The gastric stomach of humans is a barrier to food-borne pathogens, but Escherichia coli can survive at pH 2.0 if it grown under mildly acidic conditions. Cattle are natural reservoir for pathogenic E. coli, and cattle fed mostly grain had lower colonic more acid-resistant than only hay. On the basis numbers survival after acid shock, that were 10(6)-fold hay, brief period hay feeding decreased count substantially.

Batch cultures of Escherichia coli K-12 grew well in an anaerobic glucose medium at pH 5.9, but even small amounts acetate (20 mM) inhibited growth and fermentation. E. O157:H7 was least fourfold more resistant to than K-12. Continuous (pH dilution rate 0.085 h -1 ) did not wash out until the sodium concentration input 80 mM, whereas persisted 160 mM. cells accumulated as much 500 mM acetate, intracellular never greater 300 Differences accumulation could be explained by transmembrane...

An increasing number of outbreaks gastroenteritis recently caused by Escherichia coli O157:H7 have been linked to the consumption leafy green vegetables. Although it is known that E. survives and grows in phyllosphere lettuce plants, molecular mechanisms which this bacterium associates with plants are largely unknown. The goal study was identify genes relevant its interaction, survival, or attachment leaf surfaces, comparing K-12, a model system, O157:H7, pathogen associated large outbreaks....

The objective of this study was to isolate, identify and characterize a collection lytic bacteriophages capable infecting enterohaemorrhagic Escherichia coli (EHEC) serotypes.Phages were isolated from dairy cattle feedlot manure using E. O157, O26 O111 strains as hosts. Phages enriched faecal slurries by culture in 10× trypticase soy broth at 37°C overnight. Phage plaques obtained mixing the filtered supernatant with molten tryptone agar containing phage host strain, pouring inoculated on...

A "two-step" aptamer-based surface-enhanced Raman scattering (SERS) detection assay was developed for ricin in liquid foods. Ricin B chain first captured out of food matrices by aptamer-conjugated silver dendrites and then the spectrum directly read on dendrites. Aptamer use this promotes ease manipulation as well improved sensitivity compared to antibody-based approaches. The limit 10 ng mL−1 phosphate buffered saline (PBS), 50 orange juice, 100 milk based principal component analysis (PCA)...

Salmonella can survive for long periods under extreme desiccation conditions. This stress tolerance poses a risk food safety, but relatively little is known about the molecular and cellular regulation of this adaptation mechanism. To determine genetic components involved in Salmonella's response to desiccation, we performed global transcriptomic analysis comparing S. enterica serovar Typhimurium cells equilibrated low water activity (aw 0.11) high 1.0). The revealed that 719 genes were...

ABSTRACT A cattle trial using artificially inoculated calves was conducted to determine the effect of addition colicinogenic Escherichia coli strains capable producing colicin E7 (a 61-kDa DNase) feed on fecal shedding serotype O157:H7. The experiment divided into three periods. In period 1, which lasted 24 days, six were used as controls, and eight received 10 7 CFU E. mixture strains) per g feed. Both groups orally with nalidixic acid-resistant O157:H7 days after treatment started. periods...

Salmonella and enterohemorrhagic Escherichia coli (EHEC) are of serious concern in wheat flour its related products but little is known on their survival thermal death kinetics. This study was undertaken to determine long-term viability inactivation kinetics flour. Inoculation performed using mixtures EHEC serogroups O45, O121, O145 followed by storage at room temperature (23°C) or 35°C (for Salmonella). Plate counting tryptic soy agar (TSA) enrichment were used assess survival. For studies,...

Environmental contamination of ready-to-eat (RTE) foods with Listeria monocytogenes is a major food safety concern. Treatment surfaces antimicrobial blue light (aBL) has recently emerged as technology that can supplement current sanitation practices. Chemical sanitizers are used extensively by the industry, but their combination aBL at 405 nm not been evaluated. This project was undertaken to determine combined effect inactivate L. dried cells on inert surfaces. Peracetic acid (PAA),...

The objective of this study was to investigate alkaline treatments cattle manure kill coliforms, Escherichia coli O157:H7 and Salmonella Typhimurium DT104 based on their inhibition by carbonate ion ammonia.Pure cultures S. E. strains were treated with sodium ammonia determine threshold inhibitory concentrations. Fresh samples inoculated the same survival determined after addition hydroxide, ammonium sulphate, and/or urea. Control CO NH3 concentrations in pH adjustment 9.5 hydroxide more than...

Escherichia coli strains were screened for their ability to inhibit E. O157:H7. An initial evaluation of 18 carrying previously characterized colicins determined that only colicin E7 inhibited all the O157:H7 tested. A total 540 had recently been isolated from humans and nine different animal species (cats, cattle, chickens, deer, dogs, ducks, horses, pigs, sheep) tested by a flip-plating technique. Approximately 38% these found noncolicinogenic K12 strains. The percentage potentially...