Sampling household surfaces for pesticide residues: comparison between a press sampler and solvent-moistened wipes.

A modified Press Sampler was evaluated to determine the efficiency of pesticide transfer from household surfaces to collection disks as compared to wiping with a solvent-moistened gauze pad. Organophosphate (OP), pyrazole, and pyrethroid pesticides were applied to three hard flooring materials and carpet at two loading rates. Surfaces were dried and press sampled using C(18), 100% cotton or polyurethane foam (PUF) for either 2 or 10 min or wiped with isopropanol-moistened gauze pads.

Use of pharmacokinetic modeling to design studies for pathway-specific exposure model evaluation.

Validating an exposure pathway model is difficult because the biomarker, which is often used to evaluate the model prediction, is an integrated measure for exposures from all the exposure routes and pathways. The purpose of this article is to demonstrate a method to use pharmacokinetic (PK) modeling and computer simulation to guide the design of field studies to validate pathway models. The children's dietary intake model is discussed in detail as an example.

Transfer efficiencies of pesticides from household flooring surfaces to foods.

The transfer of pesticides from household surfaces to foods was measured to determine the degree of excess dietary exposure that occurs when children's foods contact contaminated surfaces prior to being eaten. Three household flooring surfaces (ceramic tile, hardwood, and carpet) were contaminated with an aqueous emulsion of commercially available pesticides (diazinon, heptachlor, malathion, chlorpyrifos, isofenphos, and cis- and trans-permethrin) frequently found in residential environments. A surface wipe method, as typically used in residential exposure studies, was used to measure the pesticides available on the surfaces as a basis for calculating transfer efficiency to the foods.

Using Thermocouples to Measure Temperatures during Retort or Autoclave Validation .

Thermocouples (TCs) are used almost exclusively in designing and validating the heat processes needed for sterilization of product in retorts or autoclaves. In this paper we discuss the vexing errors associated with using TCs in a hot, wet environment. Most problems seem to be associated with the action of steam and water on the TC lead wires and/or caused by temperature gradients on lead wire connectors.

Critical Factors for Thermal Processing of Institutional Pouches.

Institutional-sized pouches filled with whole kernel com in brine and condensed cream of celery soup were heated in a still retort. The sterilization values (F) and heat penetration parameters (j, f, f) were determined from temperature/time data as a function of the residual air in the horizontal pouches, pouch thickness, product fill, and circulation of the heating water. The F value for the soup was reduced from 11.