clean and dry and stored in a designated area of the premises. Waste water from fixed sinks should be discharged directly into a pipe or a suitably constructed and covered floor drainage channel connected to a trapped foul drainage inlet fitted with a suitable grating or cover. For all cleaning situations in the dairy industry reference should also be made to: 

BS5305 : 1984 ‘Cleaning and Disinfecting of Plant and Equipment used in the Dairying Industry’; or



BS 7771:1994 ‘Code of practice for pasteurization of milk on farms and in small dairies’

8.2.9 Protective Clothing/ Changing Facilities All staff working in the dairy must wear suitable protective clothing. This should consist of a clean washable overall, clean washable head covering capable of enclosing the hair and clean washable footwear. Any other protective clothing e.g. apron, should also be clean and washable. Protective clothing should not be worn when carrying out any other activity which is likely to introduce a risk of contamination. A person working in a milking parlour should not enter a production or processing area directly, without changing protective clothing (including footwear) and washing hands and forearms.

- 24 -

Adequate changing facilities must be provided for employees. However, by agreement with the local authority, changing and toilet facilities may be provided in the farmhouse. Where provided, changing facilities should consist of at least one room, separated from any production or processing area. The floors, walls, ceilings, doors, windows, lighting and hand-washing facilities should be of the same standard as detailed above. Toilets must be separated from the production areas by a lobby which is ventilated to the external air. Adequate natural or mechanical ventilation must be provided. 8.2.10 Storage of cleaning equipment and materials Suitable arrangements must be made for the storage of cleaning equipment. This should be in the form of a separate room or locker. The store should be outside any production or processing area, but easily accessible. Tools used for maintenance purposes etc. must not be stored in a production or processing area when not in use. 8.3

Bottles and Containers Unwashed bottles or other containers should not be stored in a production or processing area prior to cleaning. Ideally, a separate building or room close to the bottle washing equipment should be provided, for storage of unwashed bottles. The storage area should have readily cleanable surfaces and a floor, which is smooth, non-absorbent and capable of being kept clean e.g. smooth finished concrete. Bottles and other containers should be brought into the bottle washing area immediately before they are to be washed and should not pass through any production or processing areas before cleaning. In newly constructed dairies, areas which are completely separate from production and processing areas should be provided for storage and cleaning of returned bottles and containers. Washed bottles or containers should be examined after washing and stored in an inverted position, protected from the risk of contamination until required for refilling. The interval between washing and refilling should be as short as possible. Similarly, foil, foil caps, container caps and closures, labels, etc. should be stored in a closed container in a suitable store, to minimise the risk of contamination. New, unused bottles or disposable containers should, where practicable, be kept in a cool, dry store separate from any production or processing area. The store should have readily cleanable surfaces and provide protection from the risk of contamination. Bottles and containers should be stored off the floor and kept in their original packaging until required. Any remaining bottles or containers in opened packaging should be suitably covered and protected from the risk of contamination. Only the number of bottles or containers required for immediate filling should be taken into the processing/ filling area.

- 25 -

8.4

Equipment All plant, equipment or utensils intended to come into contact with milk or milk products should be: 

suitable for use with such products;



of sound construction, well maintained, clean and, as far as practicable, totally enclosed;



used for no other purpose, except the storage, production or processing of milk or milk products.

Refrigerators (including cold stores), freezers, storage areas for products, etc. should be: 

of sufficient size to accommodate maximum quantities of product requiring storage;



located correctly to ensure that the logical flow of product is not interrupted and there is no risk of contamination from raw to heat treated product e.g. in product reception area, in finished product dispatch;



well constructed, well maintained and clean;



of suitable materials e.g. corrosion resistant, smooth, durable, light coloured and easy to clean.

In addition, refrigerators (including cold stores), freezers should be: 

provided with an easily readable, calibrated indicating thermometer on the outside of the cabinet or structure which should be read and recorded at least twice daily by the Food Business Operator. Thermometers should be checked annually by a competent engineer;



capable of retaining milk and milk based products at the required temperature, (6oC or less).



fitted with flexible overlapping strips or other suitable ambient air deflection equipment in door openings, where doors are open for prolonged periods e.g. during loading.

