title: Sublethal sanitizer stress and adaptive response of Escherichia coli O157:H7.
abstract: The effect of sublethal exposure to peroxyacetic acid (PAA) sanitizer on adaptation to peroxidative stress and development of thermal cross-resistance was investigated in Escherichia coli O157:H7. Acute sublethal PAA sanitizer exposure was used to represent a contact scenario. Cultures were grown in Trypticase soy-yeast extract broth. Acute treatment cultures were pretreated with 0.1% PAA, then all cultures were challenged at either 80 mM H202 or 54 degrees C. Acute and peroxide control cultures showed substantially increased peroxidative tolerance (D80mM > 2 h) versus negative control cultures not exposed to sanitizer (D80mM = 0.19+/-0.03 h). The inactivation rate of the acetic acid control (D80mM = 0.21+/-0.05 h) was similar to the negative control rate. Acute (D54 degrees C = 0.55+/-0.07 h) cultures did not exhibit increased thermal resistance versus the control (D54 degrees C = 0.54+/-0.07 h). Thermal injury was determined as difference in D54 degrees C value (deltaD54 degrees c) obtained on pyruvate and deoxycholate media. Thermal-induced injury was not observed in either control (deltaD54 degrees C = 0.04 h) or acute (deltaD54 degrees C = 0.05 h) cultures.
authors.affiliation: The Department of Food Science and Nutrition, The University of Minnesota, St. Paul 55108, USA. zook0002@tc.umn.edu
authors.forename: C D
authors.initials: CD
authors.lastname: Zook
authors.forename: F F
authors.initials: FF
authors.lastname: Busta
authors.forename: L J
authors.initials: LJ
authors.lastname: Brady
mesh_terms: D015169:Colony Count, Microbial; D003470:Culture Media; D004202:Disinfectants / Q000494:pharmacology*; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development*; D005511:Food Handling / Q000379:methods; D005519:Food Preservation; D006358:Hot Temperature; D006861:Hydrogen Peroxide; D010463:Peracetic Acid / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D004202:Disinfectants; D006861:Hydrogen Peroxide; D010463:Peracetic Acid