Food component influence on water activity of low-moisture powders at elevated temperatures in connection with pathogen control

Jin, Yuqiao; Tang, Juming; Sablani, Shyam S.

doi:10.1016/j.lwt.2019.108257

Cited by 31 publications

(29 citation statements)

References 26 publications

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“…According to Kirby and Davies (31), heating of bacterial cells may result in loss of water increasing thermal resistance in a similar way to a medium with low water activity. Water activity represents the thermodynamic value depending on the type of food matrix and temperature similarly to water loss representing the amount of evaporation which is dependent on the food matrix and temperature (25,54). The measurement of water loss has been used in several studies to determine the water evaporation of samples during drying and it does provide useful data regarding the survival of bacterial pathogens including Salmonella when exposed to heat (9,33,70).…”

Section: Resultsmentioning

confidence: 99%

Survival of Salmonella on Red Meat in Response to Dry Heat

Sarjit¹,

Ravensdale²,

Coorey³

et al. 2021

Journal of Food Protection

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Red meat is associated with Salmonella outbreaks resulting in negative impacts for the processing industry. Little work has been reported on the use of dry heat as opposed to moist heat against Salmonella on red meat. We determined the effect of drying at 25°C and dry heat at 70°C with ~10% relative humidity (RH) for 1 h against eleven Salmonella strains of multiple serovars on beef, lamb, goat, and rubber as an inert surface. Each strain at ~108 cfu/ml was inoculated (100ul) onto ±1g (1cm2) of each surface and allowed to attach for 15 min in a microcentrifuge tube. Samples were then exposed to 70°C and 25°C with ~10% RH in a heating block. Surviving Salmonella numbers on surfaces were enumerated on a thin layer medium. If numbers were below the limit of detection (LOD), (2.01 log cfu/cm2), Salmonella cells were enriched before plating to determine the presence of viable cells. Water loss (%) from meat after at 25°C and 70°C was determined. Whole genomes of Salmonella were interrogated to identify the presence/absence of stress response genes (n=30) related to dry heat which may contribute to the survival of Salmonella. The survival of Salmonella at 25°C was significantly higher across all surfaces (~6.09–7.91 log cfu/cm2) as compared to 70°C (~3.66–6.33 log cfu/cm2). On rubber, numbers of Salmonella were <LOD at 70°C. Water loss at 70°C (~17.72–19.89%) was significantly higher as compared to 25°C (~2.98–4.11%). Salmonella was not detected on rubber while survival occurred on all red meat at 70°C, suggesting its protective effect against the effect of heat. All Salmonella strains carried 30 stress response genes which likely contributed to its survival. A multi-antibiotic resistant S. Typhimurium 2470 exhibited an increase in heat resistance at 70°C on beef and lamb as compared to other strains. Our work shows that dry heat at 70°C for 1 h against Salmonella on red meat is not a practical approach for effectively reducing or eliminating them from red meat.

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Section: Resultsmentioning

confidence: 99%

Survival of Salmonella on Red Meat in Response to Dry Heat

Sarjit¹,

Ravensdale²,

Coorey³

et al. 2021

Journal of Food Protection

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“…The average final a w in all cases was 0.44, the minimum measured reading was 0.33, and the maximum was 0.58. The final a w values indicate that there is no possibility of microbial growth in the dehydrated product obtained [44]. Figure 2 shows the change in the weather parameters during the test period with three sunny days.…”

Section: Resultsmentioning

confidence: 99%

Kinetics of Drying Medicinal Plants by Hybridization of Solar Technologies

Téllez¹,

Téllez²,

Navarro³

et al. 2020

Current Drying Processes

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Historically, medicinal plants have always had an important place in medicine. Medicinal plants processing represents a great challenge, due to their compounds sensitive to the environmental conditions that surround and degrade them. Mostly of these plants require to be dry to preserve its safety and medicinal properties; therefore, for proper drying, it is necessary to use sustainable devices that protect the desirable characteristics of plants from direct radiation. In this work, the kinetics of dehydration of three medicinal plants are presented in an indirect solar dryer. In addition, the experimental results were adjusted to nine mostly used models, to estimate the drying conditions required to achieve a desired final moisture content. Modified Page and Page were the models with better fit to experimental results. Furthermore, a computational simulation of temperature evolution and distribution inside the dryer is presented. These results agree with those obtained experimentally.

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“…This equation was initially developed to evaluate the impact of temperature on the a w of a pure system (Labuza & Altunakar, 2007), but has been used to model changes of a w in different dried food products or ingredients, including blueberry, pineapple, potato, and green algae, over a wide range of temperatures (Hossain et al., 2001; Lim et al., 1995; McMinn & Magee, 2003; Zuo et al., 2015). Recent studies show that by using the CCE, MSIs can be obtained for a larger range of temperatures and in less time than traditional methods (Jin et al., 2019; Tadapaneni et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

The influence of elevated temperatures and composition on the water activity of egg powders

Pérez-Reyes

Tang

Zhu

et al. 2021

J. Food Process. Preserv.

Self Cite

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This study aimed to investigate water activity (aw) changes in different egg powders (egg white, egg yolk, and whole egg) as influenced by temperature between 20°C and 80°C. A high‐temperature test cell was used to measure the aw in egg powders of different moisture contents (2 to 30% wet basis) during heating in a closed environment. Then, the net isosteric heat of sorption (qst) of the egg powders was calculated. The qst values were used in the Clausius–Clapeyron equation to generate the isotherms of the egg powders at 40°C and 80°C. The results showed that at fixed moisture content and temperature, egg yolk powder had higher aw than whole egg and egg white powders. In addition, aw of the three egg powders in closed containers all increased with temperature. Egg white powder had stronger binding capacity to water, as reflected by the higher qst, compared to the other two egg powders. Practical applications An important determinant for the survival of microorganisms during thermal treatments is food water activity (aw), which changes with temperature. Currently, there is no scientific data regarding aw changes in egg powders at elevated temperatures. Therefore, this study aimed to determine the aw changes in egg powders as a function of temperature and composition. Data produced by this study regarding aw changes provide useful information for designing effective heat treatments to control pathogens in egg powders. The isosteric data should also help estimate the energy efficiency of egg powder drying operations.

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Food component influence on water activity of low-moisture powders at elevated temperatures in connection with pathogen control

Cited by 31 publications

References 26 publications

Survival of Salmonella on Red Meat in Response to Dry Heat

Survival of Salmonella on Red Meat in Response to Dry Heat

Kinetics of Drying Medicinal Plants by Hybridization of Solar Technologies

The influence of elevated temperatures and composition on the water activity of egg powders

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