Monitoring acetylcholinesterase levels in migrant agricultural workers and their children using a portable test kit.

The EQM Research, Inc., portable test kit was evaluated as a surveillance tool for blood cholinesterase levels among migrant workers and their children. Laboratory validation demonstrated a linear relationship between the reference Ellman and kit methods (Ellman = 0.95 x kit result + 0.82, r2 = 0.98). Pre- and post-season cholinesterase levels measured in 70 farm workers were within normal ranges, but significantly different at 28.5 and 29.7 U/g Hb, respectively (paired t-test, p = 0.014). Results from 98 migrant farm worker children and a comparison group of 53 age-matched non-agricultural children showed that cholinesterase levels were not significantly different between the agricultural and non-agricultural children (ANOVA, p = 0.69). These data demonstrate that a portable test kit can provide useful data pesticide exposures when measurements are made in a temperature-controlled setting.

Survey of vitamin content of fortified milk.

This paper summarizes work done by 4 different laboratories on the vitamin content of milk. Riboflavin, vitamin A, and vitamin D were assayed in whole, 2%, and skim milks that had been fortified. In general, the adherence to label claim decreased with decreasing fat content. This may be due to methods and stage of vitamin addition prior to processing.

Reverse phase liquid chromatographic determination of vitamins D2 and D3 in milk.

A single column reverse phase high pressure liquid chromatographic method is described for the determination of vitamins D2 and D3 in fluid milk. Resolution of vitamin D2 from D3 is helpful for use as an internal standard. The method involves overnight saponification at room temperature, extraction of unsaponifiables, precipitation of cholesterol, and aluminum oxide column cleanup. Sample extracts were chromatographed under isocratic conditions on a 10 micron Vydac reverse phase column using acetonitrile-methanol (90 + 10) as the mobile phase. In addition, a MicroPak MCH-5 reverse phase column with acetonitrile as the mobile phase was used with an automatic system for one product type. Thirty samples each of homogenized (3.8% fat), low fat (2.0% fat), and skim (less than or equal to 0.5% fat) milk spiked with 200, 400, and 600 IU vitamin D/qt were analyzed. Coefficient of variation (CV) and percent recovery for each product type and each spike level of vitamins D2 and D3 were calculated from 10 replicate analyses. Vitamin D2 recoveries for all product types at the 3 fortification levels varied from 85.2 to 99.7%; vitamin D3 recoveries varied from 85.9 to 98.8%. The minimum detectable quantity of vitamin D in milk was 15 IU/qt.