Heat Inactivation of Escherichia coli O157:H7 in Turkey Meat as Affected by Sodium Chloride, Sodium Lactate, Polyphosphate, and Fat Content

Kotrola, John S.; Conner, D. E.

doi:10.4315/0362-028x-60.8.898

Cited by 58 publications

(36 citation statements)

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“…Coconut cake was chosen since desiccated coconut has previously been associated with outbreaks of Salmonella (3,7). Peanut butter has a high fat content, which has been reported elsewhere to protect microorganisms against high temperature (33,42,54), although other reports are less conclusive (35,39).…”

Section: Pt4mentioning

confidence: 91%

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

Mattick

Jørgensen

Wang³

et al. 2001

Appl Environ Microbiol

135

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Salmonella spp. are reported to have an increased heat tolerance at low water activity (a w ; measured by relative vapor pressure [rvp]), achieved either by drying or by incorporating solutes. Much of the published data, however, cover only a narrow treatment range and have been analyzed by assuming first-order death kinetics. In this study, the death of Salmonella enterica serovar Typhimurium DT104 when exposed to 54 combinations of temperature (55 to 80°C) and a w (rvp 0.65 to 0.90, reduced using glucose-fructose) was investigated. The Weibull model (LogS ‫؍‬ ؊bt n ) was used to describe microbial inactivation, and surface response models were developed to predict death rates for serovar Typhimurium at all points within the design surface. The models were evaluated with data generated by using six different Salmonella strains in place of serovar Typhimurium DT104 strain 30, two different solutes in place of glucose-fructose to reduce a w , or six low-a w foods artificially contaminated with Salmonella in place of the sugar broths. The data demonstrate that, at temperatures of >70°C, Salmonella cells at low a w were more heat tolerant than those at a higher a w but below 65°C the reverse was true. The same patterns were generated when sucrose (rvp 0.80 compared with 0.90) or NaCl (0.75 compared with 0.90) was used to reduce a w , but the extent of the protection afforded varied with solute type. The predictions of thermal death rates in the low-a w foods were usually fail-safe, but the few exceptions highlight the importance of validating models with specific foods that may have additional factors affecting survival.

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Section: Pt4mentioning

confidence: 91%

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

Mattick

Jørgensen

Wang³

et al. 2001

Appl Environ Microbiol

135

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“…An increased fat content in food products increased the heat resistance of E. coli in some studies (Line et al, 1991; Huang et al, 1992; Ahmed et al, 1995; Smith et al, 2001; Liu et al, 2015), while other studies reported decreased resistance, no effect, or strain-specific effects (Kotrola and Conner, 1997; Vasan et al, 2014; Liu et al, 2015). The potential direct effects of fat on heat resistance of E. coli are confounded by the strong effect of fat on heat transfer in solid foods.…”

Section: Effects Of Salt or Sugar Addition In High Moisture Foodsmentioning

confidence: 97%

Some Like It Hot: Heat Resistance of Escherichia coli in Food

Gänzle

2016

Front. Microbiol.

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Heat treatment and cooking are common interventions for reducing the numbers of vegetative cells and eliminating pathogenic microorganisms in food. Current cooking method requires the internal temperature of beef patties to reach 71°C. However, some pathogenic Escherichia coli such as the beef isolate E. coli AW 1.7 are extremely heat resistant, questioning its inactivation by current heat interventions in beef processing. To optimize the conditions of heat treatment for effective decontaminations of pathogenic E. coli strains, sufficient estimations, and explanations are necessary on mechanisms of heat resistance of target strains. The heat resistance of E. coli depends on the variability of strains and properties of food formulations including salt and water activity. Heat induces alterations of E. coli cells including membrane, cytoplasm, ribosome and DNA, particularly on proteins including protein misfolding and aggregations. Resistant systems of E. coli act against these alterations, mainly through gene regulations of heat response including EvgA, heat shock proteins, σE and σS, to re-fold of misfolded proteins, and achieve antagonism to heat stress. Heat resistance can also be increased by expression of key proteins of membrane and stabilization of membrane fluidity. In addition to the contributions of the outer membrane porin NmpC and overcome of osmotic stress from compatible solutes, the new identified genomic island locus of heat resistant performs a critical role to these highly heat resistant strains. This review aims to provide an overview of current knowledge on heat resistance of E. coli, to better understand its related mechanisms and explore more effective applications of heat interventions in food industry.

