FOOD 2010 Lecture Notes - Lecture 4: Bruce Ames, Nutrition Facts Label, Chronic Toxicity
14 Jul 2018
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Document Summary
On what basis is toxicity determined: animal feeding studies, or the exposure of animal or human cell cultures in vitro to additives, are typically performed. Mutagenic substances often turn out to be carcinogenic. The test uses a bacterial strain of salmonella typhimurium that has a defective (mutant) gene that prevents it from being able to make the amino acid histidine (his) from the ingredients in its culture medium. When placed into culture medium lacking histidine, mutant bacterial cells die: this type of mutation can be reversed, and the result is a fully functional organism, called a revertant, that is able to grow on medium lacking histidine. What enables the reversion is the presence of mutagen. The nutrition labelling and education act of 1990: nutrition labelling was established by the fda in 1973 to help consumers become more aware of the nutrient content of foods.