Delivery vehicles (e.g. milk tankers) used for transporting milk or milk based products must be cleaned and disinfected after each time they are used. Where vehicles are not provided with self-cleaning mechanism suitable facilities should be provided for cleaning and disinfection. Cleaning and disinfection should take place on a suitable hard standing e.g. concrete, which should be laid with a fall to a trapped foul drainage inlet fitted with a cover or grating. Tanks should be protected from any risk of contamination following cleaning and disinfection. Vehicles should be clearly labelled “For foodstuffs only”. 8.5

Water Supply The water supply to the dairy needs to be considered in relation to its microbiological safety and chemical composition. Where the supply is a private supply (e.g. from a well spring or bore hole) or where storage tanks are used, it must be tested prior to commencement of production and then on a regular basis. In “hard-water” areas, tests

- 26 -

for hardness will need to be carried out, as this will affect the choice of cleaning and disinfection chemicals that can be used. Any tanks used for water storage must be completely covered, regularly inspected and maintained. This should include cleaning and disinfection. 8.6

Pest Control Adequate pest control procedures must be in place. These should include building construction and maintenance. Sealing all holes in walls and roofs; doors which fit tightly when closed; fitting fine mesh screens to opening windows; trapped and suitably grated drainage outlets will help to prevent entry by pests. In addition, areas on the outside of the premises must be kept tidy and clear of accumulations of rubbish, weeds, etc. A reputable pest control company should be employed to regularly monitor, and treat any infestation. Electric fly killers should be installed close to access points into any production or processing area to reduce the risks from flying insects. To minimise risks of contamination, they should be sited away from processing equipment. They should be cleaned regularly and the UV tubes changed at the manufacturers specified intervals.

- 27 -

9

SAMPLING

9.1

Sampling of Raw Milk EC 853/2004, Annex III, Section IX, sets out requirements for the sampling of raw milk. Where a Food Business Operator sells part of their production of raw milk to a wholesaler, enforcement officers should take into consideration the results of any sampling the wholesaler carries out. Similarly, the same Regulation requires Food Business Operators to ensure that raw milk is not placed on the market if it contains unsatisfactory levels of antibiotics. When considering this requirement, enforcement officers may wish to take into consideration the following: 

whether all of the milk processed within the premises is produced by cows under the control of the food business operator;



whether effective procedures are in place to control the use of antibiotics and for the monitoring of withdrawal periods; and



where milk is also sold to a wholesaler, the results of any tests carried out by them.

Enforcement Officers may wish to implement a higher priority of enforcement of this requirement where they have concerns regarding the above issues or where milk intended for pasteurisation is being purchased from a third party. 9.2

Sampling of Finished Products The Food Business Operator must put in place a sampling programme for Enterobacteriaceae, to comply with the requirements for the microbiological criteria of foodstuffs set out in EC 2073/2004. Annex 1, Chapter 2, Section 2.2.1. In addition, products must also be tested for Alkaline Phosphatase activity to ensure that they have been adequately pasteurised, as detailed in EC 1664/2006. This requires that products should be tested for Alkaline Phosphatase using the flourimetric method. The test is considered to give a negative result if it is not higher than 350mU/l.

9.3

Submission of Samples and Action in the Event of Unsatisfactory Results Sampling frequency: EC 2073/2005, Article 5 states that Food Business Operators shall determine appropriate sampling frequencies based on HACCP principles, and that these may be adapted to the nature and size of the food business, provided that the safety of the foodstuffs will not be endangered. When the Regulations came into force, the Food Standards Agency advised that sampling frequencies should not be varied from those set out in previous legislation. On this basis, it is recommended that samples should be submitted by the food business operator once per month for the tests set out in 9.2. This frequency should be subject to increase or decrease based on the results of previous samples. Samples should be submitted to suitably accredited laboratories. The documented procedures produced by the food business operator should include the action to be taken following receipt of unsatisfactory results and in particular the arrangements for the withdrawal of products where food is not in compliance with food safety requirements as required by EC 178/2002, Article 19.

- 28 -

10

PASTEURISATION

10.1

The Pasteurisation Process Pasteurisation occurs when a product is heated to the required temperature and retained there for a prescribed period of time. Different products require different time/ temperature combinations to achieve adequate pasteurisation. Milk is normally pasteurised by the High Temperature Short Time method (H.T.S.T.) using equipment which operates as a heat exchanger. The time/ temperature combination for milk is normally 72oC for a minimum period of 15 seconds. Milk is fed into the pasteuriser from a bulk milk storage tank. It is recommended that the temperature of the supply milk should be constant and about 4oC.

10.2

Schematic Diagram of a Pasteuriser showing Heat Exchanger.

