Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid with conjugated double bonds. Several investigators have suggested that CLA has anticarcinogenic properties. This study describes the quantification of CLA isomers in three Cheddar-type cheeses relative to the effects of different cheese cultures, processing conditions, and aging periods. An improved method was developed for quantifying CLA isomers in cheese such that isomerization did not occur. Three 13month-aged cheeses and one unaged cheese were analyzed for CLA concentration and isomer distribution. The CLA concentration in the fat of the aged and unaged cheeses ranged from 5.05 to 5.39 mg of CLA/g of fat. Isomers c-9,t-ll-/t-9,c-lland t-9,t-ll-/t-10,t-12-octadecadienoic acids accounted for 82-88 and 8-11 % of the total CLA, respectively. These results suggest that different starter cultures, processing conditions, and aging periods had negligible effects on the total CLA concentration but did influence the CLA isomer distribution in the cheeses studied.

Offspring of wild adult brown trout exposed to a range of Se concentrations were reared in a laboratory setting to primarily assess effects on survival and deformities. Maternal whole-body Se concentrations ranged from 4.7 to 22.6 mg/kg dry weight for wild fish. Corresponding Se concentrations in embryos ranged from 6.2 to 40.3 mg/kg dry weight. Significant relationships were found between embryo and whole-body tissue concentrations. Increasing egg Se concentrations were correlated with decreasing survival; however, hatch success was not significantly correlated with increasing embryo Se. The best fit effect concentration, 10% (EC10) for survival in the hatch to swim-up period was 20.6 mg/kg dry weight, and the EC10 for hatch to test termination at 88 d was 20.5 mg/kg dry weight egg Se. The best fit model for deformities was based on a baseline-adjusted severity index and resulted in an EC10 of 21.8 mg/kg dry weight egg Se. Both the best fit model EC10s represent more sensitive values than the published range of trout species EC10s. An egg to whole-body tissue conversion factor derived from the paired data resulted in a conversion factor for brown trout of 1.46, which resulted in a whole-body tissue EC10 of 14.04 mg/kg dry weight at an egg tissue EC10 of 20.5 mg/kg dry weight. Environ Toxicol Chem 2018;37:1396-1408. © 2018 SETAC.