Influence of curli expression by Escherichia coli 0157:H7 on the cell's overall hydrophobicity, charge, and ability to attach to lettuce.

Curli fibers are produced by some Escherichia coli cells in response to environmental stimuli. These extracellular proteins enhance the cell's ability to form biofilms on various abiotic surfaces. E.

Effects of modified atmosphere packaging on toxin production by Clostridium botulinum in raw aquacultured summer flounder fillets (Paralichthys dentatus).

Packaging fishery products under vacuum atmosphere packaging (VAC) and modified atmosphere packaging (MAP) conditions can significantly extend the shelf life of raw, refrigerated fish products. There is considerable commercial interest in marketing VAC and MAP refrigerated (never frozen) raw fish fillets. The objective of this study was to determine if Clostridium botulinum toxin development precedes microbiological spoilage in raw, refrigerated flounder fillets.

Efficacy of detergents in removing Salmonella and Shigella spp. from the surface of fresh produce.

Fresh produce has been implicated in several foodborne disease outbreaks. Produce surfaces can be primary sites of contamination during production and handling. One approach to reduce contamination is to treat fresh produce with rinsing agents.

Effect of organic acids and hydrogen peroxide on Cryptosporidium parvum viability in fruit juices.

Cryptosporidium parvum has historically been associated with waterborne outbreaks of diarrheal illness. Foodborne cryptosporidiosis has been associated with unpasteurized apple cider. Infectious oocysts are shed in the feces of common ruminants like cattle and deer in and near orchards.

Survivability of Salmonella and Shigella spp. in sodium lauryl sulfate and tween 80 at 22 and 40 degrees C.

Fresh produce has been implicated in several foodborne disease outbreaks. A primary site of contamination during production and handling is the surface of produce. One approach to reducing contamination is to treat fresh produce with rinsing agents.

Examination of attachment and survival of Toxoplasma gondii oocysts on raspberries and blueberries.

The consumption of Toxoplasma gondii oocysts on fresh produce may be a means of its transmission to humans. Cats shed T. gondii oocysts, which contaminate produce directly or contaminate water sources for agricultural irrigation and pesticide and fertilizer applications.

Antibacterial Effects of Hydrogen Peroxide and Methods for Its Detection and Quantitation .

Hydrogen peroxide is responsible for certain bactericidal effects observed in biological systems, such as growth inhibition of one bacterial species by another and killing of invading microorganisms by activated phagocytic cells. HO might be generated in bacteriological media by their exposure to light and/or oxygen and become an important mediator of toxic effects. HO cytotoxicity is apparently due to its capacity-generally mediated by transition metal ions-to generate more reactive and cytotoxic oxygen species such as the hydroxyl radical, which is a powerful oxidant, and which can initiate oxidation of biomolecules.

Effect of Heat Shock and Incubation Atmosphere on Injury and Recovery of Escherichia coli O157:H7.

Escherichia coli serotype O157:H7 cells were grown at 30°C for 6 h and subjected to a heat stress, or heat shock, at 42°C for 5 min. Heat-shocked and nonheat-shocked controls were heat treated at 55°C for up to 60 min. The number of injured cells was significantly higher in heat-shocked cells than in controls, and the rate of release of cell components was higher in heat-shocked cells.

Effect of Heat Shock and Growth Atmosphere on the Heat Resistance of Escherichia coli 0157:H7.

Log phase cells of Escherichia coli 0157:H7 were grown aerobically at 30°C and heat shocked at various time/temperature combinations to determine the optimum conditions that would result in the highest number of survivors to a subsequent 55°C heat treatment. Heat shocking at 42°C for 5 min resulted in the largest increase in D value over nonheat-shocked controls of all heat-shock time/temperature combinations tested. Growth atmosphere significantly contributed to the heat resistance of both heat-shocked and nonheat-shocked cells, with anaerobically grown cells having D values higher than those of cells grown aerobically.

Sodium Hypophosphite Inhibition of the Growth of Selected Gram Negative Foodborne Pathogenic and Spoilage Bacteria.

Sodium hypophosphite was evaluated for inhibition of growth of selected gram negative foodborne pathogenic and spoilage bacteria in laboratory media. In addition, the effects of pH and sodium chloride alone and in combination with sodium hypophosphite were examined. All inhibition studies were performed with optimal or nearly optimal growth conditions for each bacterium.

Influence of pH and Phosphate Buffer on Inhibition of Clostridium botulinum by Antioxidants and Related Phenolic Compounds.

The compounds butylated hydroxyanisole (BHA); butylated hydroxytoluene (BHT); tert-butylhydroquinone (TBHQ); nor-dihydroguaiaretic acid (NDGA); 2', 4', 5'-trihydroxybutyrophenone (THBP); 8-hydroxyquinoline; isoamyl and isobutyl esters of gallic acid; ethyl, propyl, and butyl esters of p-hydroxybenzoic acid; thymol; 2-isopropylphenol; 2-tert-butylphenol; and 2-tert-butyl-4-methylphenol were tested for their antibotulinal activity in prereduced Thiotone-yeast extract-glucose (TYG) broth with and without hosphate buffer (0.05 M, pH 6.0 and 7.

Inhibition and Control of Bacterial Spore Germination.

Factors affecting germination of bacterial spores as well as chemical inhibition of germination are reviewed. Current theories on the nature of initiation of the germination process are also presented. Transformation of a dormant bacterial spore into a metabolically active vegetative cell involves a myriad of complex biochemical events of which the "trigger reaction" is thought to be the prime event.