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Street foods for sale in Africa
While food contamination from synthetic chemicals such as pesticides has been of growing concern to health authorities, naturally occurring microbiological food contaminants are a bigger threat to the world's general health. Diarrhoea from bacteria- and virus-contaminated food is estimated by WHO to run into billions of cases each year. Most of the victims are children under the age of 5 in developing countries.
Such illnesses continue to be a problem because food can be subject to harmful contamination from the soil it's grown in, from the animal it's derived from, from handling during processing and preparation, and from the dish it may be served on. A teaspoon of soil, for example, contains about 2000 million bacteria, while the human body carries some 150 types that number around 1 million. The vast majority of those bacteria are not harmful; some are even beneficial, and some are used in making food.
Generally, bacteria need food, moisture, warmth and time. Given the right conditions, some harmful bacteria found in foods can double their numbers in just 20 minutes. But it is also generally true that temperatures above 70°C (160°F) will kill most of them and cold temperatures will stop or slow their growth.
Bacteria-caused illnesses continue to be a problem despite great gains in technology. In fact, technology has led to the detection of some new or long unrecognized disease-causing organisms. Listeria, for example, is a growing problem. It is found in many if not most foods, and some strains are able to grow at refrigeration temperatures.
WHO officials have noted that some foods are frequently contaminated and that present-day technology cannot guarantee that raw meats are always free from Salmonella, Campviabacter or other harmful bacteria.
Other pathogens may also invade food or water supplies. Examples include the Vibrio micro-organisms that cause cholera and other diseases, and the aflatoxins, which are produced by a fungus that grows on groundnuts (peanuts), corn and other grains and are believed to cause cancer.
Many dangerous pathogens, particularly bacteria, are tasteless, colourless and odourless. So the best defense against them is good hygiene, and Codex Alimentarius has established recommended international codes of practice on food hygiene. General Principles of Food Hygiene is the basic document that covers production/harvesting areas (including transportation), facilities, personnel hygiene and hygienic processing requirements.
Other hygiene codes cover specific foods. They include:
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Fish |
Frog legs |
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Dried fruits |
Egg products |
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Fishery products |
Canned fruit and vegetable products |
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Desiccated coconut |
Low-acid foods |
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Crustaceans |
Dried milk |
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Tree nuts |
Dehydrated fruits and vegetables (including edible fungi) |
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Poultry |
Meat (fresh and processed) |
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Groundnuts (peanuts) |
Foods for infants and children |
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Game |
Mineral water |
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Quick frozen foods |
The trend in Codex's hygienic advisories is horizontal in the application of the
"hazard analysis critical control point" (HACCP) system. HACCP is a technique of identifying and monitoring those processing points where contamination can best be controlled.
Laboratory examination to ensure that foods are safe
