Survival of Escherichia coli O157:H7 during the Manufacture of Pepperoni

Riordan, D. C. R.; Duffy, Geraldine; Sheridan, J.J.; Eblen, Brian S.; Whiting, Richard C.; Blair, I.S.; McDowell, David A.

doi:10.4315/0362-028x-61.2.146

Cited by 68 publications

(23 citation statements)

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“…In many of the studies included in this meta-analysis, it was observed that lower levels of pH (4-7, 11, 14, 49) and a w (49,57) are associated with greater reductions in E. coli in fermented meats. However, from our analyses of the collated data, while inactivation of E. coli ensues when environmental factors preclude growth, further decreases in pH or a w do not appear to greatly hasten inactivation.…”

Section: Discussionmentioning

confidence: 99%

Quantification of the Relative Effects of Temperature, pH, and Water Activity on Inactivation of Escherichia coli in Fermented Meat by Meta-Analysis

McQuestin

Shadbolt

Ross

2009

Appl Environ Microbiol

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Outbreaks of Escherichia coli infections linked to fermented meats have prompted much research into the kinetics of E. coli inactivation during fermented meat manufacture. A meta-analysis of data from 44 independent studies was undertaken that allowed the relative influences of pH, water activity (a w ), and temperature on E. coli survival during fermented meat processing to be investigated. Data were reevaluated to determine rates of inactivation, providing 484 rate data points with various pH (2.8 to 6.14), a w (0.75 to 0.986), and temperature (؊20 to 66°C) values, product formulations, and E. coli strains and serotypes. When the data were presented as an Arrhenius model, temperature (0 to 47°C) accounted for 61% of the variance in the ln(inactivation rate) data. In contrast, the pH or a w measured accounted for less than 8% of variability in the data, and the effects of other pH-and a w -based variables (i.e., total decrease and rates of reduction of those factors) were largely dependent on the temperature of the process. These findings indicate that although temperatures typically used in fermented meat manufacture are not lethal to E. coli per se, when other factors prevent E. coli growth (e.g., low pH and a w ), the rate of inactivation of E. coli is dominated by temperature. In contrast, inactivation rates at temperatures above ϳ50°C were characterized by smaller z values than those at 0 to 47°C, suggesting that the mechanisms of inactivation are different in these temperature ranges. The Arrhenius model developed can be used to improve product safety by quantifying the effects of changes in temperature and/or time on E. coli inactivation during fermented meat manufacture.Fermented meats encompass a diverse range of product styles in which raw, ground meat is preserved by the processes of fermentation and drying (or maturation). These products are typically manufactured without a bactericidal heat treatment, and instead, inhibition of growth and inactivation of contaminating pathogens rely upon the collective effects of acid pH, reduced water activity (a w ), and the presence of lactic acid and, potentially, curing salts (nitrate and/or nitrite) and spices. However, pathogenic Escherichia coli can contaminate and survive in fermented meat products at levels sufficient to cause serious illness in consumers, as evidenced by numerous outbreaks of E. coli infections epidemiologically linked to uncooked fermented meat products (8,9,54,64). Knowledge of the kinetics of nonthermal inactivation of E. coli, and the factors affecting it, is important to be able to optimize the safety of fermented meat processes.Several research groups have conducted studies on the survival of pathogenic E. coli during the processing of specific fermented meat products (4,6,14,16,23,25). In some cases, the effects of alternative ingredients or processing parameters have also been determined (12,21,24,30). Such investigations have allowed the lethality of a specific fermented meat process to be determined and the microbiological safe...

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Section: Discussionmentioning

confidence: 99%

Quantification of the Relative Effects of Temperature, pH, and Water Activity on Inactivation of Escherichia coli in Fermented Meat by Meta-Analysis

McQuestin

Shadbolt

Ross

2009

Appl Environ Microbiol

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“…Studies on the survival of E. coli O157:H7 cells in dried and fermented meat products (Hinkens et al, 1996;Faith, Parniere, Larson, Lorang, & Luchansky, 1997, 1998bFaith et al, 1998c;Riordan et al, 1998) have indicated that traditional fermentation processes, which do not include a thermal processing step, have not achieved a 5-log reduction of inoculated E. coli O157:H7 cells. Contaminated dried meats, such as jerky, may pose a potentially greater threat to consumers than fermented meats since jerky can easily be prepared at home with limited equipment and precision in methods used (Faith et al, 1998a).…”

Section: Introductionmentioning

confidence: 99%

Pretreatment effect on inactivation of Escherichia coli O157:H7 inoculated beef jerky

Albright

Kendall

Avens

et al. 2003

LWT - Food Science and Technology

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Changes in inoculated Escherichia coli O157:H7 populations were determined during drying (62.5 C, 10 h) of whole muscle beef jerky slices pretreated by: (1) immersing in boiling water (94 C, 15 s), then marinating (4 C, 24 h); (2) seasoning (4 C, 24 h), then immersing in a pickling brine (78 C, 90 s); (3) immersing in a vinegar/water (750/750 mL) solution (57.5 C, 20 s), then marinating (4 C, 24 h); and (4) marinating (4 C, 24 h), then immersing in a vinegar/water (750/750 mL) solution (57.5 C, 20 s). Samples were analysed (bacterial enumeration with selective and nonselective agar media, pH, and a w ) following inoculation, each preparation step, and at 0, 4, 6, 8 and 10 h of drying. While all pre-drying treatments resulted in significant ðPo0:05Þ bacterial reductions, treatment 2 resulted in the greatest pre-drying reduction (3.1-4.1 log cfu/cm 2 ) and the highest overall reduction at 10 h drying (5.7-5.8 log cfu/cm 2 ). Total reductions for treatments 1, 3 and 4 after 10 h drying were 4.3-4.5, 4.9-5.2 and 4.7-4.8 log cfu/cm 2 , respectively. Bacterial populations declined to o1.0 log cfu/cm 2 after 30 d storage and remained at this level throughout 90 d storage. These results should be useful in developing guidelines for jerky preparation by consumers and processors.

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“…With the exception of products with several months long ripening periods, such inactivation ratio cannot be expected under typical, currently practiced fermentation and drying conditions and additional hurdles are required. It is known that traditional processes for manufacturing pepperoni served to provide only 2-log reduction in E. coli O157:H7 (Faith, Parniere, Larson, Lorang, & Luchansky, 1997;Riordan et al, 1998). Normanno et al (2002) found that E. coli O157:H7 declined four log cycles in some inoculated short ripened Italian fermented sausage.…”

Section: Introductionmentioning

confidence: 97%