Cooling Section

Milk from Holding Tube Regeneration Section Hot Water In

Chilled Water Out

To Holding Tube

Cooled Finished Milk Out

Hot Water Out

Chilled Water In

Heating Section

Raw Milk In

10.3

Regeneration The normal efficiency of the regeneration section of a heat exchanger pasteurising unit is about 90%. If milk were to be admitted to the regeneration section at 4oC and pasteurised at 74oC the temperature of the milk would have to be raised by 70oC (i.e. 74oC – 4oC = 70oC). Assuming a 90% efficiency in the regeneration section, the temperature of the milk would rise by 63oC by regeneration (i.e. 90% of 70oC). The temperature of the milk at the start of the heating section would be 63oC + 4oC = 67oC. Therefore, the heat required for pasteurisation would be 74oC – 67oC = 7oC. If the regeneration section of the pasteuriser can raise the incoming milk by 63oC then it follows that the temperature of the hot, processed milk must be reduced by the same amount. Therefore, the temperature of the milk on exit from the regeneration section must be 11oC (74oC – 63oC =11oC).

- 29 -

The milk must be cooled by a further 5oC to comply with the recommended temperature of 6oC for the finished product. If the process temperature is increased even slightly, the cooling requirement increases dramatically. Note: A 2oC rise in processing temperature increases the cooling requirements by 23% A 3oC rise in processing temperature increases the cooling requirements by 42% !!! The enzyme Lactoperoxidase is inactivated at 80oC. However, recent tests have shown that the presence of Lactoperoxidase in milk may have an antibiotic effect which reduces the number of spoilage bacteria resulting in a slightly longer shelf life. Therefore, over processing the milk and killing the enzyme may be detrimental and actually reduce the keeping quality of the milk. 10.4

Diagram Identifying the Relevant Parts of a Typical Small-Scale Pasteurising Unit Key

Part Ref:

Description

a

Raw Milk In

b

Balance Tank

c

Milk Pump

d

Flow Restrictor

e

Regeneration Section

f

Heating Section

g

Holding Tube

h

Temperature Sensor

i

Flow Diversion Valve

j

Diverted Flow

k

Normal Flow

l

Pasteurised Milk Out

10.5

m

Control Panel

n

Thermograph Chart

o

Gauges

g

m

n

o l

f

e

d k

b c

a

j

i

Components of a Pasteurisation Unit 10.5.1 Balance Tank and Float Receives raw milk and ensures a constant supply of product to ensure that the pump does not run dry. 10.5.2 Pump Supply pump should operate at aflow rate of 2.5 – 3 times that required for pasteurisation. This is required to ensure adequate cleaning of the plant after each production run.

- 30 -

h

10.5.3 Flow Controller/ Restrictor This is either a valve assembly or a restrictor device in the pump. Its function is to regulate the flow of the product through the heat exchanger during pasteurisation, to ensure adequate heating and the correct holding time. 10.5.4 Heat Exchanger A heat exchanger comprises a number of very thin stainless steel plates which are batched in ‘sets’. The number of plates in a set varies and is largely governed by the pump capacity. The larger the pump the greater number of plates in a set. The plates are sealed from each other by gaskets. Within the heat exchanger, cold milk for pasteurisation enters from one end and is pre-heated by the hot milk which has been pasteurised which passes in the oposite direction. Conversely, hot milk which has been pasteurised is cooled by cold milk entering the unit. As the efficiency of a heat exchanger is around 90%, additional heating of the milk is required before it enters the holding tube. This is provided by hot water or steam within the “hot end” of the unit. Similarly, milk leaving the pasteuriser to be bottled/ packed will require additional cooling. This is provided by chilled water or coolant (e.g. glycol) within the “cold end” of the unit. 10.5.5 Holding Tube The purpose of the holding tube is to ensure that milk which has been heated to a temperature of not less than 72oC within the heat exchanger is held at this temperature for a minimum of 15 seconds before it re-enters the heat exchanger to be cooled. The dimensions of the holding tube (length and diameter) need to be calculated in relation to the flow rate of the pastueriser. It should also have two injection points fitted to it. One where the finished product exits the heat exchanger and enters the holding tube and the other at the exit of the holding tube next to the flow diversion valve, to allow an engineer to check the holding time by measuring the length of time it takes coloured dye to pass through the tube.. 10.5.6 Temperature Sensor and Gauge The holding tube is fitted with a temperature sensor and gauge at the outlet so that the temperature of the finished product can be measured. The sensor must also be connected to the thermograph chart so that a permanent trace of the temperature of pasteurisation is made. 10.5.7 Flow Diversion Valve The purpose of the Flow Diversion Valve is to prevent milk which has not maintained the correct temperature of (72oC) for the required time of not less than 15 seconds, from leaving the pasteuriser. It is operated by the temperature sensor at the end of the Holding Tube. The valve should be positioned upright and be set at high level. Diverted product must always be passed downwards and return back to the balance tank.

