title: Fate of Escherichia coli O157:H7 as affected by pH or sodium chloride and in fermented, dry sausage.
abstract: The influence of pH adjusted with lactic acid or HCl or sodium chloride concentration on survival or growth of Escherichia coli O157:H7 in Trypticase soy broth (TSB) was determined. Studies also determined the fate of E. coli O157:H7 during the production and storage of fermented, dry sausage. The organism grew in TSB containing less than or equal to 6.5% NaCl or at a pH of 4.5 to 9.0, adjusted with HCl. When TSB was acidified with lactic acid, the organism grew at pH 4.6 but not at pH 4.5. A commercial sausage batter inoculated with 4.8 x 10(4) E. coli O157:H7 per g was fermented to pH 4.8 and dried until the moisture/protein ratio was less than or equal to 1.9:1. The sausage chubs were then vacuum packaged and stored at 4 degrees C for 2 months. The organism survived but did not grow during fermentation, drying, or subsequent storage at 4 degrees C and decreased by about 2 log10 CFU/g by the end of storage. These studies reveal the importance of using beef containing low populations or no E. coli O157:H7 in sausage batter, because when initially present at 10(4) CFU/g, this organism can survive fermentation, drying, and storage of fermented sausage regardless of whether an added starter culture was used.
authors.affiliation: Department of Food Microbiology and Toxicology, University of Wisconsin-Madison 53706.
authors.forename: K A
authors.initials: KA
authors.lastname: Glass
authors.forename: J M
authors.initials: JM
authors.lastname: Loeffelholz
authors.forename: J P
authors.initials: JP
authors.lastname: Ford
authors.forename: M P
authors.initials: MP
authors.lastname: Doyle
mesh_terms: D000818:Animals; D002417:Cattle; D004926:Escherichia coli / Q000254:growth & development*; D005285:Fermentation; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D008461:Meat Products; D012965:Sodium Chloride; D013552:Swine
chemical_list: D012965:Sodium Chloride