Effect of thermal treatments in oils on bacterial spore survival

Ababouch, L.; Busta, F. F.

doi:10.1111/j.1365-2672.1987.tb02681.x

Cited by 29 publications

(27 citation statements)

References 28 publications

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“…A number of studies have focused on the protective effect of lipid materials on microorganisms during heat treatments (Ababouch and Busta ; Ma and others ; Shigemoto and others ; Li and others ). Ma and others () observed unusually greater heat resistance of Salmonella strains in peanut butter with a w of 0.45 in comparison to many high‐moisture foods such as ground beef but with higher a w , attributed to the high fat content (approximately 53%) and low a w of peanut butter.…”

Section: Factors Influencing the Thermal Resistance Of Pathogens In Lmentioning

confidence: 99%

“…However, a greater fat content (56% compared with 47%) in peanut butter formulation did not influence the survival of the selected bacteria, so that >47% may offer no further protective effect of fat on the survivability of bacterial cells (Kataoka and others ). Ababouch and Busta () observed greater thermal resistance (higher D ‐ and z ‐values) of Bacillus cereus , Clostridium botulinum , and C. sporogenes spores suspended in oil (olive oil and commercial oil containing rapeseed oil and soy oil) compared to aqueous buffer (pH of 7.2). This was attributed to the reduction in a w during thermal treatments in the presence of lipid materials.…”

Section: Factors Influencing the Thermal Resistance Of Pathogens In Lmentioning

confidence: 99%

“…The spores survived better in olive oil compared to commercial oil, even though the water activity was slightly higher for olive oil, showing that oil composition may also directly contribute to the thermal resistance of microorganisms (Ababouch and Busta ). Furthermore, the significantly greater z ‐values of the spores presented in the oils compared to those in aqueous buffer, suggesting that, the inactivation mechanism of the spores in these matrices may be different (Ababouch and Busta ). Shigemoto and others () reported that Bacillus subtilis spores survived better at higher soybean oil content in an oil–water emulsion system.…”

Section: Factors Influencing the Thermal Resistance Of Pathogens In Lmentioning

confidence: 99%

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Influence of Water Activity on Thermal Resistance of Microorganisms in Low‐Moisture Foods: A Review

Roopesh

Tang

Villa-Rojas

et al. 2016

Comp Rev Food Sci Food Safe

270

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A number of recent outbreaks related to pathogens in low-moisture foods have created urgency for studies to understand the possible causes and identify potential treatments to improve low-moisture food safety. Thermal processing holds the potential to eliminate pathogens such as Salmonella in low-moisture foods. Water activity (a w ) has been recognized as one of the primary factors influencing the thermal resistance of pathogens in low-moisture foods. But most of the reported studies relate thermal resistance of pathogens to a w of low-moisture foods at room temperature. Water activity is a thermodynamic property that varies significantly with temperature and the direction of variation is dependent on the product component. Accurate methods to determine a w at elevated temperatures are needed in related research activities and industrial operations. Adequate design of commercial thermal treatments to control target pathogens in low-moisture products requires knowledge on how a w values change in different foods at elevated temperatures. This paper presents an overview of the factors influencing the thermal resistance of pathogens in low-moisture foods. This review focuses on understanding the influence of water activity and its variation at thermal processing temperature on thermal resistance of pathogens in different low-moisture matrices. It also discusses the research needs to relate thermal resistance of foodborne pathogens to a w value in those foods at elevated temperatures.

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Section: Factors Influencing the Thermal Resistance Of Pathogens In Lmentioning

confidence: 99%

Section: Factors Influencing the Thermal Resistance Of Pathogens In Lmentioning

confidence: 99%

Section: Factors Influencing the Thermal Resistance Of Pathogens In Lmentioning

confidence: 99%

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Influence of Water Activity on Thermal Resistance of Microorganisms in Low‐Moisture Foods: A Review

Roopesh

Tang

Villa-Rojas

et al. 2016

Comp Rev Food Sci Food Safe

270

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“…However, above the glass-transition temperature, T,, the free-volume (interpreted as the presence of a critical void volume required for the movement of a polymeric Ababouch and Busta, 1987; 0: C. botulinum Type A, Ababouch, 1987;0: B. subtilis, Sapru, 1991. segment) is considered to be the limiting factor for any reactions to take place (Crank and Park, 1968). It is therefore appropriate to describe the dependence of the reaction rate constant on the free-volume as:…”

