title: Reduction of Escherichia coli O157:H7 and Salmonella after application of various sanitizing treatments to harvesting knives.
abstract: Consumption of food contaminated with Escherichia coli O157:H7 and Salmonella can cause enteric disease in consumers. If not properly sanitized, knives used during animal harvest can spread these and other pathogens. This study evaluated the reduction of E. coli  O157:H7 and Salmonella on harvesting knives after nonthermal sanitation. Knives were inoculated in cocktails of E. coli O157:H7 or Salmonella and treated by 30-s immersions in ambient-temperature solutions (unless temperature was specified) of 1.1 % sodium metasilicate  (SMS), 200 ppm of quaternary ammonium compounds (QAC), 200 ppm of chlorine (Cl(2)), 5 % lactic acid (LA), 82.2°C water, and 21°C water. Initial and treated counts were determined by plating onto MacConkey and xylose lysine desoxycholate for E. coli O157:H7 and Salmonella,  respectively. Initial counts were determined by sampling one side of the knife blade, while treated counts were sampled from the opposite side. Plates were incubated for 24 to 48 h at 37°C. Mean attachment of E. coli O157:H7 and Salmonella was 4.51 and 5.09 log CFU/cm(2),  respectively. Mean log reductions on knives inoculated with E. coli O157:H7 were 1.16, 3.51, 3.38, 1.38, 3.82, and 2 0.41 CFU/cm(2) after treatment in SMS, QAC, Cl(2), LA, 82.2°C water, and 21°C water, respectively (P ≤ 0.05). Knives inoculated with  Salmonella showed reductions of 0.78, 3.42, 3.40, 2.91, 4.12, and 0.36 log CFU/cm(2) after treatment in SMS, QAC, Cl(2), LA, 82.2°C water, and 21°C water, respectively (P ≤ 0.05). Results indicate that some ambient-temperature sanitizing agents have  the potential to significantly reduce E. coli O157:H7 and Salmonella populations on knives used during animal harvest.
authors: Department of Animal and Food Sciences, Texas Tech University, Box 42141, Lubbock, TX 79409, USA.
authors: W N
authors: WN
authors: Tapp
authors: S E
authors: SE
authors: Gragg
authors: J C
authors: JC
authors: Brooks
authors: M F
authors: MF
authors: Miller
authors: M M
authors: MM
authors: Brashears
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development*; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control*; D005511:Food Handling / Q000379:methods / Q000592:standards; D005516:Food Microbiology; D006801:Humans; D012475:Salmonella / Q000187:drug effects / Q000254:growth & development*; D012499:Sanitation / Q000379:methods / Q000592:standards; D013696:Temperature
chemical_list: D000890:Anti-Infective Agents