An evaluation of the virulence and adherence properties of avian pathogenic .

Avian pathogenic (APEC) cause disease primarly in poultry; however, the link between APEC and infections in humans is questionable. In this current study, a total of 100 APEC strains isolated from chickens in Delmarva were evaluated for the presence of virulence genes to investigate their zoonotic potential in humans. A total of 28 isolates possessed one Enterohaemorrhagic (EHEC) virulence factor each and 87 isolates possessed up to 5 extraintestinal pathogenic (ExPEC) virulence factors.

Effect of bacterial cell-free supernatants on infectivity of norovirus surrogates.

Bacterial metabolic products were evaluated for inhibitory effects on viral propagation in cell culture. Cell-free supernatants (CFS) were prepared from growth of Enterococcus faecalis ATCC 19433, Pseudomonas fluorescens ATCC 13525, Escherichia coli 08, Staphylococcus epidermidis ATCC 12228, Bacillus subtilis 168, Bacillus coagulans 185A, B. coagulans 7050, Clostridium sporogenes PA3679, and a commercial probiotic mixture of Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium bifidum, Lactobacillus salivarius, and Streptococcus thermophilus in microbiological medium or milk.

Transmission of Clostridium difficile in foods.

Clostridium difficile is a human intestinal pathogen most frequently involved in diarrheal illnesses following the administration of antibiotics. There is growing concern that some C difficile infections (CDI) may be acquired from ingestion of C difficile spores in contaminated foods. The number of CDI cases is increasing with a heightening in the severity of disease symptoms and an increasing number of community-associated infections not connected to health care-associated risk.

Pathogenic psychrotolerant sporeformers: an emerging challenge for low-temperature storage of minimally processed foods.

Sporeforming bacteria are a significant problem in the food industry as they are ubiquitous in nature and capable of resisting inactivation by heat and chemical treatments designed to inactivate them. Beyond spoilage issues, psychrotolerant sporeformers are becoming increasingly recognized as a potential hazard given the ever-expanding demand for refrigerated processed foods with extended shelf-life. In these products, the sporeforming pathogens of concern are Bacillus cereus, Bacillus weihenstephanensis, and Clostridium botulinum type E.

Superdormant spores of bacillus species germinate normally with high pressure, peptidoglycan fragments, and bryostatin.

Superdormant spores of Bacillus cereus and Bacillus subtilis germinated just as well as dormant spores with pressures of 150 or 500 MPa and with or without heat activation. Superdormant B. subtilis spores also germinated as well as dormant spores with peptidoglycan fragments or bryostatin, a Ser/Thr protein kinase activator.

Viral Inactivation in Foods: A Review of Traditional and Novel Food-Processing Technologies.

  Over one-half of foodborne illnesses are believed to be viral in origin. The ability of viruses to persist in the environment and foods, coupled with low infectious doses, allows even a small amount of contamination to cause serious problems. An increased incidence of foodborne illnesses and consumer demand for fresh, convenient, and safe foods have prompted research into alternative food-processing technologies.

Use of nisin-coated plastic films to control Listeria monocytogenes on vacuum-packaged cold-smoked salmon.

Cold-smoked (Salmo salar) salmon samples were surface-inoculated with a cocktail of three nisin-resistant strains of L. monocytogenes (PSU1, PSU2 and PSU21) to a level of approximately 5 x 10(2) or 5 x 10(5) CFU/cm2 of salmon surface. The inoculated smoked salmon samples were vacuum-packaged with control film (no nisin) or nisin-coated plastic films and stored at either 4 or 10 degrees C.

Inactivation of hepatitis A virus by high-pressure processing: the role of temperature and pressure oscillation.

Inactivation of hepatitis A virus (HAV) in Dulbecco's modified Eagle medium with 10% fetal bovine serum was studied at pressures of 300, 350, and 400 MPa and initial sample temperatures of -10, 0, 5, 10, 20, 30, 40, and 50 degrees C. Sample temperature during pressure application strongly influenced the efficiency of HAV inactivation. Elevated temperature (> 30 degrees C) enhanced pressure inactivation of HAV, while lower temperatures resulted in less inactivation.

Inactivation of foodborne viruses of significance by high pressure and other processes.

The overall safety of a food product is an important component in the mix of considerations for processing, distribution, and sale. With constant commercial demand for superior food products to sustain consumer interest, nonthermal processing technologies have drawn considerable attention for their ability to assist development of new products with improved quality attributes for the marketplace. This review focuses primarily on the nonthermal processing technology high-pressure processing (HPP) and examines current status of its use in the control and elimination of pathogenic human viruses in food products.

Sensitivities of foodborne pathogens to pressure changes.

Eight foodborne pathogens were suspended in ultrahigh-temperature whole milk and treated at pressure levels of 0.1 to 690 MPa at 21.5 degrees C for 10 min.

Temperature and treatment time influence high hydrostatic pressure inactivation of feline calicivirus, a norovirus surrogate.

