Whether you have a career in food preparation, entertain privately, or just cook for your family, food handling has some science to it that you should know. What with hearing a story in the news every other day about yet another Salmonella or E. Coli outbreak, we could all stand to hear a refresher course in the sanitary preparing of food.

Handling food

Wash and dry hands thoroughly before handling food. Always use clean kitchen utensils for handling foods. Keep raw and cooked food apart at all times. Apply this especially to raw meat, fish, and poultry. Keep these away from cooked foods and ready-to-eat foods. Wash and dry hands, utensils, cutting boards, knives, and flat surfaces thoroughly after preparing raw meat, fish, poultry and other raw foods and before contact with other food. Ideally you should use separate cutting boards for raw and cooked foods. Never put cooked food onto a plate which has previously held these raw foods until it has been washed. Do not use the same utensil to stir or serve a cooked meal that was used to prepare the raw ingredients.

Vegetables of the root family such as potatoes, leeks and carrots often have traces of soil on them which can contain harmful bacteria, so wash them thoroughly before use. As a rule you should wash other fruit and vegetables too, especially if they are going to be eaten raw. Avoid preparing food for yourself or others if you are sick.

Defrosting

When cooking packaged frozen foods always follow instructions provided for defrosting or cooking directly from frozen. If cooking from frozen allow sufficient time for food to be thoroughly cooked and check it before serving; an extra minute in the fryer won't hurt it. When defrosting foods make sure they are fully defrosted before cooking; being sure to allow food enough time to thaw. Never re-freeze food once it has started to thaw.

Thaw food by placing it on the bottom shelf of the fridge in a container to catch any juices, or in a bin or rack over a sink. These juices will often be contaminated so wash dishes and hands thoroughly after use. Only thaw food in a microwave oven if it is to be cooked immediately. To thaw very large meat items like turkeys, leg of lamb, etc. more quickly, let them defrost outside of the fridge. Put them in a cool place and make sure they are completely thawed before cooking.

Cooking and heating

Follow recipes and label instructions on cooking times and temperatures.

Remember to preheat the oven properly - the instructions for preheating take into account that the cooking time should be at the full temperature. Cook all foods until they are piping hot. Remember that sausages, burgers, pork and poultry are cooked all the way through and they should not be rare or pink in the middle. As a test, pierce it with a knife; any juices that run out of the meat should be clear, not bloody. Lamb and beef (except when minced or rolled) can be eaten rare, but you should make sure the outer surface is thoroughly cooked to kill any germs on the surface of the meat.

Elderly or sick people, babies, young children and pregnant women should only eat eggs cooked until both yolk and white are solid and should never eat raw or partially cooked seafood. Don't cook foods too far in advance. Once cooked, foods should be kept covered and piping hot (above 145F) until it's time to serve them. Keep prepared cold foods in the fridge until you are ready to serve them.

When using a microwave, stir foods and drinks and allow them to stand for a couple of minutes to avoid hot or cold spots. Check that food is hot throughout before serving. Foods that are not thoroughly cooked should be re-heated for another few minutes, but when it comes to microwaves food should not be reheated more than twice.

Cooling

Never put hot food directly into the fridge or freezer, let it cool sufficiently first. Cooling should be completed within one or two hours after cooking. To speed cooling you can divide foods into smaller portions, place in a wide dish and stand this in a shallow tray of cold water.

Extra care for babies

Because babies' immune systems are less developed than those of an adult, they are at a greater risk of illness. To take extra care for young babies, wash bottles and utensils in hot soapy water and sterilize them using a sterilizing solution or a steam sterilizer. When adding water to baby foods, milks and other drinks always use bottled water and never water straight from the sink tap. Cook foods thoroughly until piping hot and cool them rapidly until they are comfortable to eat.

Extra care with barbecues and grills

Cooking food outdoors, particularly for large groups, can increase the risk of food poisoning. It's harder to keep foods very hot or very cold and to keep everything clean. But with a little extra care barbecues and outdoor grills can be used safely.

Light the barbecue well in advance, making sure that you use enough charcoal and wait until it is glowing red with a powdery gray surface before starting to cook. Keep meats, salads and other perishable food in the fridge, or in an ice-packed portable cooler box, until just before you are ready to cook them. Serve salads at the last minute. Ideally use separate cooler boxes for raw meats and ready-to-eat foods. Cooler boxes can only keep food cool for a limited period so cook sooner rather than later. Better still,

if possible, fully pre-cook all poultry and sausages in an indoor kitchen and then take them straight to the barbecue to add the final barbecue flavor.

During cooking, turn food often. If it starts to burn on the outside raise the grill height or reduce the heat of the charcoal. You reduce charcoal's heat by dampening the coals slightly or partially closing the air vents. As always, cook poultry, burgers, pork and sausages throughout with no pink bits in the middle. Keep raw and cooked foods apart at all times.

Don't handle cooked foods with utensils that have touched raw meats and don't put cooked or ready-to-eat foods such as salad and bread on plates that have held raw meats.