Biomedical subjects

Vickery A Brewer

Publications and source records attributed to Vickery A Brewer.

3 recordsLinked to original sources

PubMedDate not supplied

Preparation of peanut butter suspension for determination of peanuts using enzyme-linked immunoassay kits.

Peanuts are one of the 8 most common allergenic foods and a large proportion of peanut-allergic individuals have severe reactions, some to minimal exposure. Specific protein constituents in the peanuts are the cause of the allergic reactions in sensitized individuals who ingest the peanuts. To avoid accidental ingestion of peanut-contaminated food, methods of analysis for the determination of the allergenic proteins in foods are important tools. Such methods could help identify foods inadvertently contaminated with peanuts, thereby reducing the incidence of allergic reactions to peanuts. Commercial immunoassay kits are available but need study for method performance, which requires reference materials for within- and between-laboratory validations. In this study, National Institute of Standards and Technology Standard Reference Material 2387 peanut butter was used. A polytron homogenizer was used to prepare a homogenous aqueous Peanut Butter suspension for the evaluation of method performance of some commercially available immunoassay kits such as Veratox for Peanut Allergen Test (Neogen Corp.), Ridascreen Peanut (R-Biopharm GmbH), and Bio-Kit Peanut Protein Assay Kit (Tepnel). Each gram of the aqueous peanut butter suspension contained 20 mg carboxymethylcellulose sodium salt, 643 microg peanut, 0.5 mg thimerosal, and 2.5 mg bovine serum albumin. The suspension was homogenous, stable, reproducible, and applicable for adding to ice cream, cookies, breakfast cereals, and chocolate for recovery studies at spike levels ranging from 12 to 90 microg/g.

Arachis↗

PubMedDate not supplied

Variation of analytical results for peanuts in energy bars and milk chocolate.

Peanuts contain proteins that can cause severe allergic reactions in some sensitized individuals. Studies were conducted to determine the percentage of recovery by an enzyme-linked immunosorbent assay (ELISA) method in the analysis for peanuts in energy bars and milk chocolate and to determine the sampling, subsampling, and analytical variances associated with testing energy bars and milk chocolate for peanuts. Food products containing chocolate were selected because their composition makes sample preparation for subsampling difficult. Peanut-contaminated energy bars, noncontaminated energy bars, incurred milk chocolate containing known levels of peanuts, and peanut-free milk chocolate were used. A commercially available ELISA kit was used for analysis. The sampling, sample preparation, and analytical variances associated with each step of the test procedure to measure peanut protein were determined for energy bars. The sample preparation and analytical variances were determined for milk chocolate. Variances were found to be functions of peanut concentration. Sampling and subsampling variability associated with energy bars accounted for 96.6% of the total testing variability. Subsampling variability associated with powdered milk chocolate accounted for >60% of the total testing variability. The variability among peanut test results can be reduced by increasing sample size, subsample size, and number of analyses. For energy bars the effect of increasing sample size from 1 to 4 bars, subsample size from 5 to 20 g, and number of aliquots quantified from 1 to 2 on reducing the sampling, sample preparation, and analytical variance was demonstrated. For powdered milk chocolate, the effects of increasing subsample size from 5 to 20 g and number of aliquots quantified from 1 to 2 on reducing sample preparation and analytical variances were demonstrated. This study serves as a template for application to other foods, and for extrapolation to different sizes of samples and subsamples as well as numbers of analyses.

Allergens↗

PubMedDate not supplied

Performance Tested Method multiple laboratory validation study of ELISA-based assays for the detection of peanuts in food.

Performance Tested Method multiple laboratory validations for the detection of peanut protein in 4 different food matrixes were conducted under the auspices of the AOAC Research Institute. In this blind study, 3 commercially available ELISA test kits were validated: Neogen Veratox for Peanut, R-Biopharm RIDASCREEN FAST Peanut, and Tepnel BioKits for Peanut Assay. The food matrixes used were breakfast cereal, cookies, ice cream, and milk chocolate spiked at 0 and 5 ppm peanut. Analyses of the samples were conducted by laboratories representing industry and international and U.S governmental agencies. All 3 commercial test kits successfully identified spiked and peanut-free samples. The validation study required 60 analyses on test samples at the target level 5 microg peanut/g food and 60 analyses at a peanut-free level, which was designed to ensure that the lower 95% confidence limit for the sensitivity and specificity would not be <90%. The probability that a test sample contains an allergen given a prevalence rate of 5% and a positive test result using a single test kit analysis with 95% sensitivity and 95% specificity, which was demonstrated for these test kits, would be 50%. When 2 test kits are run simultaneously on all samples, the probability becomes 95%. It is therefore recommended that all field samples be analyzed with at least 2 of the validated kits.

Allergens↗