ISOLATION OF BDELLOVIBRIOS THAT PREY ON ESCHERICHIA COLI O157:H7 AND SALMONELLA SPECIES AND APPLICATION FOR REMOVAL OF PREY FROM STAINLESS STEEL SURFACES

Biofilms are a mixture of bacteria and extracellular products secreted by bacterial cells and are of great concern to the food industry because they offer physical, mechanical, and biological protection to bacterial cells. This study was conducted to quantify biofilms formed by different Shiga toxin–producing Escherichia coli (STEC) strains on polystyrene and stainless steel surfaces and to determine the effectiveness of sanitizing treatments in control of these biofilms. STEC producing various amounts of cellulose (n = 6) or curli (n = 6) were allowed to develop biofilms on polystyrene and stainless steel surfaces at 28°C for 7 days. The biofilms were treated with 2% acetic or lactic acid and manufacturer-recommended concentrations of acidic or alkaline sanitizers, and residual biofilms were quantified. Treatments with the acidic and alkaline sanitizers were more effective than those with the organic acids for removing the biofilms. Compared with their counterparts, cells expressing a greater amount of cellulose or curli formed more biofilm mass and had greater residual mass after sanitizing treatments on polystyrene than on stainless steel. Research suggests that the organic acids and sanitizers used in the present study differed in their ability to control biofilms. Bacterial surface components and cell contact surfaces can influence both biofilm formation and the efficacy of sanitizing treatments. These results provide additional information on control of biofilms formed by STEC.

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Synergistic effect of steam and lactic acid against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilms on polyvinyl chloride and stainless steel

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2012.05.006 ◽

2012 ◽

Vol 157 (2) ◽

pp. 218-223 ◽

Cited By ~ 21

Author(s):

Ga-Hee Ban ◽

Sang-Hyun Park ◽

Sang-Oh Kim ◽

Sangryeol Ryu ◽

Dong-Hyun Kang

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

Lactic Acid ◽

Listeria Monocytogenes ◽

Synergistic Effect ◽

Salmonella Typhimurium ◽

Polyvinyl Chloride ◽

Escherichia Coli O157

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Effects of UV Irradiation on Selected Pathogens in Peptone Water and on Stainless Steel and Chicken Meat

Journal of Food Protection ◽

10.4315/0362-028x-65.7.1142 ◽

2002 ◽

Vol 65 (7) ◽

pp. 1142-1145 ◽

Cited By ~ 52

Author(s):

T. KIM ◽

J. L. SILVA ◽

T. C. CHEN

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

Listeria Monocytogenes ◽

Uv Irradiation ◽

Processing Time ◽

Chicken Meat ◽

Escherichia Coli O157 ◽

Uv Treatment ◽

E Coli ◽

Peptone Water

Effects of intensity and processing time of 254 nm UV irradiation on Listeria monocytogenes, Escherichia coli O157: H7, and Salmonella Typhimurium were investigated. Intensities measured at 5.08, 10.1, 15.2, and 20.3 cm from the light source were 1,000, 500, 250, and 150 μW/cm2, respectively. Intensities of 250 or 500 μW/cm2 reduced all suspended pathogen cells in peptone water about 5 log cycles after 2 min and completely inactivated L. monocytogenes and E. coli O157:H7 after 3 min by reductions of 8.39 and 8.64 log cycles, respectively. Intensities of 250 or 500 μW/cm2 also reduced (P ≤ 0.05) the tested pathogens inoculated on stainless steel (SS) chips, and E. coli O157:H7 was completely destroyed at 500 μW/cm2 for 3 min. After UV treatment for 3 min at 500 μW/cm2, all selected pathogens on chicken meat with or without skin showed reduction ranges from 0.36 to 1.28 log cycles. Results demonstrated that UV irradiation could effectively decrease pathogens in peptone water and on SS but that it was less effective on chicken meat.

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