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Health claims for barley β-glucan (BG) have prompted the development of food products containing barley; however, some new products (such as milled grain used without a cook step, as in a smoothie) do not use any form of heat treatment during processing or prior to consumption, which could affect microbial safety and potential health benefits. The aims of this research were to evaluate current commercial barley products for microbial counts and BG characteristics and to determine the effects of different heat treatments on these attributes in whole grain barley samples. Three heat treatments (micronization, roasting, and conditioning) were performed on three cultivars of barley (CDC Rattan, CDC McGwire, and CDC Fibar). The microbial quality was measured with standard plate count (SPC), mold and yeast count (MYC), and coliforms or Escherichia coli. Only four of the 17 commercial barley products tested met acceptable microbial limits used in this study. All three heat treatments applied to the barley sample...

The effect of Bifidobacterium breve on the survival and growth of Enterobacter sakazakii in rehydrated infant milk formula stored at 4–45C was studied. A commercial culture of B. breve and a five-strain cocktail E. sakazakii were mixed with rehydrated formula and stored up to 8 h. The populations of B. breve and E. sakazakii at each storage time/temperature were determined. There was a two-way interactive effect between B. breve numbers and temperature on the number of E. sakazakii in the rehydrated formula at 3–8 h of storage. E. sakazakii did not grow in the rehydrated formula at 4C. At 12 and 20C, the numbers of E. sakazakii in the presence of B. breve were lower than those in the formula without B. breve at 8 h of storage, and at 45C, when the bacteria were combined, a similar result was obtained at 6- and 8-h storage. The presence of B. breve in the formula appeared to enhance the growth of E. sakazakii at 37C in the rehydrated formula stored at 2–8 h. Other more competitive inhibitory probiotic cultures would be more appropriate to control E. sakazakii growth in unrefrigerated rehydrated milk-based formula. PRACTICAL APPLICATIONS Results obtained showed that the probiotic organisms Bifidobacterium breve did not reduce Enterobacter sakazakii levels in rehydrated infant formula if held >2 h at >30C. At 37C, B. breve stimulated the growth of the pathogen after 2 h. Choice of probiotic bacteria for inclusion in these products to improve infant gut microflora should be based on their neutral or negative influence on E. sakazakii survival/growth to reduce the risk to health associated with the contamination of these products during manufacture.

Increasing the growth performance of broiler chickens by supplementing their diets with exogenous enzymes can also contribute to positive changes in gut health. In this respect the growth of various bacteria normally associated with the gastrointestinal tract of poultry was assessed in vitro using a medium containing arabinoxylan, β-glucan, guar gum and raffinose and their corresponding enzymes. Overall, enzymes releasing the largest amounts of free sugars yielded the largest increase in bacterial numbers. Accordingly, β-glucan and raffinose treated with their respective enzymes promoted the largest number of bacterial types, reaching a minimum of 1.0 log10 population within 6 h at 40 °C. A broiler chicken growth trial was also conducted using wheat-, barley- and corn-based diets with and without enzyme and probiotic addition. Escherichia coli, coliforms, enterococci and aerobic and anaerobic sporeformers were monitored for growth in both the caecum and ileum. Enzyme supplementation reduced E. coli levels in the caecum of broilers fed wheat- or corn-based diets. A further reduction in E. coli numbers was observed in broilers fed the same diets supplemented with a combination of enzyme and probiotic. Enzyme supplementation had much less of an effect on microbial populations in the ileum. Inclusion of probiotics reduced E. coli levels in the caecum and ileum but only in broilers fed wheat- and corn-based diets. Anaerobic spore levels in the ileum increased in all diets containing probiotic. Overall, inclusion of enzymes or probiotics exhibited mixed effects on gut bacteria, depending on the nature of the carbohydrate source and enzyme. Copyright © 2007 Society of Chemical Industry

Pre-cooked roast beef slices were stored 28 days at 4 +/- 2 degrees C in air or 100% N2 with and without vaporized horseradish essential oil (HEO). Addition of 20 microliter HEO/L restricted growth of most spoilage bacteria. Pseudomonas spp. and Enterobacteriaceae were strongly inhibited by HEO. Lactic acid bacteria were more resistant to the antimicrobial effect and dominated spoilage flora. Sensory evaluation and headspace analysis by gas chromatography/mass spectrometry revealed that development of off-flavors and odors derived from fat oxidation products was delayed by HEO. Cooked meat color was also preserved in samples stored under HEO.

Microtitre plate nucleic acid probe hybridization systems were developed for the detection of thermophilic Campylobacter and Campylobacter jejuni. Specific RNA probes obtained by in vitro transcription of DNA templates synthesized by polymerase chain reaction using two sets of specific primers incorporating bacteriophage T7 promoter sequences were immobilized on a microtitre plate. The hybridizations were carried out on samples of genomic DNA sheared by ultrasonication. Optimum conditions for the ultrasonic treatment were determined in order to obtain the highest degree of hybridization with immobilized RNA probe. Finally, detection of RNA-DNA hybrids in the wells was accomplished by an immunoenzymatic assay using a monoclonal anti-RNA-DNA hybrid antibody. This rapid, simple hybridization and immunoenzymatic assay system will facilitate the detection of Campylobacter in foods and clinical samples.

Wrapped boneless pork loin roasts and slices were stored at 4 o C in bulk under constant CO 2 concentrations of 50% and 100% for 1 and 2 wks. Samples stored under 50% CO 2 for 2 wks could subsequently be displayed (aerobic) for 3 days without becoming unacceptable or for 6 days if previously held under 100% CO 2 for 14 days. Aerobic shelf-life at 4 o C of the latter samples equalled that of fresh pork chops under simulated retail display. Physicochemical characteristics during storage did not limit acceptability. Reusable master packs have application for distribution of retail ready cuts under controlled atmosphere packaging