Preventing E. coli O157 Cross-Contamination in Food Businesses

E. coli O157 bacteria are invisible to the naked eye. Food, equipment and surfaces can therefore become contaminated without anybody realising.

Only a small number of harmful bacteria may be needed to cause serious illness. In some cases, an E. coli O157 infection can be life-threatening.

What Is E. coli O157?

E. coli O157 is a harmful type of bacterium that can cause severe food poisoning. Possible symptoms include:

• Severe stomach cramps
• Diarrhoea
• Bloody diarrhoea
• Nausea
• Vomiting
• Fever in some cases

Some people may develop a serious complication called haemolytic uraemic syndrome, or HUS. This condition can damage the kidneys and may be life-threatening.

Who Is Most at Risk?

Anyone can become ill following an E. coli O157 infection, but the risk of serious complications can be greater for:

• Babies and young children
• Older people
• People with weakened immune systems
• People with certain existing health conditions

How Does E. coli O157 Spread?

E. coli O157 can spread through:

• Contaminated food
• Contaminated water
• Contaminated hands, equipment and surfaces
• Contact with infected animals or their environment
• Person-to-person transmission

Food businesses must maintain high standards of hygiene at all times to prevent harmful bacteria from spreading.

Food Standards Agency Guidance on E. coli O157

The Food Standards Agency has produced guidance to help food businesses prevent E. coli O157 cross-contamination. Although the guidance focuses on E. coli, the same controls can help prevent the spread of other harmful bacteria, including:

• Salmonella
• Campylobacter
• Listeria

Separate Raw and Ready-to-Eat Food

One of the most important food safety controls is the strict separation of raw food from ready-to-eat food.

Ready-to-eat foods are foods that will not be cooked or reheated before being served. Examples include:

• Salads
• Cooked meats
• Sandwiches
• Cheese
• Prepared fruit
• Desserts

Because there is no further cooking stage to destroy harmful bacteria, preventing contamination is essential.

Use Separate Food Preparation Areas

Food businesses should separate raw and ready-to-eat food using different:

• Rooms or designated preparation areas
• Members of staff, where appropriate
• Work surfaces
• Utensils
• Equipment

Where possible, businesses should create a designated clean area that is used only for preparing ready-to-eat food.

Temporary Separation Controls

Where permanent separation is not possible, areas may be shared only when effective controls are in place. Sharing an area presents a greater risk and requires:

• Thorough cleaning and disinfection between tasks
• Clear separation of raw and ready-to-eat activities
• Carefully planned workflows
• Effective staff supervision
• Documented food safety procedures

Use Separate Equipment and Utensils

Separate chopping boards, knives, utensils and other equipment should be used for raw and ready-to-eat food. Many businesses use colour-coded equipment to make items easy to identify and reduce the risk of mistakes.

Food-contact surfaces and equipment used for ready-to-eat food must be:

• Kept in good condition
• Easy to clean and disinfect
• Protected from contamination
• Stored separately from equipment used with raw food

Complex Food Equipment

Complex equipment such as vacuum-packing machines, slicers and mincers should not normally be used for both raw and ready-to-eat food during the same working day.

If the use of a machine is changed from raw to ready-to-eat food, it must be fully dismantled, cleaned and effectively disinfected before it is used again.

Cleaning Shared Equipment

Where suitable equipment must be shared, it must be properly cleaned and disinfected between uses. A commercial dishwasher operating with an appropriate cycle may be used for suitable dishwasher-safe items.

Cleaning removes dirt, grease and food debris, while disinfection reduces harmful microorganisms to a safe level. Both stages must be completed correctly.

Store Raw and Ready-to-Eat Food Safely

Raw food must be stored separately from ready-to-eat food. Raw meat and poultry should normally be stored in suitable covered containers below ready-to-eat food.

This helps prevent blood, liquid or other material from dripping or leaking onto food that will not be cooked again.

Safe Food Storage Practices

• Keep raw food covered and contained
• Store raw meat and poultry on the lowest suitable refrigerator shelves
• Keep ready-to-eat food above and away from raw food
• Use clearly identified storage containers
• Keep raw and ready-to-eat equipment separate
• Clean spills immediately using the correct procedure

Maintain Effective Hand Hygiene

Thorough handwashing is essential for preventing E. coli O157 cross-contamination. Food handlers must wash their hands using an effective technique, particularly:

• Before preparing food
• After handling raw meat, poultry or other raw ingredients
• After touching waste or bins
• After cleaning
• After using the toilet
• After touching the face, hair, phone or personal belongings
• Before handling ready-to-eat food

Hands should be washed with warm running water and liquid soap, then dried thoroughly using a hygienic method.

Hand Gels and Disposable Gloves

Antibacterial hand gel must not replace proper handwashing. It may be used after handwashing as an additional control where appropriate.

Disposable gloves are also not a substitute for handwashing. Gloves must be changed as frequently as hands would need to be washed, and hands must be washed when gloves are changed or removed.

Control Food Temperatures

Temperature control helps prevent harmful bacteria from multiplying. Many bacteria grow rapidly in warm and moist conditions, particularly within the temperature danger zone between approximately 5°C and 63°C.

To control bacterial growth:

• Keep chilled food at 5°C or below wherever possible
• Keep food requiring hot holding at 63°C or above
• Check and record temperatures in accordance with workplace procedures
• Minimise the time food spends at unsafe temperatures
• Cook and reheat food thoroughly

Food that requires refrigeration must normally be kept at 8°C or below in England, Wales and Northern Ireland. Setting refrigerators at 5°C or below provides a useful safety margin.

Use Disinfectants and Sanitisers Correctly

Cleaning products, disinfectants and sanitisers must be suitable for their intended use and meet recognised standards where required.

Always follow the manufacturer’s instructions, including:

• The correct dilution rate
• The required contact time
• Whether the surface must be rinsed
• Whether visible dirt must be removed first
• The correct storage and handling precautions

A disinfectant will not work effectively if it is used at the wrong concentration or removed before the required contact time has passed.

What to Do If E. coli Contamination Is Suspected

If contamination is suspected, food preparation should stop in the affected area until the risk has been controlled.

The business should:

• Identify and isolate potentially contaminated food
• Prevent the food from being supplied or served
• Clean and disinfect affected surfaces and equipment
• Dispose of contaminated food safely
• Investigate how the contamination occurred
• Review food safety procedures
• Record and report the incident where required

Food that may have been contaminated must never be supplied to customers.

If Contaminated Food Has Reached Customers

If potentially contaminated food may already have been supplied, the business must act immediately. This may include:

• Contacting the local authority or relevant enforcement officer
• Following food withdrawal or recall procedures
• Identifying affected batches or products
• Contacting customers or other businesses where necessary
• Keeping accurate records of the action taken

Reducing the Risk of E. coli O157

Controlling E. coli O157 requires effective separation, thorough cleaning and disinfection, safe food storage, temperature control and proper handwashing.

By following these essential food hygiene procedures, food businesses can significantly reduce the risk of cross-contamination, protect their customers and help prevent serious illness.