- 31 -

10.5.7 Control Panel Control panel should have two ‘set points’ and one Auto/ Manual Switch. ‘Set Points’:

One set point controls the divert temperature and should be set by the installer. This set point should be secured (i.e. locked/ tagged/ sealed) and it must not be possible for the operator to alter it. The second set point controls the operating temperature of the equipment. This controls the temperature of the water and should be about three degrees above the process temperature requirements. (i.e. if process temperature is 73oC operating temperature should be set at 76oC).

Auto/ Manual Switch: When milk is being pasteurised the switch must always be set to “automatic”, so that the Flow Diversion Valve will operate if the milk has not breached the correct minimum temperature (72oC). The Manual setting is required for cleaning purposes. When the switch set to this position the Flow Diversion Valve is disabled.

- 32 -

REFERENCES

Guidance Documents A.D.A.S.

Pasteurised milk – guidelines for “on farm” milk processors: production steps and control means for assured hygienic quality. (1996)

British Standards Institute B.S.7771:

Code of practice for pasteurisation of milk on farms and in small dairies (1994)

British Standards Institute B.S.5305:

Code of practice for cleaning and disinfecting of plant and equipment used in the dairying industry (1984)

Food Standards Agency – Dairy Hygiene Inspectorate

Milk Hygiene on the Farm – A Practical Guide for Milk Producers (2006)

Legislation 1990 Chapter 16

The Food Safety Act 1990

SI 2004: No 2990

The Food Safety Act 1990 (Amendment) Regulations 2004

SI 2004: No 3279

The General Food Regulations 2004

SI 2006: No 14

Food Hygiene (England) Regulations 2006

EC 178/2002

- laying down the general principles and requirements of food law, establishing the European Food Safety Authority and laying down procedures in matters of food safety

EC 852/2004

- on the hygiene of foodstuffs

EC 853/2004

- laying down specific hygiene rules for food of animal origin

EC 854/2004

- laying down specific rules for the organisation of official controls on products of animal origin intended for human consumption

EC 1662/2006

- amending Regulation (EC) No 853/2004 of the European Parliament and the Council laying down specific hygiene rules for food of animal origin

EC 1664/2006

- amending Regulation (EC) No 2074/2005 as regards implementing measures for certain products of animal origin intended for human consumption and repealing certain implementing measures

EC 2073/2005

- on microbiological criteria for foodstuffs

EC 2074/2005

- laying down implementing measures for certain products under various EC Regulations [EC No. 852/2004; EC No. 853/2004; EC No. 854/2004; EC No. 882/2004

- 33 -

Appendix A:

Pasteuriser Performance Report Service Engineer Details:

Farm Details:

Name: Address:

Name: Address

Tel:

Tel:

Pasteuriser Details: Make:

Size:

Serial No.

Processing Check

Cleaning Check 4o C

A

Raw Milk in

Test Temp.

<

B

Cold Milk

Test Temp.

< 10oC

Holding tube temp. Thermograph temp. Hot temp. gauge

Thermograph temp.  0.5oC

Thermograph error Cold temp. gauge



Cold temp. gauge error

Wash return to tank

Yes

Achieves>60oC

No

0.5oC Mins taken to reach 60 oC

B-A

< 5o C

Difference between milk in and milk out

+ 30 mins = cleaning time of

Is flow diversion valve cleaned?

Milk Throughput (normal flow) Time taken to fill a

No

10 gallon Churn ( see table)

mins

60 x 10 mins taken

Yes

=

gals / hr

Are the pressures recommended by the

Yes

manufacturer maintained through Processing?

No

Milk Throughput (while homogenising) gals / hr

Milk Throughput (take-off to separator) gals / hr

Holding Tube

 72oC

Test temp.

Recommended Times

Thermograph temp.

Litres / hr 

Thermograph error

0.5oC

Hot temp. gauge  0.5oC seconds

Hot temp. gauge error Holding time

Flow Diversion



Test temp.

Flow divert

Yes

Pointer reset

No

Dye Test

110

700

3.87

155

900

3.00

200

1350

2.00

300

2000

1.35

444

Certification by Service Engineer  0.5oC

Pasteuriser Plate Integrity Tests (when required) Conductivity

Gals / hr

5.45

71.5oC

Setting

Pasteuriser thermometer error

Mins / 10 gals

500

I certify that I have carried out the checks on this pasteuriser and have found it to be pasteurising and cleaning satisfactorily

Other

Nature of Other Test

Signature

Condition of gaskets checked

Title Date

Visual inspection of pasteuriser

Note: If more than one Pasteuriser is installed a separate Report sheet must be produced for each Pasteuriser. - 34 -

View more...

Comments

Copyright � 2017 NANOPDF Inc.
SUPPORT NANOPDF