Aus der Arbeit der EPPO/OEPP (XIX)

Ohne ZusammenfassungPflanzenschutzorganisation für Europa und die Mittelmeerländer     

Rundschau

Ohne Zusammenfassung     

Comparison of diethyl ether and ethyl acetate as extracting agents for recovery of Ascaris spp. and Trichuris spp. eggs

Ethyl acetate and diethyl ether were compared for their ability to recover Ascaris spp. and Trichuris spp. eggs from seeded milorganite, liquid sludge, and cabbage. Concentrations of 10, 100, and 1000 eggs/10 g test sample were prepared for 20 replicates of each product. The use of diethyl ether yielded fewer eggs/10 g than did ethyl acetate in 5 of 6 sets of data. For Ascaris spp., recovery from cabbage was 10 times higher with ethyl acetate at the higher concentration than with diethyl ether. For Trichuris spp., recovery from liquid sludge was slightly higher with diethyl ether for all egg concentrations. The other results ranged from 0 to 23% difference in recovery for the 2 agents. Depending on the parasites in question and the products to be screened, the substitution of ethyl acetate for diethyl ether may be significant.     

Evaluation of an improved MPN medium for recovery of stressed and nonstressed Staphylococcus aureus

Two media used for recovery of foodborne Staphylococcus aureus were compared: trypticase soy broth with 10% salt (TSBS), used in the official AOAC method, and TSBS with 1% sodium pyruvate added (PTSB). Adding pyruvate increased recovery of 4 heat-stressed and nonstressed S. aureus foodborne strains from artificially contaminated mashed potato and ham salad substrates. The overall geometric means for the 2 media differed significantly at the alpha = 0.05 level. Recovery of S. aureus from 70 replicates of naturally contaminated Monterey Jack cheese was highest in PTSB. The overall geometric means/g were 63 in TSBS and 96 in PTSB.     

Gas chromatographic detection of D-(-)-2,3-butanediol and butyric acid produced by sporeformers in cream-style corn and canned beef noodle soup: collaborative study

A gas chromatographic method that identifies sporeformers as the cause of spoilage in swollen cans of low-acid foods was collaboratively studied in 2 stages. Two organic compounds produced by sporeformers, D-(-)-2,3-butanediol and butyric acid, are measured in the upper phase after centrifugation of the liquid portion of the can contents. Each sample is assayed on 2 packed columns designed for the assay of aqueous solutions of volatile fatty acids, using flame ionization detectors. For study 1, 16 duplicate inoculated cans of cream-style corn and beef noodle soup were sent to 9 collaborators. For study 2, 7 collaborators received 11 duplicate inoculated cans of the 2 foods. Duplicate uninoculated cans of each food served as negative controls. The inocula were 6 sporeforming organisms (4 Clostridium and 2 gas-forming Bacillus species) and 2 nonsporeformers. After the deletion of marginal samples, the percentages of correctly identified sporeformers and nonsporeformers in beef noodle soup were 83 (110/132) and 90 (54/60), respectively; corresponding percentages for cream-style corn were 80 (98/123) and 100 (35/35). The method has been adopted official first action.