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Growth temperature of four Campylobacter jejuni strains influences their subsequent survival in food and water Full text
2006
Duffy, L. | Dykes, G.A.
To determine if Campylobacter jejuni grown at 37 and 42 °C have different abilities to survive on beef and chicken, and in water. Beef, chicken and water were separately inoculated with four Camp. jejuni (two poultry and two beef) strains grown at 37 or 42 °C. The matrices were stored at ~4 °C and Camp. jejuni numbers were monitored over time by plate counts. On beef there was a greater decrease in number for two strains (P < 0·05; ~0·7 and 1·3 log CFU cm⁻²) grown at 37 °C as compared with 42 °C. By contrast on chicken there was a decrease in numbers for two strains (P < 0·05; ~1·3 and 1 log CFU g⁻¹) grown at 42 °C as compared with 37 °C. In water there was a greater decrease in numbers for all strains (P < 0·05; ~3-5·3 log CFU ml⁻¹) grown at 42 °C as compared with 37 °C. Growth temperature influences the survival of Camp. jejuni on food and in water. Campylobacter jejuni survival studies need to consider growth temperature to avoid erroneous results. Campylobacter jejuni grown at 37 °C, the body temperature of humans and cattle, may represent a greater public health risk in water than those grown at 42 °C, the body temperature of poultry.
Show more [+] Less [-]Detection of small numbers of Campylobacter jejuni and Campylobacter coli cells in environmental water, sewage, and food samples by a seminested PCR assay
1999
Waage, A.S. | Vardund, T. | Lund, V. | Kapperud, G.
A rapid and sensitive assay was developed for detection of small numbers of Campylobacter jejuni and Campylobacter coil cells in environmental water, sewage, and food samples. Water and sewage samples were filtered, and the filters were enriched overnight in a nonselective medium. The enrichment cultures were prepared for PCR by a rapid and simple procedure consisting of centrifugation, proteinase K treatment, and boiling. A seminested PCR based on specific amplification of the intergenic sequence between the two Campylobacter flagellin genes, flaA and flaB, was performed, and the PCR products were visualized by agarose gel electrophoresis. The assay allowed us to detect 3 to 15 CFU of C. jejuni per 100 ml in water samples containing a background flora consisting of up to 8,700 heterotrophic organisms per ml and 10,000 CFU of coliform bacteria per 100 ml. Dilution of the enriched cultures 1:10 with sterile broth prior to the PCR was sometimes necessary to obtain positive results. The assay was also conducted with food samples analyzed with or without overnight enrichment. As few as less than or equal to 3 CFU per g of food could be detected with samples subjected to overnight enrichment, while variable results were obtained for samples analyzed without prior enrichment. This rapid and sensitive nested PCR assay provides a useful tool for specific detection of C. jejuni or C. coli in drinking water, as well as environmental water, sewage, and food samples containing high levels of background organisms.
Show more [+] Less [-]Efficacy of Neutral Electrolyzed Water, Quaternary Ammonium and Lactic Acid‐Based Solutions in Controlling Microbial Contamination of Food Cutting Boards Using a Manual Spraying Technique Full text
2016
Al‐Qadiri, Hamzah M. | Ovissipour, Mahmoudreza | Al‐Alami, Nivin | Govindan, Byju N. | Shiroodi, Setareh Ghorban | Rasco, Barbara
Bactericidal activity of neutral electrolyzed water (NEW), quaternary ammonium (QUAT), and lactic acid‐based solutions was investigated using a manual spraying technique against Salmonella Typhimurium, Escherichia coli O157:H7, Campylobacter jejuni, Listeria monocytogenes and Staphylococcus aureus that were inoculated onto the surface of scarred polypropylene and wooden food cutting boards. Antimicrobial activity was also examined when using cutting boards in preparation of raw chopped beef, chicken tenders or salmon fillets. Viable counts of survivors were determined as log₁₀ CFU/100 cm² within 0 (untreated control), 1, 3, and 5 min of treatment at ambient temperature. Within the first minute of treatment, NEW and QUAT solutions caused more than 3 log₁₀ bacterial reductions on polypropylene surfaces whereas less than 3 log₁₀ reductions were achieved on wooden surfaces. After 5 min of treatment, more than 5 log₁₀ reductions were achieved for all bacterial strains inoculated onto polypropylene surfaces. Using NEW and QUAT solutions within 5 min reduced Gram‐negative bacteria by 4.58 to 4.85 log₁₀ compared to more than 5 log₁₀ reductions in Gram‐positive bacteria inoculated onto wooden surfaces. Lactic acid treatment was significantly less effective (P < 0.05) compared to NEW and QUAT treatments. A decline in antimicrobial effectiveness was observed (0.5 to <2 log₁₀ reductions were achieved within the first minute) when both cutting board types were used to prepare raw chopped beef, chicken tenders or salmon fillets.
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