Contamination is when harmful substances or microorganisms get into food. Cross-contamination is transfer from a raw food or a dirty object to ready-to-eat food. It is the most common mistake in kitchens.
How cross-contamination happens
- Chopping boards and knives. Raw chicken is cut on a board on which salad is then cut.
- Hands. A worker touches a raw ingredient and then food that will not be cooked any more.
- Cloths. One moment the table is wiped, the next the dishes.
- Dripping and spills in the fridge or on the counter.
- Poor storage of raw food next to ready-to-eat food.
- Unsuitable utensils and containers used for different foods without washing.
How to prevent it
- Use separate utensils for raw and ready-to-eat foods, for example colour-coded chopping boards.
- After working with raw meat, wash your hands and clean the surfaces.
- Keep raw and cooked foods apart in space and in time.
- Wash vegetables and fruit that will be eaten as they are.
- Cover ready-to-eat dishes.
- Food that was not used does not go back into its original container.
Under Regulation 852/2004 (Annex II, Chapter IX, point 3), food must be protected against any contamination at all stages of production, processing and distribution that is likely to render it unfit for consumption or harmful to health.
Cooking
The aim is for every part of the food to be heated through and for microorganisms to be destroyed. The biggest mistake is food that is burnt on the outside and cold inside. This applies to poultry, minced meat, offal, eggs and large pieces of meat.
- Check that the food is heated through completely, in the middle too. A thermometer is best.
- Follow the procedure and temperatures set by your HACCP. The general law does not prescribe a temperature for each dish.
- Minced meat and poultry are not cooked "pink".
- Raw eggs and dishes made with them are risky because of salmonella. For dishes that are not cooked, safer substitutes are used, for example pasteurised eggs.
Cooling
Food that is to be stored or served cold must be cooled as quickly as possible after heat treatment to a temperature that does not put health at risk (Regulation 852/2004, Annex II, Chapter IX, point 6).
- Divide large quantities into shallow containers.
- Do not leave a hot dish on the counter for hours.
- Once it has cooled, it goes into the fridge, not warm into an overfilled fridge.
Serving and hot holding
Under Decree No. 121/2023 Sb., hot dishes must reach the consumer within the time set by the operator and at a temperature of at least +60 °C. Dishes not served within that time cannot be kept any longer, reheated, chilled or frozen. Since they cannot even be kept, in practice whatever is left when the time is up is thrown away.
- Do not add fresh food to leftovers in a hot-holding container.
- Check the temperature of hot dishes with a thermometer.
- Serve with clean cutlery and utensils, not with your hands.
An example from practice
Soup was made in the morning and half a pot was left after lunch. Leaving it on the counter all afternoon and reheating it in the evening is exactly what must be avoided. Under Decree 121/2023, once the serving time is up a dish is no longer kept, reheated or chilled. The procedure for leftovers is set by your workplace's HACCP, and when it is not clear, ask your supervisor.
Leftovers
Leftovers do not go back into circulation. Throw away any food you are not sure about. The cost of the food is lower than the cost of one case of poisoning.