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“…Stringer et al (39) noted, however, that although cells can be more heat resistant in fatty meat than in lean meat, the effect is not always observed. Similarly, Kotrola and Conner (22) found that heating cells of E. coli 0157:H7 in ground turkey of varying fat content did not affect survivability. Kotrola and Conner speculated that " fine grinding" of meat in their study may have so effectively dispersed fat within the lean phase that the protective effect of higher fat was obliterated.…”

Section: Resultsmentioning

confidence: 95%

Thermal Tolerance of O157 and non-O157 Shiga Toxigenic Strains of Escherichia coli, Salmonella, and Potential Pathogen Surrogates, in Frankfurter Batter and Ground Beef of Varying Fat Levels

Vasan

Geier

Ingham

et al. 2014

Journal of Food Protection

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The non-O157 Shiga toxigenic Escherichia coli (STEC) serogroups most commonly associated with illness are O26, O45, O103, O111, O121, and O145. We compared the thermal tolerance (D55°C) of three or more strains of each of these six non-O157 STEC serogroups with five strains of O157:H7 STEC in 7% fat ground beef. D55°C was also determined for at least one heat-tolerant STEC strain per serogroup in 15 and 27% fat ground beef. D55°C of single-pathogen cocktails of O157 and non-O157 STEC, Salmonella, and potential pathogen surrogates, Pediococcus acidilactici and Staphylococcus carnosus, was determined in 7, 15, and 27% fat ground beef and in frankfurter batter. Samples (25 g) were heated for up to 120 min at 55°C, survivors were enumerated, and log CFU per gram was plotted versus time. There were significant differences in D55°C across all STEC strains heated in 7% fat ground beef (P < 0.05), but no non-O157 STEC strain had D55°C greater than the range observed for O157 STEC. D55°C was significantly different for strains within serogroups O45, O145, and O157 (P < 0.05). D55°C for non-O157 STEC strains in 15 and 27% fat ground beef were less than or equal to the range of D55°C for O157. D55°C for pathogen cocktails was not significantly different when measured in 7, 15, and 27% fat ground beef (P ≥ 0.05). D55°C of Salmonella in frankfurter batter was significantly less than for O157 and non-O157 STEC (P < 0.05). Thermal tolerance of pathogen cocktails in ground beef (7, 15, or 27% fat) and frankfurter batter was significantly less than for potential pathogen surrogates (P < 0.05). Results suggest that thermal processes in beef validated against E. coli O157:H7 have adequate lethality against non-O157 STEC, that thermal processes that target Salmonella destruction may not be adequate against STEC in some situations, and that the use of pathogen surrogates P. acidilactici and S. carnosus to validate thermal processing interventions in ground beef and frankfurter batter would be of limited utility to processors.

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Heat Inactivation of Escherichia coli O157:H7 in Turkey Meat as Affected by Sodium Chloride, Sodium Lactate, Polyphosphate, and Fat Content

Cited by 58 publications

References 0 publications

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

Effect of Challenge Temperature and Solute Type on Heat Tolerance of Salmonella Serovars at Low Water Activity

Some Like It Hot: Heat Resistance of Escherichia coli in Food

Thermal Tolerance of O157 and non-O157 Shiga Toxigenic Strains of Escherichia coli, Salmonella, and Potential Pathogen Surrogates, in Frankfurter Batter and Ground Beef of Varying Fat Levels

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