Interest in high hydrostatic pressure processing as a nonthermal pasteurization process for foods continues to increase. Feline calicivirus (FCV), a propagable virus that is genetically related to the nonpropagable human noroviruses, was used for detailed evaluation of the high pressure processing parameters necessary for virus inactivation. Pressure inactivation curves of FCV strain KCD in Dulbecco's modified Eagle medium with 10% fetal bovine serum were obtained at 200 and 250 MPa as a function of time at room temperature.

Factors influencing germination of Bacillus subtilis spores via activation of nutrient receptors by high pressure.

Different nutrient receptors varied in triggering germination of Bacillus subtilis spores with a pressure of 150 MPa, the GerA receptor being more responsive than the GerB receptor and even more responsive than the GerK receptor. This hierarchy in receptor responsiveness to pressure was the same as receptor responsiveness to a mixture of nutrients. The levels of nutrient receptors influenced rates of pressure germination, since the GerA receptor is more abundant than the GerB receptor and elevated levels of individual receptors increased spore germination by 150 MPa of pressure.

Inactivation of Salmonella typhimurium DT 104 in UHT whole milk by high hydrostatic pressure.

Cell suspensions of Salmonella typhimurium DT 104 in ultra-high temperature (UHT) whole milk were exposed to high hydrostatic pressure at 350, 400, 450, 500, 550, and 600 MPa at ambient temperature (ca. 21 degrees C). Tailing was observed in all survival curves, and sigmoidal survival curves were observed at relatively high pressure (500-600 MPa).

Pressure inactivation of hepatitis A virus in strawberry puree and sliced green onions.

Hepatitis A can be acquired by ingesting contaminated produce. To investigate the potential of high-pressure processing as an intervention strategy for virus in produce, strawberry puree and sliced green onions were inoculated with > 10(6) PFU of hepatitis A virus and treated with pressures ranging from 225 to 375 megapascals (MPa) in 25-MPa increments at ambient temperature. Subsequent virus extraction and plaque assay determined that hepatitis A virus was inactivated in strawberry puree and sliced green onions after 5-min exposures to pressures of 375 MPa with log PFU reductions of 4.

Inactivation of selected picornaviruses by high hydrostatic pressure.

The potential of high hydrostatic pressure processing (HPP) to inactivate Aichi virus (AiV), human parechovirus-1 (HPeV-1), and the coxsackievirus strains A9 and B5 was investigated. For coxsackievirus A9 (CAV9), a 5-min HPP treatment in minimum essential growth medium (MEM) supplemented with 10% fetal bovine sera (FBS) resulted in 3.4-, 6.

Pressure inactivation kinetics of phage lambda cI 857.

Inactivation curves of phage lambda cI 857 inactivated by high hydrostatic pressure were obtained at three pressure levels (300, 350, and 400 MPa) in buffered media and ultrahigh-temperature 2% reduced fat milk. Pressurization of phage lambda in buffered media at 300 MPa for 300 min, 350 MPa for 36 min, and 400 MPa for 8 min reduced the titer of phage lambda by 7.5, 6.

Pressure inactivation kinetics of Yersinia enterocolitica ATCC 35669.

The survival curves of Yersinia enterocolitica ATCC 35669 inactivated by high hydrostatic pressure were obtained at four pressure levels (300, 350, 400, and 450 MPa) in sodium phosphate buffer (0.1 M, pH 7.0) and four pressure levels (350, 400, 450, 500 MPa) in UHT whole milk.

Inactivation of hepatitis A virus and a calicivirus by high hydrostatic pressure.

Potential application of high hydrostatic pressure processing (HPP) as a method for virus inactivation was evaluated. A 7-log10 PFU/ml hepatitis A virus (HAV) stock, in tissue culture medium, was reduced to nondetectable levels after exposure to more than 450 MPa of pressure for 5 min. Titers of HAV were reduced in a time- and pressure-dependent manner between 300 and 450 MPa.

Concurrent Effects of High Hydrostatic Pressure, Acidity and Heat on the Destruction and Injury of Yeasts.

Saccharomyces cerevisiae ATCC 2373 and Zygosaccharomyces bailii ATCC 36947 were exposed to hydrostatic pressures ranging from 1,500 to 3,000 atmospheres for 10, 20 and 30 min in 0.1 M citrate buffer at pH 3.0, 4.

Fermentation Products from Carbohydrate Metabolism in Pediococcus pentosaceus PC39.

Pediococcus pentosaceus PC39 was grown in batch culture on selected hexoses and pentoses. The spent culture medium was analyzed by high performance liquid chromatography. Neither hexose metabolism nor pentose metabolism resulted in end-product patterns normally predicted for this organism based on its traditional classification.

A Bacteriocin Produced by Pediococcus Species Associated with a 5.5-Megadalton Plasmid.

Agarose gel electrophoresis of plasmid DNA and plasmid-curing experiments suggested that bacteriocin activity was harbored on a plasmid of approximately 5.5 megadaltons (Mdal) in Pediococcus acidilactici PO2, B5627 and PC, and Pediococcus pentosaceus MC-03. Bacteria that were sensitive to the bacteriocin included other pediococci, Leuconostoc mesenteroides , Streptococcus faecalis and Listeria monocytogenes .