Listeria

Listeria Guidance – Part 1 Sally Hasell

Purpose of Guide 1 1. Gives an overview of the issues – why controls are needed and why this need is becoming greater than ever 2. Identifies how Listeria gets into food via the environment, contaminated surfaces, ingredients and equipment 3. Explains why there must be a focus on RTE foods that support the growth of Listeria 4. Discusses microbiological limits and how they are applied 5. Describes how to setup, document and implement a Listeria Management Programme

What makes Listeria special? 1. Grows at low temperatures i.e. during refrigerated storage of food and in chillers 2. Grows in most types of packaging – vacuum packing does not inhibit it 3. Is everywhere in the environment, so can potentially be reintroduced into clean areas at any time 4. Is able to invade the cells of people with poor immune systems and cause very severe often fatal illness

Why Listeria needs to be controlled 1. Cases are few (20 a year) but high mortality rate (25%) and includes babies 2. If a large quantity of highly contaminated food got into the market, many could be hospitalised and die 3. Vulnerable consumers such as the elderly and those with poor immune systems are an increasing group 4. Food preferences are increasing the volume and types of RTE foods that Listeria can survive and grow in

Listeria sp. •Only Listeria monocytogenes is a significant human pathogen •Other members e.g. L.innocua are rarely harmful but share other characteristics with L.monocytogenes •This means finding any type of Listeria in food or somewhere it should not be, means that control is needed or has failed

Growth in food as a critical factor •Small numbers of Listeria are unlikely to be a problem for healthy adults but as numbers increase, the potential for illness increases •When number get really high, even healthy adults can become ill.

If Listeria can grow in a food, over time a small number can quickly become a large number, especially if temperature control not good HIGHEST RISK FOOD ARE THOSE THAT SUPPORT THE GROWTH OF LISTERIA AND ARE STORED CHILLED FOR MORE THAN 3 DAYS

Control strategies • Listeria present are destroyed or removed - apply a listericidal step, wash, incoming ingredient specs

•Limit the potential for growth in the food e.g. low pH ( 3 days

Products where the occurrence and/or survival is highly unlikely

Microbiological limits Regulatory limits that may apply to a product •Food Standards Code Std 1.6.1 •Product safety limits for dairy products (DPC1) •Operator defined limits •Customers •Countries to which exporting food

Listeria Management Programmes A record of how a business manages Listeria • What controls are in place e.g. specifications, cleaning/ sanitation, training, monitoring, responding to failures, new products and processes reviewed •How they are done e.g. new staff get trained, pasteurisation failures responded to, out of spec ingredients rejected, lab results acted on, new equipment checked

Listeria Management Programmes

Provides an overview of the Listeria control system so that everyone (management, auditor, regulator, customer) knows what is being done, their role and how to see and know when it is failing

Critical aspects of a LMP •It is written down •Everyone who needs to be involved is •It truly reflects what is happening in the processing environment •Observations made are responded to •It is a living document •It is focussed on the key factors that could be the source of contamination