What causes foodborne illness?
Some bacteria and viruses (microorganisms) can cause foodborne illness (also called food poisoning). You cannot tell by the look, smell or taste whether a food contains dangerous levels of microorganisms. These can either be present in food at its source, or can come from other people, surfaces or equipment, or other foods by cross contamination.
The ‘danger zone’ for food is when it is stored at temperatures at which bacteria can grow in most food. Food should always be stored at less than 5°C or at more than 60°C. This means perishable food must be kept refrigerator cold or steaming hot (so that steam is rising) to slow bacterial growth. Viruses do not grow in food but they can survive for long periods.
Prevention: what you can do...
- Store raw meat, fish and poultry near the bottom of the fridge and ensure that juices, which may contain microorganisms, do not drip onto other food. You can store these in leak-proof containers elsewhere in the fridge. Cover cooked and ready-to-eat food and always store these on shelves above raw foods.
- Cool hot food quickly. Cool food on the bench only until steam stops rising. Then place the hot food directly into the fridge or freezer.
- Check the temperature of your refrigerator using a fridge thermometer. Ideally, the temperature of the main compartment should be at 4°C to 5°C, and in the freezer should be around minus 15°C to minus 18°C.
Thawing of frozen products
- It is important to thaw cooked or ready-to-eat food in the fridge unless the manufacturer directs otherwise.
- Refrigerate defrosted food if it is not to be used immediately.
- If using a microwave oven, speed up the defrosting process by separating defrosted portions from the still-frozen sections of food.
Handling and preparation
- Wash hands in hot soapy water for around 30 seconds before preparing food and after touching raw meat, poultry, fish or pets. Dry hands thoroughly on a paper towel or a clean towel.
- Avoid preparing food if you have symptoms such as diarrhoea or vomiting.
- Do not use the same chopping board, utensils or serving platters for ‘ready-to-eat’ food, like salad vegetables, and ‘to be cooked’ food, like meat.
- When cooking mince, sausages, hamburger patties, and rolled or stuffed roasts ensure they are cooked right through. It is a good idea to check the internal temperature of these meats during cooking with a meat thermometer – aim for a temperature of 75°C. There should be no pink meat visible and juices should run clear.
Cooling and reheating
- Always reheat to steaming hot (above 75°C). This will kill bacterial cells and most viruses. When reheating in the microwave, make sure that food is steaming throughout by periodically stirring.
- Cool food as quickly as possible by placing into a shallow container and then into the fridge.
Special rules for barbecues
- Keep meat in the fridge until you are ready to barbecue it.
- Don’t use the same plate for raw and cooked food.
- Keep raw and cooked meat covered to protect it from flies and other insects.
- Keep perishable products in the fridge until needed. Guests may like to nibble on these throughout the function, but bacteria will also have a feast! It is best to serve small amounts and replenish with fresh portions as required. Don’t mix the fresh nibbles with ones that have been outside for some time.
- Don’t use excess barbecue marinade over cooked meat before serving, if you want to make a sauce separate out some before adding the meat or heat it thoroughly before serving.
- Put leftover cooked meats and other perishables into the fridge immediately.
- Microwaves don’t always cook food evenly, and microorganisms in cold spots may survive the cooking process. To avoid cold spots:
- Carefully follow any instructions on cooking in the microwave that come with the product.
- Cover the food with a lid or microwave-safe plastic-wrap, to trap steam.
- Stir food and turn large items over during cooking. Rotate the dish once or twice – even if you have a rotating turntable.
- Cut food into similarly sized pieces or arrange thicker pieces on the outside of the dish.
- Food continues to cook when the microwave is turned off. Always wait 3-5 minutes, or for the recommended standing time, before testing that cooking is complete.
- Wash all work surfaces, dirty dishes and utensils well with warm soapy water, and dry them thoroughly. If you use a tea towel for drying, change it if it becomes dirty or wet.
- Bacteria can grow in wet dishcloths, sponges and dish-mops, so rinse, wring and spread them out to dry after each use. They should be regularly changed, or disinfected by heating or soaking in bleach. The antibacterial dishcloths and sponges currently available in supermarkets should also be changed regularly.
- Disposable paper towels are an alternative to dishcloths and sponges.
- Never use the same dishcloths and sponges you use for food contact surfaces for cleaning floors or other areas around the house.
- Keep hot food steaming hot.
- Cool hot food quickly in the fridge.
- Cook food properly.
- Keep cold food refrigerated.
- Avoid cross contamination – keep raw food separate from cooked food, keep working surfaces and utensils clean, and frequently wash and dry your hands thoroughly.
One last reminder
Be extra careful preparing and cooking food for young children, the pregnant, elderly and sick people. They are particularly susceptible to foodborne illness.