- Health Problems Associated -
- with Some Foods -

How to avoid food poisoning

Micro-organisms are present almost everywhere: in the air, soil, on our hands, in our bodies and in food. Not all of these tiny organisms are harmful and some are essential for good health and the production of food and drugs. Some can cause food spoilage and illness. Most forms of food processing either destroy these micro-organisms or reduce their numbers to safe levels.

Most micro-organisms can grow and multiply at temperatures between 15°C and 63°C, with most rapid growth occurring around 37°C. It is important that food is not held in this temperature range for long periods, as the food may become contaminated with large numbers of micro-organisms and cause illness. At higher temperatures most harmful microorganisms are destroyed, and at lower temperatures, such as in the refrigerator (1-4°C) or the deep freeze (-18°C), there is little or no growth. When cold foods are warmed, the micro-organisms will start to grow and multiply. Therefore it is important to heat food rapidly. The shorter the time spent in the temperature range where rapid growth of micro-organisms occurs, the lower the chance of food poisoning.

Some frozen foods such as vegetables, precooked foods and smaller cuts of meat can be cooked directly from the frozen state. Large cuts of meat should be thawed prior to cooking or extra cooking time should be allowed to ensure that the interior temperature reaches 71°C. Thawing is best carried out by placing the food in a refrigerator, allow at least 16 hours per kilogram. If not used after thawing it can be kept in the refrigerator chilling section for 1 to 2 days. Food that has been allowed to thaw in the kitchen should be cooked soon after thawing and not stored in a refrigerator. Packaged frozen foods have instructions on how best to prepare the food for eating. It is not advisable to re-freeze foods that have been thawed.

Because micro-organisms are very widespread, contamination of food can occur easily. Personal hygiene and a few precautions can prevent this leading to food poisoning and illness (see Figure 39 and the picture above).