Techniques such as radioimmunoassay (RIA), agglutination, and enzyme-linked immunosorbent assay (ELISA), require less concentration of the food extracts ; thus, they save time and are more sensitive. Latex agglutination (16) appears promising as a serological tool for identifying staphylococcal enterotoxins. Several ELISA methods (26,28,30,32,37,38,39) have been proposed for the identification of enterotoxins in foods, but, except for a polyvalent ELISA (7,9), their specificity has not been studied extensively.
Among ELISA methods, the "double antibody sandwich" ELISA is the method of choice, because reagents are commercially available in polyvalent and monovalent formats for both toxin screening and serotype specific identification(22). An automated enzyme-linked fluorescent immunoassay (ELFA) has been developed and is commercially available.
This method has undergone specificity and sensitivity evaluations and has proven to be an effective serological system for the identification of staphylococcal enterotoxin in a wide variety of foods (14). Other methods, which have been used in the identification of the staphylococcal enterotoxins and may have application in foods, are the T-cell proliferation assay (35), and polyacrylamide gel electrophoresis (PAGE) combined with Western blotting (2).
References
http://www.cfsan.fda.gov/~ebam/bam-13a.html
Wednesday, July 18, 2007
toxic substances
Toxic Substances
Toxicant is a substance which when ingested at high levels produces harmful actions on Biolog mechanisms.
Natural toxicants can occur as contaminants of natural food products or as normal components of such foods. Contaminants can be of microbiological origin, such as toxins produced by bacteria, or they can be taken up by the food product in its normal growth process.
Comparative toxicology refers to comparing the concentration of inherent toxins, those that are naturally occurring and present in the food with the concentration of inherent toxins in the traditional counterpart of the new food.
Inherent substances are a subset of the naturally occurring chemicals that includes all substances except those that are not of biosynthetic origin and that are intentionally introduced into food through human activity. It is through this definition, mycotoxins are naturally occurring, even if they developed through mould growth.
Inherent toxicants are not the only undesirable food constituents. Food contaminants may be naturally occurring or synthetic.
The most important are naturally occurring contaminants in particular those produced by microorganisms. Microorganisms or their toxins occur far more frequently. Two general kinds of microbial toxins are mycotoxins and bacterial food poisoning toxins.
References
http://www.nafex.org/jansonfiles/JansonJuly77.htm
http://extoxnet.orst.edu/faqs/natural/page1.htm http://www.foodstandards.gov.au/_srcfiles/fsc_1_4_1_Contaminants_v78.pdf
Toxicant is a substance which when ingested at high levels produces harmful actions on Biolog mechanisms.
Natural toxicants can occur as contaminants of natural food products or as normal components of such foods. Contaminants can be of microbiological origin, such as toxins produced by bacteria, or they can be taken up by the food product in its normal growth process.
Comparative toxicology refers to comparing the concentration of inherent toxins, those that are naturally occurring and present in the food with the concentration of inherent toxins in the traditional counterpart of the new food.
Inherent substances are a subset of the naturally occurring chemicals that includes all substances except those that are not of biosynthetic origin and that are intentionally introduced into food through human activity. It is through this definition, mycotoxins are naturally occurring, even if they developed through mould growth.
Inherent toxicants are not the only undesirable food constituents. Food contaminants may be naturally occurring or synthetic.
The most important are naturally occurring contaminants in particular those produced by microorganisms. Microorganisms or their toxins occur far more frequently. Two general kinds of microbial toxins are mycotoxins and bacterial food poisoning toxins.
References
http://www.nafex.org/jansonfiles/JansonJuly77.htm
http://extoxnet.orst.edu/faqs/natural/page1.htm http://www.foodstandards.gov.au/_srcfiles/fsc_1_4_1_Contaminants_v78.pdf
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