Water Diffusion from a Bacterial Cell in Low‐Moisture Foods

Roopesh, M.S.; Tang, Juming; Qin, Zhong

doi:10.1111/1750-3841.13412

Cited by 31 publications

(7 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Due to the difference in water vapor pressure, the water molecules inside bacteria cells will diffuse through the cell membrane into the oil until a thermal dynamic equilibration is achieved. Therefore, it may take less than a second for the bacterial cells to desiccate inside the oil ( Syamaladevi et al., 2016b ), leading to enhanced thermal resistance. But further studies are needed to explicitly correlate water activity changes in oils with thermal resistance of bacterial cells in oil samples.…”

Section: Resultsmentioning

confidence: 99%

Understanding water activity change in oil with temperature

Yang

Guan

Sun

et al. 2020

Current Research in Food Science

Self Cite

View full text Add to dashboard Cite

Our recent studies and several publications suggest that the low water activity (a w ) of oil in thermal processing might be a major contributing factor towards the increased thermal resistance of bacteria in oils. In this study, we developed a reliable method to measure the water activity of oil by measuring the equilibrium relative humidity in a small headspace. Using this method, water activity of peanut oil was found to decrease exponentially with increasing temperature. A model derived from excess Gibbs free energy was fitted to the observations with an R 2 = 99.6% and RMSE = 0.01 (a w ). Our results suggest that the sharply reduced water activity of oil resulting from a rise in temperature could cause desiccation of bacteria. This is a possible explanation for the protective effect of oil in thermal processing.

show abstract

Section: Resultsmentioning

confidence: 99%

Understanding water activity change in oil with temperature

Yang

Guan

Sun

et al. 2020

Current Research in Food Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…The thin layers of bacterial cells on SiO 2 surfaces in the SEM images support our assumption that bacterial cells in SiO 2 are directly exposed to the ambient environment. Syamaladevi et al (31) estimated that it takes no more than a second for a bacterial cell to adjust its water content in response to humidity changes in the environment. Thus, bacterial cells were expected to be inactivated under isothermal and iso-a w,80°C conditions in TACs.…”

Section: Discussionmentioning

confidence: 99%

“…In the present study, a w,80°C refers to the equilibrium a w of the bacterial cells when exposed to a specific relative humidity at 80°C. Our recent study (31) suggests that, through moisture diffusion, the extremely small size of bacterial cells allows them to adjust the intracellular moisture content according to changes in environmental relative humidity within seconds. The a w,80°C was used for interpretation and data analysis because a w,80°C can be easily related to a w,25°C , which has been used to define low-moisture foods (32) and has been widely studied for its impact on thermal resistance of microorganisms in low-moisture environments.…”

Section: Discussionmentioning

confidence: 99%

Exponentially Increased Thermal Resistance of Salmonella spp. and Enterococcus faecium at Reduced Water Activity

Liu

Tang

Tadapaneni

et al. 2018

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

spp. exhibit prolonged survivability and high tolerance to heat in low-moisture foods. The reported thermal resistance parameters of spp. in low-moisture foods appear to be unpredictable due to various unknown factors. We report here that temperature-dependent water activity (a) plays an important role in the sharply increased thermal resistance of serovar Enteritidis PT 30 and its potential surrogate NRRL B-2354. In our study, silicon dioxide granules, as carriers, were separately inoculated with these two microorganisms and were heated at 80°C with controlled relative humidity between 18 and 72% (resulting in corresponding a values for bacteria between 0.18 and 0.72) in custom-designed test cells. The inactivation kinetics of both microorganisms fitted a log-linear model (, 0.83 to 0.97). Reductions in the a values of bacterial cells exponentially increased the (the time needed to achieve a 1-log reduction in a bacterial population at 80°C) values for Enteritidis and on silicon dioxide. The log-linear relationship between the values for each strain in silicon dioxide and its a values was also verified for organic wheat flour. showed consistently higher values than Enteritidis over the a range tested. The estimated z (the change in a needed to change by 1 log) values of Enteritidis and were 0.31 and 0.28, respectively. This study provides insight into the interpretation of thermal resistance that could guide the development and validation of thermal processing of low-moisture foods. In this paper, we established that the thermal resistance of the pathogen Enteritidis and its surrogate, as reflected by values at 80°C, increases sharply with decreasing relative humidity in the environment. The log-linear relationship between the values of each strain in silicon dioxide and its a values was also verified for organic wheat flour. The results provide new quantitative insight into the way in which the thermal resistance of microorganisms changes in low-moisture systems, and they should aid in the development of effective thermal treatment strategies for pathogen control in low-moisture foods.

show abstract

“…Dry food systems with low water activity are often susceptible to fungal contamination and their safety remains a challenge for processors (Syamaladevi, Tang, & Zhong, ). Despite a higher resistance observed in dry food systems, plasma treatment has been found to be considerably effective in reducing molds vis‐à‐vis other known methods.…”

Section: Plasma Led Fungal Inactivation In Foodsmentioning

confidence: 99%

Cold Plasma for Effective Fungal and Mycotoxin Control in Foods: Mechanisms, Inactivation Effects, and Applications

Misra

Yadav

Roopesh

et al. 2018

Comp Rev Food Sci Food Safe

256

169

View full text Add to dashboard Cite

Cold plasma treatment is a promising intervention in food processing to boost product safety and extend the shelf‐life. The activated chemical species of cold plasma can act rapidly against micro‐organisms at ambient temperatures without leaving any known chemical residues. This review presents an overview of the action of cold plasma against molds and mycotoxins, the underlying mechanisms, and applications for ensuring food safety and quality. The cold plasma species act on multiple sites of a fungal cell resulting in loss of function and structure, and ultimately cell death. Likewise, the species cause chemical breakdown of mycotoxins through various pathways resulting in degradation products that are known to be less toxic. We argue that the preliminary reports from cold plasma research point at good potential of plasma for shelf‐life extension and quality retention of foods. Some of the notable food sectors which could benefit from antimycotic and antimycotoxin efficacy of cold plasma include, the fresh produce, food grains, nuts, spices, herbs, dried meat and fish industries.

show abstract

Water Diffusion from a Bacterial Cell in Low‐Moisture Foods

Cited by 31 publications

References 22 publications

Understanding water activity change in oil with temperature

Understanding water activity change in oil with temperature

Exponentially Increased Thermal Resistance of Salmonella spp. and Enterococcus faecium at Reduced Water Activity

Cold Plasma for Effective Fungal and Mycotoxin Control in Foods: Mechanisms, Inactivation Effects, and Applications

Contact Info

Product

Resources

About