Not-ready-to-eat breaded chicken products formulated with antimicrobial ingredients were tested for the effect of sample dimensions, surface browning method and final internal sample temperature on inoculated Salmonella populations. Fresh chicken breast meat portions (5 × 5 × 5 cm), inoculated with Salmonella (7-strain mixture; 5 log CFU/g), were mixed with (5% v/w total moisture enhancement) (i) distilled water (control), (ii) caprylic acid (CAA; 0.0625%) and carvacrol (CAR; 0.
View Article and Find Full Text PDFSurface-browned but uncooked frozen breaded chicken products have been associated with salmonellosis outbreaks due to inadequate or no cooking of the products before consumption. This study was conducted to evaluate the effect of three antimicrobials against Salmonella during manufacture of a surface-browned, uncooked frozen breaded chicken meat product. Fresh chicken breast meat portions (5 by 5 by 5 cm) were inoculated (4 to 5 log CFU/g) with Salmonella and mixed with caprylic acid (CAA; 0.
View Article and Find Full Text PDFUnlabelled: Caprylic acid (CAA), carvacrol (CAR), ε-polylysine (POL), and their combinations were evaluated for reduction of Salmonella contamination in not-ready-to-eat surface-browned, frozen, breaded chicken products. Fresh chicken breast meat pieces (5 × 5 × 5 cm) were inoculated with Salmonella (7-strain mixture; 4-5 log CFU/g) and mixed with distilled water (control) or with CAA, CAR, and POL as single or combination treatments of 2 or 3 ingredients. Sodium chloride (1.
View Article and Find Full Text PDFThis study aimed to evaluate the effects of the level and sequence of hurdles, applied during growth, on the subsequent heat and acid tolerances of a 10-strain composite of Listeria monocytogenes. Individual strains were grown in glucose-free tryptic soy broth with 0.6% yeast extract (TSBYE-G).
View Article and Find Full Text PDFMicroorganisms persisting in slaughter plant environments may develop acid resistance and be translocated to other environmental surfaces or products. The objective of this study was to evaluate the potential of Escherichia coli O157:H7 to form biofilms and maintain acid resistance, under different culture habituation scenarios, on stainless steel coupons (2 x 5 x 0.08 cm), in the presence of beef carcass decontamination runoff fluids (washings).
View Article and Find Full Text PDFThe majority of published studies on the adaptive heat or acid tolerance response of Listeria monocytogenes have been performed with a single strain exposed to a single adaptation treatment; however, in food ecosystems, microorganisms commonly exist as multi-species communities and encounter multiple stresses, which may result in "stress hardening". Therefore, the present study evaluated the adaptive responses to heat (52, 57 and 63 degrees C) or lactic acid (pH 3.5) of a 10-strain composite of L.
View Article and Find Full Text PDFThe effect of aerobic and anaerobic conditions on growth initiation by a 10-strain composite of Listeria monocytogenes (10(4) CFU/ml) was evaluated in tryptic soy broth with 0.6% yeast extract (TSBYE) as a function of 220 combinations of pH (3.82 to 7.
View Article and Find Full Text PDFThis study assessed the acid tolerance response (ATR) of stationary phase, acid-adapted (tryptic soy broth [TSB]+1% glucose) or nonacid-adapted (glucose-free TSB) Escherichia coli O157:H7 strains (ATCC43889, ATCC43895, ATCC51658 and EO139), grown individually or in a mixed culture, prior to inoculation of beef or meat decontamination runoff (washings) fluids (acidic [pH 4.95] or nonacidic [pH 7.01]).
View Article and Find Full Text PDFTwenty-five Listeria monocytogenes strains of various serotypes and sources, including clinical and food isolates associated with the same outbreaks, were characterized and compared based on growth rates and heat and acid death rates. Growth was monitored in tryptic soy broth supplemented with 0.6% yeast extract (TSBYE) at 4 and 30 degrees C for 32 days and 20 h, respectively.
View Article and Find Full Text PDFThis study evaluated the behavior of Escherichia coli O157:H7 during aerobic storage, after storage in vacuum packages, on beef inoculated with cultures prepared (35 degrees C, 24 h) in tryptic soy broth without dextrose (TSB), nonacid hot water carcass decontamination runoff fluids (washings; pH 6.0; WASH), cells from biofilms formed on stainless steel coupons in WASH (WETB), or WETB dried (25 degrees C, 12 h) before harvesting of cells (DRYB). These inocula were applied to fresh beef pieces (40 cm2), which were then left untreated or treated by immersion in hot water (75 degrees C) followed by 2% lactic acid (55 degrees C; hot water/lactic acid [HW/LA]), for 30 s each.
View Article and Find Full Text PDFThis study evaluated the impact of inoculum preparation and storage conditions on the response of Escherichia coli O157:H7 exposed to consumer-induced stresses simulating undercooking and digestion. Lean beef tissue samples were inoculated with E. coli O157:H7 cultures prepared in tryptic soy broth or meat decontamination runoff fluids (WASH) or detached from moist biofilms or dried biofilms formed on stainless steel coupons immersed in inoculated WASH.
View Article and Find Full Text PDFThe objective of this study was to evaluate the influence of predrying treatments, i.e., peeling, blanching prior to inoculation, and dipping in organic acid solutions, on inactivation of Salmonella during drying (60 degrees C for 14 h) and aerobic storage (25 degrees C for 28 days) of inoculated (five-strain composite, 7.
View Article and Find Full Text PDFThis study evaluated survival/growth of acid-adapted or nonadapted Escherichia coli O157:H7 inoculated (4 log CFU/wound) in wounds (10 mm deepx6 mm diameter) of apples. Wounds were inoculated with a green fluorescent protein (GFP)-expressing derivative of a rifampicin-resistant strain of E. coli O157:H7 ATCC 43895 and allowed to attach (1 h).
View Article and Find Full Text PDFThis study evaluated resistance to sanitizing solutions of Escherichia coli O157:H7 cells forming biofilms on stainless steel coupons exposed to inoculated meat decontamination runoff fluids (washings). A previously acid-adapted culture of a rifampicin-resistant derivative of E. coli O157:H7 strain ATCC 43895 was inoculated in unsterilized or sterilized combined hot-water (85 degrees C) and cold-water (10 degrees C) (50/50 [vol/vol]) composite water (W) washings (pH 6.
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