Food poisoning

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Food-borne infections and intoxications

The term food poisoning covers gastrointestinal disorders caused by the consumption of foods that are toxic in nature or that contain bacterial poisons or toxic impurities. Disorders caused by food poisoning are non-contagious, have a sudden onset, and are short-lived. They can cause immediate illness, even death. Bacterial food poisoning is called intoxication or alimentary toxinfection. Whilst traditional foodborne bacterial illnesses, such as typhoid and cholera, have faded, new and re-emerging ones have taken their place, such as [Cyclospora], resistant [Salmonella] and some strains of [E. coli]. Nonbacterial food poisoning is often caused by poisonous plants, poisonous fish or shellfish.

The organic and inorganic chemicals most commonly causing food poisoning are arsenic, copper, and sodium nitride. The most common organisms causing bacterial food poisoning are [Salmonella] spp (responsible for typhoid, paratyphoid, and other gastro-intestinal diseases); staphylococcal ([Staphylococcus] spp) food poisoning, tapeworm, trichosis and infectious hepatitis are also important causes of food-borne diseases. Conditions leading to food poisoning can be found throughout the world, but most frequently in developing countries. They include: lack of hot water; rodent and insect infestation; food handling by infected persons; improperly cleaned equipment; contamination of food by overhead sewage pipes; and incorrect temperature control in steam tables and refrigerators.


The risk of poisoning increases with the growth of the human and animal population. Mass production and distribution of food and the development of international trade contribute to the danger. There has been a marked increase in the varieties of dangerous bacteria in foods. Since 1975 some 25 new microbes than can cause food poisoning have been identified in the USA. Many are associated with intensive farming methods. It has been estimated that some 30% of animal feed is contaminated (with crowded factory farms allowing pathogens to spread easily) and some 60% of food retailed contains contaminants (with half the chickens sold containing [Salmonella]). Another source of contamination is new food preferences which necessitate the removal of preservatives from products in response to the consumer desire for natural foods.

Episodes of food poisoning and diseases such as salmonellosis are becoming increasingly common in the United States. An estimated 76 million cases of foodborne illness each year, resulting in more than 5,000 deaths and 325,000 hospitalizations annually given by one source in 2001. Another estimate (1998) suggested that as many as 33 million illnesses and 9,000 deaths annually are caused by foodborne hazards. Most of these cases can be traced to microbial contamination. Health effects from chronic pesticide exposures in the diet, particularly among children, are also causing increasing concern.

Although experts say everyone should take steps to prevent foodborne illness, young children, pregnant women, older adults, and people with weakened immune systems are at higher risk.

Food poisoning occurs more frequently in the summer months in many countries, such as Japan, where it peaks in August. In July and August of 1996 in Japan, 6000 school children were poisoned by the O-157 colon bacillus bacteria, [E. coli], in eel sushi and raw cow's liver. At least 2 people died.

In the spring of 1981, the consumption of adulterated edible oils poisoned thousands of people in the central area of Spain.

Up to four people a week may die from food poisoning in England and Wales and two thousand others suffer such bad vomiting, diarrhoea or other illness that they are officially recorded as food poisoning victims. Anything between 10 and 100 times that number may be infected and never report it to their GPs or the local authorities responsible for monitoring hygiene. Reported cases of food poisoning since the early 1980s have risen seven fold in England and Wales, four-fold in Scotland. The salmonella-in-eggs crisis of 1988 and the E. coli 0157 outbreak in Lanarkshire in 1996 demonstrated the dangers of careless food preparation. A five-year government-ordered study suggests 9.5 million people, a sixth of the population, are struck by some sort of intestinal disease annually at a cost of 3750 million to the National Health Service, employers and victims.

UK government figures from 1997 suggested that 44 per cent of all outbreaks of reported food poisoning - involving more than one household - might be put down to outside catering. Another 17 per cent was due to catering for large numbers in domestic kitchens. The rise in snacking and use of ready-prepared meals, steep falls in "home cooking" times from 2.5 hours in 1934 to 15 minutes now, and lack of kitchen know-how have all been blamed too. Between 5 and 10 per cent of reported food poisoning, more for some types of salmonella poisoning, may have resulted from holidays abroad. Poor storage and lack of temperature controls in shops and supermarkets, and poor hygiene in both public and private kitchens, are further causes of food poisoning.

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