Control of Escherichia coli O157:H7 in large-diameter, Lebanon-style bologna (1998)

Abstract

Lebanon bologna raw batter was mixed time fermentation process, but is susceptible with a five-strain mixture of Escherichia coli to E. coli O157:H7 contamination. An availO157:H7 to achieve average inoculum levels able medium is sensitive to recovering heatof 7.79, 7.77, and 7.92 log CFU/g as deterinjured cells. Therefore, the objectives of this mined on MSA, 202, and PRSA media, study were: 1) to determine the effects of respectively. Treatment 1 consisted of a typical thermal processing temperatures and fermentation cycle of 8 hrs at an internal times for Lebanon bologna on reducing E. temperature (I.T.) of 80EF then 24 hrs at coli O157:H7 and 2) to evaluate the effec100EF I.T., followed by 24 hrs at 110EF I.T. tiveness of MacConkey Sorbitol Agar Treatments 2, 3, and 4 included additional (MSA), 202 agar, and Phenol Red Agar with heating at 115EF I.T. for 1, 2, and 5 hrs, 1% sorbitol (PRSA) for detecting E. coli respectively. All heat treatments resulted in O157:H7. product that was negative (<1.9 log CFU/g detection limit) on all culture media and negative after enrichment on mEC selective medium. This study validates that a five-log Five different isolates of E. coli O157:H7 reduction of E. coli O157:H7 can be were used. Two were human isolates, and achieved using the described protocol, thus the others were of meat origin, one being meeting USDA/FSIS requirements. implicated in the 1995 salami outbreak.