The difficulties of keeping the food supply chain in a worldwide network of food producers, processors and distributors are highlighted in an Editorial in this week's special gastroenterology edition of the Lancet.
Health officials in the USA are currently investigating how melamine, a chemical used to make industrial glues, fire retardants and fertilisers, got into the USA's food chain.
Investigators believe the chemical was added to rice-protein and wheat gluten supplements produced in China. Because purchasers of such imported products routinely measure nitrogen content to estimate the amount of protein in foods, it is believed the Chinese suppliers may have added melamine to make their products appear to contain more protein.
The adulteration was discovered after more than a dozen dogs and cats died after eating melamine contaminated pet food; scraps of this pet food were also fed to pigs and chickens destined for human consumption.
The Editorial says: "Although US health officials have determined that eating meat from these animals poses a very low risk to human health, the incident highlights how difficult it has become to guarantee food safety when the food supply depends on a vast worldwide network of producers, suppliers and distributors."