Our habitat is teeming with countless microorganisms that are invisible to the naked eye (bacteria, viruses, fungi, parasites). Many of these tiny creatures are harmless to humans, some are even useful, and against others the human body has built up defense mechanisms. However, under certain circumstances (at specific temperatures and in the presence of essential nutrients) these organisms can proliferate very quickly and on a very large scale, thus endangering health. Dirt and waste, and also food itself, offer an ideal breeding ground for these creatures.
Food poisoning is common
Food contamination with microorganisms or poisoning with their metabolites can produce illnesses called “food poisoning”. Such disorders may be caused by bacteria, like salmonella, campylobacter or listeria, or by mould toxins etc. According to official statistics, salmonella and campylobacter account for the most frequently recorded incidents. Official data are based on reports from doctors and hospitals and generally only involve relatively serious cases of illness. In the last ten years, an annual average of more than 5,000 cases of salmonella poisoning were reported in Switzerland. Incidents are especially common in the hot summer months – in the last few years, for example, 600-800 campylobacter infections were reported in this country during the month of August.
If the symptoms are relatively mild (diarrhoea, abdominal pain, vomiting, headache, fever, malaise), a doctor is usually not called, the possibility of food poisoning is generally not considered, and the cause is often put down to overeating or excessive drinking. The doctor’s opinion is therefore not sought, and thus notification and statistical records are lacking. For these reasons, experts assume that a considerable number of cases go unrecorded and that only about one out of ten cases is reported.
Producers and distributors in recent years have achieved a very high standard of safety in the processing of foods. But food-poisoning incidents still occur, particularly with raw, i.e. unprocessed food of animal or vegetable origin. Hygiene problems can occur anywhere in the food cycle, i.e. from production, through the storage or selling of food, right up to the preparation of a meal. Food preparation, both in industry and in the private kitchen, is the most frequent site of contamination.
Incidents almost always result from a poor knowledge of the most important rules of hygiene or from human error – in the majority of cases, therefore, they can be avoided. Greater caution in the handling of food can prevent the following:
- A deterioration of quality as a result of contamination or loss of nutrients, and thus a decrease in value of the food
- Food perishing and having to be destroyed or thrown away
- Diseases that can have serious – or even fatal – consequences, particularly in small children, pregnant women, and the elderly.
Microorganisms are passed from “hand to hand” – after dirty work, contact with raw food (in particular meat), handling of waste, dirty implements and articles, and especially after using the toilet, germs often remain on the hands, under watches, jewelry, or fingernails.
Wash hands thoroughly with soap, and keep fingernails clean.
Microorganisms settle in clothes and tissues and by this route find their way onto food.
Wear clean clothes (both at work and in the kitchen).
Skin rashes, wounds (even very minor cuts) and inflammation secrete germs (pus).
Keep wounds and rashes covered with a watertight dressing, and work with rubber gloves.
Saliva and mucus contain a lot of microorganisms.
Do not cough or sneeze on food and meals – turn away and hold a hand or handkerchief in front of the mouth.
People with infectious diseases (fever, cough, flu, diarrhea, jaundice etc.) always secrete germs.
People with infectious diseases should not work in the kitchen, or if they do should wear protection over the mouth.
Prepacked food, canned goods and deep-frozen products must carry a date of expiry. A limit can also be given for how long food may be consumed after the pack has been opened.
When making your purchase, note the “sell-by” and the “best before” dates, periodically check the food in your cupboards, refrigerator and freezer.
Raw food is often contaminated with germs or parasites, depending on the type of food and its origin. Certain groups of food are particularly susceptible (milk, tartare, minced meat, eggs, poultry, fish and seafood etc.). Room temperature encourages the growth of existing germs, and hot weather increases the risk.
Transport raw food quickly and under cool conditions and keep it in the refrigerator until use (do not break the “refrigeration chain”). Consume susceptible food immediately.
It is a good idea to keep food in the refrigerator or in the freezer – but only if the recommended temperatures are observed. In refrigerators or freezers that are overstocked (e.g. in preparation for parties) or severely iced up, the temperature may rise.
Periodically check the refrigerator (max. 5 degree C) and freezer temperatures (at least -18 degree C) with a thermometer. Defrost them if they are iced up.
Deep-frozen products offer the advantage of being able to keep food for a relatively long period. Problems of hygiene can occur, however, when they are thawed out (either intentionally or unintentionally).
Once food has thawed out, do not refreeze it (even after it has been cooked). To thaw out deep-frozen products, place them in a vessel in the refrigerator or in the microwave oven to prevent the escape of liquid from the thawing process onto other food, shelves, work surfaces or equipment.
If food is not properly stored or is stored for too long (even in the refrigerator), it may perish. This not only affects the smell, taste and nutrient content of the food – if it shows signs of decay, cloudiness, colour change, viscidity, fermentation, formation of mould (except for the blue mould that occurs on cheese and salami) etc. this always indicates the presence of dangerous germs and toxic substances.
Immediately throw away any food that has perished. Do not simply cut off the mould – the toxic spores of the mould spread through the food invisibly.
Germs from raw food can be transferred to cooked meals during storage and processing.
Keep cooked meals covered during storage; store and prepare raw and cooked food separately. Clean any work surfaces and utensils used in the processing of susceptible food immediately after use. Wash your hands each time.
Inadequate heating in the preparation of food prevents the germs from being killed.
When cooking raw food, ensure that the inner temperature reaches at least 70 degree C. Completely thaw out deep-frozen products, so that they are sufficiently cooked on the inside as well. Also, when using leftovers, make sure you heat them to 70 degree C. Use special thermometers if necessary.
When food has been prepared, cold dishes, warm meals and leftovers form an ideal breeding ground for the proliferation of microorganisms.
Consume any meals prepared as soon as possible. Keep cold dishes in the refrigerator at max. 5 degree C until consumption, and heat cooked meals to at least 60 degree C. Immediately put any leftovers in the refrigerator at max. 5 degree C in flat containers and consume as soon as possible.
Equipment and kitchen hygiene
With their combination of dirt and humidity, dishcloths, sponges, tea towels, brushes etc. provide ideal conditions for microorganisms to proliferate.
Keep kitchen aids dry; change cloths and cleaning utensils frequently or wash them in boiling water – where possible use disposable household tissue.
Dried food residues, sauce sprinklers, peelings etc. always contain a lot of microorganisms.
Clean work surfaces, kitchen equipment and utensils thoroughly every time after use, preferably with soap and hot water.
Food residues, peelings, dust or dirt are often found under work surfaces, furniture, and equipment – and provide a breeding ground not only for microorganisms, but also for insects and other parasites.
Keep the kitchen and cellar storage rooms clean. Separate waste (glass, metal, waste for composting, etc.) and dispose of it as soon as possible. In cases of severe or frequent infestation, consult a specialist.
Many households keep pets. These can secrete germs or carry germs in their fur or feathers etc.
No matter how domesticated, pets do not belong in the kitchen and storage rooms.
- Cleanliness is the first priority: pay attention to personal hygiene, hygiene in handling food, and cleanliness at the workplace.
- Easily perishable food belongs in the refrigerator (max. 5 degree C) or in the freezer (at least -18 degree C).
- Make sure you heat food adequately (at least 70 degree C) during cooking.