Long, lazy, fun-filled days rounded off with a barbecue: meat cooked to perfection, or sometimes burnt to a crisp. But severe stomach pains three or six hours later, because of food poisoning, really takes the edge off your enjoyment.
Problems like this usually start with poor hygiene and inappropriate food preparation techniques. Careful attention; proper hygiene will prevent you from adding “barbecue belly” to the experiences of your friends.
While many people are fussy about the correct diet and take steps to avoid pesticide contamination of their food, the major risk to health from food is contamination by microbes.
Food poisoning caused by bacteria is rising throughout the world. What can you do to avoid such problems? The first step is for the cook to practice exemplary hygiene.
Shaking hands with everyone, blowing children’s noses and patting the dog will not give you the sterile hands needed to arrange and cook food and prepare salads. The basic precaution needed is to thoroughly wash your hands using soap, since some microbes can survive on the skin for hours.
Some soaps contain active ingredients that will kill these microbes; others rely on removing surface dirt and the outer layer of skin, so taking away any microbes. This doesn’t do us any harm since we are constantly shedding our entire outer layer of skin about once a week.
You need to keep the soap dry before use, because if the soap is wet and slimy it may even have its own colonies of microbes growing on its surface.
To avoid this use liquid soap from a dispenser.
One common bacterium, “golden staph” (Staphylococcus aureus) is sometimes present on food handlers and so may get into food. It can multiply at temperatures from 4°C to 46°C and produces illness because the bacteria contain a toxin.
Bacteria grow by enlarging and then splitting in half. They double their numbers about every half hour. So it is important not to leave salads and cold buffets such as chicken, ham, beef or seafood sitting in high temperatures since this will enable bacterial numbers to grow to high levels.
Cold foods should be kept cold since this slows down the bacterial multiplication rate. Cream or dishes containing cream, such as trifle, should be kept in the refrigerator until ready to be eaten. Some foods, such as pavlovas, will inhibit the multiplication of bacteria since they are high in sugar or salt.
Mayonnaise, curry and pepper may have high, bacterial counts and so should be put on food just, before it is eaten. This stops the bacteria from having time to multiply further. Some substances such as garlic cloves, rosemary and sage will slow bacterial multiplication.
Many people are aware of the threat of salmonella poisoning, which is gastroenteritis caused by salmonella bacteria. Frozen chicken is a common source of these bacteria.
Meat in general is a potential source of various kinds of bacteria. They may be present in the gut or other parts of the killed animal so each piece of meat needs to be cooked thoroughly to make sure all bacteria are killed.
Recently some states in the US have prohibited the serving of “rare” hamburgers because of the risk of some bacteria surviving such minimal cooking.
To make sure that meat is cooked properly, the meat or chicken needs to be thoroughly thawed. Otherwise bacteria deep inside the piece may still survive even if the outside has been burnt. The thawing is best done quickly using a microwave oven set on “defrost”.
If you thaw the meat by leaving it to stand at room temperature, the bacteria are given some chance to multiply to higher levels during this longer thawing time.
This increases the chance that some bacteria will survive the cooking. An alternative is to thaw the meat in a dish in a refrigerator.
You would need to take care that the thawing meat juices do not drip on to other food, so contaminating it. Meat should be marinated in a refrigerator to minimize the possible multiplication of the bacteria.
Because raw meat may contain bacteria it is sensible to use one cutting board for raw meat and another, or the other side of the board, for preparing directly edible foods such as salads. Otherwise these edible foods may be contaminated by bacteria from the meat.
Eggs are another potential source of contamination. Since the shell is added just before the egg is laid, bacteria from the chook may be trapped inside the shell or possibly on the surface.
Washing the eggshell often does more harm than good because it may damage the egg membrane (just inside the shell). If the membrane does become damaged, it will enable bacteria to enter the yolk or the white.
These are good media for supporting the growth of bacteria so that eating raw eggs or uncooked egg products is hazardous. Some egg farmers treat their chooks with antibiotics to reduce the risk of bacterial contamination.
About half the sickness traced to eggs has been found to be caused by salmonella. Eggs should be brought to room temperature before cooking, to prevent the bacteria from surviving the cooking. Heating the white and yolk to at least 80°C will kill most bacteria. This involves cooking them until they become solid.
If food is leftover and is to be eaten later, put it in shallow dishes so that it will cool quickly and keep it in a refrigerator. This will keep any bacterial multiplication to a minimum.
Multiplying bacteria are not the only barbecue hazard. European wasps may be attracted by sugar and enter drink cans. A wise precaution is to pour all drinks into a glass so that any wasps can be seen, or use a straw.
Many cooks, children and other bystanders have been burned when substances such as kerosene, methylated spirits or even petrol have been added to wood to encourage it to burn.
These substances are likely to flare suddenly over large distances or, in the case of petrol, explode with disastrous consequences.
Sensible care will enable everyone to enjoy happy memories of your barbecue.