Wholesomeness of Irradiated Foods.

The history and applications of food irradiation are reviewed. The term wholesomeness when applied to food irradiation, embodies the concepts of microbiological and toxicological safety, and nutritional adequacy. The status of these areas of concern is reviewed. Nutritional studies have addressed the effects of irradiation on nutrient content and bioavailability, and evaluation of potential consequences of changes in either. Results of rat studies are presented in which we tested for the presence of anti-thiamin and anti-pyridoxine activity in radappertized chicken and beef. Test meats were analyzed for thiamin and pyridoxine to establish a basis for incorporation into repletion diets. Thiamin levels in gamma- and electron-irradiated, and thermally processed (commercial canning) chicken were 74, 34 and 78%, respectively, of the vitamin level in a frozen meat reference; the levels in beef were 77, 56 and 79%, respectively. Pyridoxine levels in chicken were 50, 38 and 17%, respectively, of the reference level. Rats were depleted in each vitamin, then repleted at two vitamin levels with diets containing test meats. Activities of transketolase, aspartate aminotransferase and alanine aminotransferase in erythrocytes from these rats provided no consistent evidence of antivitamin presence. It was concluded that these irradiated meats pose no problem regarding vitamins B1 and B6 if part of a complete diet.

Mutagenic potential of 4 organophosphinate compounds.

The mutation frequency of four organophosphinate compounds at various concentrations currently being investigated for their prophylactic ability in anticholinesterase poisoning was assessed using the sexlinked recessive lethal (SLRL) assay. Fisher's Exact Test indicated non-significant differences (P greater than 0.05) for: 4-nitrophenyl methyl (phenyl) phosphinate at 0.002 mM; 4-nitrophenyl monochloromethyl (phenyl) phosphinate at 0.007, 0.05 and 0.01 mM; 4-nitrophenyl diphenyl phosphinate at 0.35 and 0.51 mM; and 4-nitrophenyl dimethyl phosphinate at 0.005 and 0.01 mM compared to concurrent negative controls. This non-mutagenic activity of these four compounds was also confirmed by other researchers using the Ames assay.

A continuous-flow (AutoAnalyzer II) procedure for measuring erythrocyte transketolase activity.

In this semiautomated method, an AutoAnalyzer II is used to measure the enzymic production of glyceraldehyde 3-phosphate in hemolysates, to assay erythrocyte transketolase (EC 2.2.1.1) activity. Hemolysate and indicator reactions are separated by dialysis to eliminate hemoglobin interference and increase sensitivity. Internal standards of glyceraldehyde 3-phosphate in hemolysate carriers were quantitatively measured with good precision and accuracy in the presence or absence of the transketolase substrate, ribose 5-phosphate. Chart-recorder values for these standards were used to calibrate the AutoAnalyzer output in IUB units (U) of transketolase activity. Substrate-product relationships were examined to characterize reaction kinetics and optimize assay conditions. AutoAnalyzer transketolase results correlated well with those from two manual procedures.