Listeriosis – guidance for food businesses
This guidance is specific to Listeria monocytogenes control and is designed to set out the steps you need to take, as a food business, to control the risk of listeriosis. The reason for this Guidance Note is that there has been increased cases of listeriosis in the UK.
What is it?
Listeriosis is a disease caused by the bacterium Listeria monocytogenes (L. monocytogenes). It is widespread in the environment and can be found in vegetation, raw foods, soil, water and animal faeces but is predominantly a foodborne disease. It can live in food processing environments and, because it is covered in a slime, it can attach to surfaces and can be difficult to remove and resistant to cleaning and disinfection. Food which comes into contact with it can become contaminated.
Unlike most other pathogenic bacteria, L. monocytogenes has the potential to grow at low temperatures, including refrigerator temperatures. It can grow in low oxygen environments, can survive freezing and is salt tolerant.
What harm can it do?
Effects can range from mild flu-like symptoms to bacteraemia, septicaemia, meningitis and, in pregnant women, miscarriage and stillbirth. Groups vulnerable to Listeriosis include people with weakened immune systems, pregnant women and the elderly. The effects include a high hospitalisation and fatality rate compared to infections with other bacterial pathogens.
Food types
Some types of food associated with listeriosis outbreaks include:
- Fish; smoked fish, cooked shellfish
- Meat; pate, cooked meats/poultry, cured meats
- Pasteurised/unpasteurised cheeses; soft blue veined cheeses, mould-ripened soft cheeses
- Prepared foods e.g. pre-packed sandwiches, salads, cut fruits, including melon.
Evidence suggests smoked fish is a high-risk product for invasive listeriosis in vulnerable groups in the UK, although the overall risk to the population remains low.
Ready-to-eat cold smoked fish is normally labelled as ‘smoked’ fish on its packaging. It has been cured (for example in salt) and then smoked at a low temperature, but it is not cooked through. Ready-to-eat cold smoked fish typically comes in thin slices, as shown in the image on this page. Examples include smoked trout slices and smoked salmon slices.
Guidance for vulnerable groups
The Food Standards Agency and UKHSA have published specific advice (higher risk of becoming ill with listeriosis Smoked fish and risk of listeriosis in high risk groups, including pregnancy and the immunocompromised - GOV.UK (www.gov.uk)) on eating ready-to-eat cold smoked fish for these vulnerable groups. Pregnant women or people with a weakened immune system are advised to avoid eating ready-to-eat cold-smoked or cured fish products, such as smoked salmon or gravlax.
As the risk of serious illness from listeriosis increases with age, older people should also be aware of the risk of eating cold-smoked and cured fish. The FSA recommends eating foods before the use by dates, ensuring the product is kept refrigerated (below 5°C) or considering using the safer alternatives below to minimise the risk of infection.
Safer alternatives
Safer alternatives for those at higher risk of listeria infection include:
- cooked smoked fish - this can be in dishes such as quiche, fish cakes, pie or gratin:
- cooking will kill any listeria that may be present
- if you are cooking smoked fish yourself, make sure it is steaming hot all the way through and served or chilled immediately. Cooked smoked fish may be served cold after being chilled in the fridge
- care should be taken with adding cold-smoked or cured fish to dishes like cooked pasta or scrambled eggs. Cook the fish first as warming it through as you prepare your meal will not heat the fish to a high enough temperature to kill listeria.
- tinned/canned smoked fish
- thoroughly cooked fish fillets (fresh or frozen)
Further dietary-specific advice and guidance
Precautionary dietary advice is available on NHS.UK for:
See also the Food Standards Agency website for further advice.
Personal hygiene
Implement a personal hygiene policy to ensure staff follow effective personal hygiene practices, such as:
- Handwashing controls.
- Staff to wear clean, and where appropriate, protective clothing.
- Food handlers preparing ready to eat (RTE) foods should not travel to their place of work in their protective clothing.
- Make sure work clothes are properly laundered for example on hot wash.
- Minimise handling of chilled RTE foods prior to service.
Cleaning and disinfection
- Make sure your work premises is well maintained, cleanable and clean (and disinfected where appropriate). This will minimise the risk and remove potential sources of L. monocytogenes contamination.
- Where possible disinfect food contact equipment by using the dishwasher on a hot setting cycle, following the manufacturer’s instructions.
- Use separate cleaning equipment for raw and RTE preparation areas to limit spread of contamination.
- Effective cleaning and disinfection is important for all food pathogens but points to be aware of in relation to L. monocytogenes are:
- Regular two-stage cleaning and disinfection
- stage 1: general cleaning using a detergent and
- stage 2: disinfectant.
- It is important to ensure food contact surfaces are cleaned appropriately and to avoid the formation and build-up of biofilms. If food comes into contact with a biofilm during food preparation, it can become contaminated.
- Keep moisture levels in food areas to a minimum. Repair damaged and poor floor drainage in kitchens, damaged flooring and areas where water can pool can be a reservoir for L. monocytogenes biofilms.
- Avoid accumulation of condensation in refrigerators and blast chillers, as this can create favourable conditions for biofilms, which may be distributed via dripping or moist air blown through the units.
Shelf life
- L. monocytogenes can grow in refrigerated storage. If you minimise the shelf life you will limit the opportunity for L. monocytogenes to grow to harmful levels.
- Follow manufacturer’s instructions for use-by dates and storage.
- Use foods within their use-by date and follow manufacturer’s instructions.
- Where products are made on site ensure the shelf life of the finished product, for example, sandwiches, does not exceed that of any of the ingredients. (Note: It is against the law to use or supply food past the manufacturer's use-by date).
- Set an appropriate shelf life, where foods are made on site, for example, a maximum chilled shelf life would be day of production plus 2 days should be applied, unless evidence of shelf life studies is provided to prove otherwise.
Cold chain
The management of appropriate chill temperatures is an essential food safety control for L. monocytogenes.
- Maintain the cold chain.
- Minimise the time that food spends out of the cold chain (during preparation, delivery, service etc).
- Some manufacturers may set a storage temperature lower than 5°C and these instructions must be followed.
- Deliveries of chilled RTE food should be placed in refrigerated storage promptly. Make sure you follow the ‘4 hour rule’ where rules provide an exemption for certain foods to remain out of temperature for one period of up to four hours for display and service purposes.
What do food businesses need to do?
- Food safety law requires all food business operators to have in place arrangements to control Listeria.
- Safer Food, Better Business (SFBB) are food safety management packs for small catering and retail businesses, residential care homes and childminders. Food businesses will be expected to control the risk of Listeria and other food safety risks in these types of businesses if the packs are fully implemented in food establishments that comply with the rules. Businesses do not have to use SFBB and can use other food safety management systems to control Listeria. SFBB packs can be ordered from our Safer food better business page.
- SFBB is not suitable for some types of business e.g. fish smokers and processors, manufacturers, butchers, fishmongers and bakers. These types of businesses should ensure they are run from food establishments that comply with the rules and have food safety management systems based on the Hazard Analysis and Critical Control Principles (HACCP) that:
- Look closely at what the business does, what could go wrong and what risks there are to food safety, including Listeria.
- Identify any critical control points the areas the business needs to focus on to ensure those risks are removed or reduced to safe levels.
- Decide what action to take if something goes wrong.
- Make sure procedures are being followed and are working.
- Keeping records to show procedures are working.
Further information:
For further information on HACCP, please visit the Food Standards Agency’s website.