Maria, our food editor, looks at the different types of bacteria that can cause food contamination and their potential effects on your patrons' health.
I recently heard of a case in the US, where a restaurant patron sued the owners over a food hygiene breach that landed her in hospital. The customer ate undercooked chicken, which was contaminated with the dangerous bacteria Campylobacter. She was hospitalised for two weeks, and was unable to return to work for several weeks afterward, due to physical weakness caused by the illness. The woman received a record payout of over $20000 compensation for pain and suffering, and lost wages. The restaurant went out of business shortly after this incident, due to the bad publicity and the financial burden of the payout.
Now that lawsuits are becoming almost as common in Australia as in America, anyone involved in the food preparation business should be especially careful about the hygiene quality of food they are serving. Even if patrons who become ill after dining at your establishment do not take legal action, the drop in business simply caused by word of mouth can be significant.
Bearing this in mind, let's get to know some of the types of bacteria better, so that we can prevent them from rearing their ugly heads. Each type of bacteria needs to be tackled in a different way, so you should try to make yourself familiar with them all.
Staphylococcus
Without knowing it, many healthy people have staphylococci bacteria in their bodies. It's not actually the staphylococci themselves that make people sick, it's the way they multiply. If staphylococci get into wounds or food, they start to multiply, and this produces toxins. It is these toxins that make people sick.
Profile: Staphylococcus
Sources of contamination: nasal passages, mouth, infected skin wounds hands sneezing or coughing can be carried by dust, dirt, birds, animals or insects
Foods affected: cooked foods foods that are eaten cold or after mild re-heating, such as cream dishes custards and other milk products ready-made dishes hams and smallgoods
Prevention: maintain a high standard of personal hygiene use tongs or forks to serve cooked food handle or mix foods with disposable gloves where possible don't taste food with your fingers don't use the same utensil to taste food more than once keep foods below 4°C to prevent bacterial growth
Salmonella
Salmonella is one of the most common bacteria around. It's also one of the most harmful - it can be fatal to young babies or elderly people. Salmonella doesn't like temperatures below 4.5 °C or above 60 °C. This means that you can refrigerate food to prevent salmonella developing and that you can heat foods to boiling point to destroy it. However, it also means that salmonella thrives at room temperature, so never leave food sitting around for an extended period of time.
Profile: Salmonella
Sources of contamination: unwashed hands insects or rodents cross contamination of foods.
Cross contamination occurs when ready-to-eat foods are prepared with utensils or on surfaces that have been used to prepare raw foods.
Foods affected: raw meat poultry eggs or dried egg powder seafood from polluted water
Prevention:
wash your hands after going to the toilet wash your hands after you've handled raw foods and before you touch cooked foods cook all poultry to a minimum internal temperature of 70°C thaw frozen meat and poultry thoroughly in the refrigerator or cool room, not at room temperature don't use cracked eggs make sure that the kitchen is clean and free of rodents, insects and domestic pets
Clostridia perfringens
Clostridia perfringens is a very common bacterium. It is dangerous because it can form spores which withstand boiling, steaming, stewing or braising for up to five hours.
Profile: Clostridia perfringens
Sources of contamination: raw meat soil or dust unwashed hands
Cross contamination occurs when ready-to-eat foods are prepared with utensils or on surfaces that have been used to prepare raw foods.
Foods affected: large roasts, stews or curries
Prevention: adequately cook all foods before serving avoid partial cooking of foods on one day followed by reheating on the next day cool cooked foods rapidly and refrigerate promptly reheat foods quickly, thoroughly and serve immediately don't reheat foods more than once store unwashed, raw vegetables and cooked meats separately clean preparation areas, utensils and equipment in between preparing raw and cooked meats wash your hands after visiting the toilet
Bacillus cereus
Like clostridia perfringens, bacillus cereus also forms spores. It is usually found in the soil but can be found anywhere, including in dust and in the air. The spores can survive near boiling temperatures, particularly when they are near starches, such as rice or potatoes.
Profile: Bacillus cereus
Sources of contamination: cereals, especially rice vegetables, especially potatoes herbs and spices custard powder
Foods affected: boiled rice which has been allowed to dry/cool in the kitchen for several hours before use vanilla custards and similar desserts
Prevention: rapidly cool and store cooked or fried rice in the refrigerator or cool room don't store rice and meat dishes for prolonged periods of time don't add rice left over from the previous day to new batches of rice
Campylobacter
Food poisoning caused by campylobacter is similar to that caused by salmonella. However, the illness will seem like flu in the early stages and will be followed by abdominal cramps and diarrhoea in the later stages.
Profile: Campylobacter
Sources of contamination: animals and poultry poor personal hygiene cross contamination
Cross contamination occurs when ready-to-eat foods are prepared with utensils or on surfaces that have been used to prepare raw foods.
Prevention: store and handle foods correctly maintain a high standard of personal hygiene avoid cross contamination maintain clean premises and equipment
Listeria moncytogenes
Listeriosis is a dangerous disease that can, in some cases, be fatal. It is particularly dangerous for pregnant women, newborn babies, the elderly or people with weakened immune systems. Listeria moncytogenes bacteria are found in soil and water. Animals carry the bacteria and can therefore contaminate foods such as meats and dairy foods. Vegetables and some processed foods, such as cheeses and processed meats, may also be contaminated.
Profile: Listeria moncytogenes
Sources of contamination: soil dust water birds fish animals insects
Foods affected: milk products, particularly if they are made from unpasteurised milk raw meats processed meats cheeses, particularly soft cheeses like Brie and Camembert vegetables
Prevention: store and handle foods properly maintain a sanitised and hygienic environment avoid cross-contamination by washing utensils and preparation areas between handling raw and cooked foods
Botulism
Botulism is a serious form of food poisoning that is usually fatal, although fortunately it is very rare in Australia.
The bacteria which cause Botulism multiply in low acid foods in the absence of oxygen. Modern canning factories use extremely high temperatures to kill these dangerous bacteria. Botulism is usually the result of home canning or bottling processes, when the air is removed from the container, but not enough heat is applied to kill the spores.
Profile: Botulism
Sources of contamination: home canned or bottled low-acid foods
Cross contamination occurs when ready-to-eat foods are prepared with utensils or on surfaces that have been used to prepare raw foods.
Foods affected: vegetables (especially peas, peppers, corn, mushrooms or beans) meat or fish soups and sauces
Prevention: discard bulging or swollen cans discard glass bottles with bulging lids discard any canned foods that are foamy or have a bad odour be especially wary of home canned or bottled foods
nasal passages, mouth, infected skin wounds
