Box 2-12. Common microbiological contaminants in food.

In Latin America, the most frequent bacterial agents involved were Salmonella spp. (20% of the reported outbreaks) (FAO/ WHO, 2004), Staphylococcus aureus, and Clostridium perfringens (CSPI, 2005). Another pathogen, Escherichia coli O157:H7, has increased dramatically in Central and South America. Argentina has one of the highest incidences of HUS-a serious complication of E. coli infection-especially in the pediatric age group (CSPI, 2005).

     Food items most commonly associated with the reported outbreaks were fish/seafood (22%), water (20%) and red meats (14%) (CSPI, 2005). Examples include a major E. coli O157:H7 outbreak in Japan linked to sprouts involving more than 9,000 cases in 1996, and several recent Cyclospora outbreaks associated with raspberries in North America and Canada, and lettuce in Germany (Bern et al., 1999; Hodeshi et al., 1999; Döller et al., 2002). In 1994, an outbreak of salmonellosis due to contaminated ice cream occurred in the USA affecting an estimated 224,000 persons. In 1988, an outbreak of hepatitis A, resulting from the consumption of contaminated clams, affected some 300,000 individuals in China (Halliday et al., 1991). In 2005 in Finland, the most common cause of food and water-borne food poisonings was noro-virus (EVIRA, 2006). A 1998 outbreak of Nipah virus typically associated with pigs and pork (WHO, 2004) killed 105 people in Malaysia. The parasitic disease trichinellosis is increasingly reported in the Balkan region among the non-Muslim population, owing in part to the consumption of pork products processed at home without adherence to mandatory veterinary controls.

Box 2-13. Chemical contamination of food: A few examples.

• Mercury: As many as 630,000 children are born each year exposed to mercury in the womb (Ahmed, 1991).
• Non-persistent organic compounds: In Spain in 1981- 1982, contaminated rapeseed oil denatured with aniline killed more than 2,000 people and caused disabling injuries to another 20,000-many permanently (CDCP, 1982).
• Pesticide residues: The latest European monitoring of pesticide residues in food found 4.7% of all samples exceeding the legal threshold of pesticide residues in food and almost half of all samples had detectable levels of pesticide residues (EC, 2006); Viet Nam reports a high burden of disease associated with pesticide residues (Nguyên and Dao, 2001).
• Accidental pesticide poisonings: In India, in July 1997, 60 men were poisoned by eating pesticide-contaminated food at a communal lunch (Chaudry et al., 1998); in Tauccamarca, Peru, 24 children died in October 1999, after consuming a powdered milk substitute contaminated by the organophosphate pesticide methyl parathion, and 18 others suffered neurological damage (Rosenthal, 2003); in the Philippines, carbamate poisoning killed 28 schoolchildren and caused vomiting and diarrhea spells in 77 others in March, 2005 (Neri, 2005).
• Deliberate poisoning: In China, in 2002, more than 200 school children sickened and 38 died when rat poison was used to intentionally contaminate bakery products. (CNN, 2002).
• Naturally-occurring toxins: The chronic incidence of aflatoxin in diets is evident from the presence of aflatoxin M1 in human breast milk in Ghana, Nigeria, Sierra Leone, and Sudan and in umbilical cord blood samples in Ghana, Kenya, Nigeria, and Sierra Leone. Together with the hepatitis B virus, aflatoxins contribute to the high incidence of primary liver cancer in tropical Africa. Moreover, children exposed to aflatoxins may experience stunted growth or be chronically underweight and thus be more susceptible to infectious diseases in childhood and later life. (CSPI, 2005).
• Growth hormone: The EU banned the use of growth hormones in livestock in 1988 but the practice still continues in the US, Canada and in Australia.
• Dioxin: Exposure to dioxin causes serious adverse health effects, and remains a major public health concern in Europe, the United States and elsewhere (Schecter et al., 2001; NAS, 2003).