Escherichia coli O157 (E. coli O157) is a particularly dangerous type of bacteria which can cause food poisoning. Only a small amount of bacteria can cause serious illness and in some cases it can be fatal, particularly in infants, young children and elderly people.
E. coli O157 has been found in:
- raw meat
- unpasteurised milk
- sprouted seeds
- salad vegetables
Normally cooking to above 75oc kills the bacteria, but often these foods are not cooked and contamination easily occurs after cooking. Cross-contamination can be controlled and prevented by basic hygiene rules;
- keeping raw and ready-to-eat foods separate, from delivery and storage, through preparation and cooking, to service
- proper cleaning and disinfection of all surfaces, equipment and utensils that could spread bacteria
- good personal hygiene at all times
All bacteria including E. coli are invisible food handlers must assume they could be present and handle foods accordingly. Most of this involves following simple, basic rules that have been taught on food hygiene courses for many years.
Three main ways to control the risk of cross-contamination
This is the most effective control measure:
- Raw foods must be kept strictly separate from ready-to-eat foods at all times - even if they are packaged.
- Where possible, provide separate work areas, storage areas, fridges and freezers, equipment, utensils, cloths, over-clothing and staff that handle raw and ready-to-eat foods. Good businesses even make sure deliveries come when there is no ready-to-eat food being handled.
- In exceptional circumstances, where you have very little space, You can also separate by time – preparing raw meat and vegetables before routine food handling and cooking takes place.
- Complex machinery for slicing, mincing or vacuum packing can be difficult to clean and disinfect thoroughly. Separate machines for raw and for ready-to-eat foods must be provided.
- If you have space or handle a lot of raw meat/soiled vegetables, you should designate a separate worktop and use it only for this.
- If you don’t handle a lot or have very little space, foods must never be chopped (prepared) directly on the surface, but separate boards or trays must be used.
- Where you can’t designate a separate area the surfaces must be cleaned and disinfected before being used for ready-to-eat food preparation. If the same refrigerator has to be used then raw food must be stored at the bottom.
- If a single freezer has to be used, raw food must be in a separate compartment away from ready-to-eat foods.
2. Effective Cleaning and Disinfection
This is always a two-stage process;
- Stage 1 - Cleaning should remove visible dirt, grease, food particles and debris, so that disinfectants can reach every part of a surface.
- Stage 2 - Disinfection destroys harmful bacteria. Disinfectant needs to be applied at the correct dilution for the correct amount of time to destroy bacteria. This contact time can vary between products, so you must read and follow the manufacturer’s instructions.
- Sanitisers have both cleaning and disinfection properties in a single product but the two-stage cleaning and disinfection process must still be carried out. In effect, the sanitiser should be used twice.
- Any disinfectant or sanitiser used must meet the official standards of BS EN1276:1997 or BS EN 13697:2001. You can normally check on the bottle that it meets this standard or contact the manufacturer.
If you have a dishwasher, you should use this to wash all equipment you use. To be effective, water reservoirs should be kept above 80oc for at least 15 seconds.
• If you don’t have a dishwasher, you should either:
• designate equipment (boards, knives, containers) for raw food handling and wash these separately after you have washed other equipment. The sink must be thoroughly cleaned afterwards, using a two-stage process. This equipment must be stored separately from ready-to-eat equipment
• alternatively all equipment after washing must be heat disinfected, using steam or boiling water. Caution will be necessary to prevent scalding injury, and devising a safe method is critical.
- It is best to use single use disposable cloths for wiping up raw meat or soiled vegetable spillages or cleaning these areas.
- If you use re-usable cloths, these should be discarded after wiping contaminated surfaces and washed on a washable cycle above 82˚c.
- A probe thermometer must not be used for testing raw food as well as ready-to-eat food. If you have not achieved a temperature of 75˚c or above. The thermometer it must also be rinsed with boiling water e.g. from a kettle, in addition to cleaning with probe wipes. Again caution will be necessary to prevent scalding injury, and devising a safe method is critical.
3. Handle Food Hygienically
It is particularly important to wash your hands after touching raw meat or surfaces. While you can fit non-hand operated taps to washbasins it may be easier and cheaper to ensure staff use a paper towel to turn off taps after hand washing. You will need to place paper towel dispensers by the wash basin, and ensure staff are trained and monitored. You also need to consider a good hand washing technique.
You will also minimise the handling of food by;
- buying already washed and prepared vegetables to avoid contamination by soil
- buying already prepared raw meat
- using tongs and other utensils to handle food, colour coded tongs etc. for raw and ready-to-eat foods will improve controls
- disposable gloves can be used to handle raw foods, provided they are disposed of once the task is completed. Hands should be washed before handling ready-to-eat foods. Again, separate packs or colour coding can help control cross-contamination.
If your aprons/overalls become contaminated while preparing/handling raw meat, you will need clean ones before handling ready-to-eat food. Providing disposable aprons for raw meat and vegetable preparation can help.
Updating your procedures
Many of these principles are part of generic food safety management systems like Safer Food Better Business (SFBB).
Visit the Food Standard's Agency website to download a copy of Safer Food, Better Business.