Section: Methodsmentioning

confidence: 99%

Glassy State in Bacterial Spores Predicted by Polymer Glass‐Transition Theory

Sapru

Labuza

1993

Journal of Food Science

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Polymer glass-transition theory was used to gain information about a possible general mechanism to explain the high heat resistance of bacterial spores. In a glassy state the configuration of vital macromolecules and supramolecular assemblies in the spore protoplast would change extremely slowly when heated. The temperature dependence for heat inactivation rates above the glass-transition temperature was shown to be free-volume dependent and described by the kinetics commonly observed for glassy polymers. Glass-transition temperatures for various spores, predicted by nonlinear regression analysis of their heat inactivation rates at different temperatures, increased with increasing heat resistance as expected.

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“…The maximum thermostability of most microorganisms was found in the range of between 0.2 and 0.4 water activity (1,3,27,28,29). In typical ranges of water activities which are found in foodstuffs (a w Ͼ 0.8), the heat resistance of microorganisms generally increases at decreasing water activities.…”

mentioning

confidence: 93%

Effect of Water Activities of Heating and Recovery Media on Apparent Heat Resistance of Bacillus cereus Spores

Coroller¹,

Leguérinel²,

Mafart³

2001

Appl Environ Microbiol

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Spores of Bacillus cereus were heated and recovered in order to investigate the effect of water activity of media on the estimated heat resistance (i.e., the D value) of spores. The water activity (ranging from 0.9 to 1) of the heating medium was first successively controlled with three solutes (glycerol, glucose, and sucrose), while the water activity of the recovery medium was kept near 1. Reciprocally, the water activity of the heating medium was then kept at 1, while the water activity of the recovery medium was controlled from 0.9 to 1 with the same depressors. Lastly, in a third set of experiments, the heating medium and the recovery medium were adjusted to the same activity. As expected, added depressors caused an increase of the heat resistance of spores with a greater efficiency of sucrose with respect to glycerol and glucose. In contrast, when solutes were added to the recovery medium, under an optimal water activity close to 0.98, a decrease of water activity caused a decrease in the estimated D values. This effect was more pronounced when sucrose was used as a depressor instead of glycerol or glucose. When the heating and the recovery media were adjusted to the same water activity, a balancing effect was observed between the protective influence of the solutes during heat treatment and their negative effect during the recovery of injured cells, so that the overall effect of water activity was reduced, with an optimal value near 0.96. The difference between the efficiency of depressors was also less pronounced. It may then be concluded that the overall protective effect of a decrease in water activity is generally overestimated.It has been recognized that the heat resistance of bacterial spores depends on the medium in which the spores are heated. The maximum thermostability of most microorganisms was found in the range of between 0.2 and 0.4 water activity (1,3,27,28,29). In typical ranges of water activities which are found in foodstuffs (a w Ͼ 0.8), the heat resistance of microorganisms generally increases at decreasing water activities. However, the apparent effect of the water activity of the medium on spores or vegetative cells is complicated by the specific effect of solutes which are used as depressors. It is generally agreed that the occurrence of such solutes in the medium reduces the heat resistance of microorganisms. This antagonism between the protective effect of an increase in water activity and the opposite specific effect of depressors can explain conflicting data from various authors.The influence of salt on the thermostability of microorganisms is disputed and depends on the heated type of microorganism. Some authors found no effect of the sodium chloride concentration on the heat resistance of bacteria (9,29,32,42). Others observed a reduced heat resistance of microorganisms at increasing salt concentrations (7,12,22,23). On the contrary, a protective effect of salt was found in several studies (6,14,26,35,38,39,40). Corry (14) deduced from his data that sodium chloride had a therm...

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Effect of thermal treatments in oils on bacterial spore survival

Cited by 29 publications

References 28 publications

Influence of Water Activity on Thermal Resistance of Microorganisms in Low‐Moisture Foods: A Review

Influence of Water Activity on Thermal Resistance of Microorganisms in Low‐Moisture Foods: A Review

Glassy State in Bacterial Spores Predicted by Polymer Glass‐Transition Theory

Effect of Water Activities of Heating and Recovery Media on Apparent Heat Resistance of Bacillus cereus Spores

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