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V M Balasubramaniam - One of the best experts on this subject based on the ideXlab platform.
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Lethality enhancement of pressure-assisted thermal processing against Bacillus amyloliquefaciens spores in Low-Acid media using antimicrobial compounds
Food Control, 2016Co-Authors: Hossein Daryaei, V M Balasubramaniam, Ahmed E. Yousef, J. David Legan, Abdullatif TayAbstract:Abstract Pressure-assisted thermal processing (PATP; 500–700 MPa, 90–121 °C) offers new opportunities to sterilize Low-Acid Foods while preserving quality attributes to an extent greater than is possible with traditional thermal processing (TP). This study was conducted to evaluate the possibility of enhancing PATP lethality against the spores of Bacillus amyloliquefaciens , by sensitizing the spores with selected antimicrobial compounds (including emphasis on the use of natural antimicrobials) prior to treatment. A spore crop of B. amyloliquefaciens TMW 2.479 Fad 82, that had previously shown high resistance to combined pressure-heat treatment, was prepared on Nutrient Agar medium supplemented with 10 mg L −1 MnSO 4 ·H 2 O and incubated at 32 °C for 3 d. Spores were inoculated (at ∼10 7 –10 8 CFU mL −1 inoculum level) in HEPES buffer (pH ≤ 7.0) or selected Low-Acid Foods (pH 5.2–5.6) with or without added antimicrobial compounds. The samples were then treated at 600 MPa and 105 °C (PATP) or 0.1 MPa and 105 °C (TP) for various holding times. Among different compounds tested, Low-molecular-weight chitosan, and combination of chitosan with some surfactants were most effective ( P
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inactivation of geobacillus stearothermophilus spores in Low Acid Foods by pressure assisted thermal processing
Journal of the Science of Food and Agriculture, 2015Co-Authors: Juhee Ahn, Hyeon-yong Lee, V M BalasubramaniamAbstract:BACKGROUND The effect of pressure-assisted thermal processing (PATP) on the inactivation of Geobacillus stearothermophilus spores was determined in deionized water, cooked ground beef, egg patty mince, whole milk and mashed potatoes at 105 °C under 500 and 700 MPa. RESULTS The numbers of G. stearothermophilus spores in deionized water and milk were reduced by more than 6 log CFU mL−1 at 700 MPa and 105 °C, whereas those in cooked beef were reduced by 4.27 log CFU g−1. The inactivation patterns of G. stearothermophilus spores in all food matrices folLowed nonlinear behavior, showing that Weibull model fitted well to the inactivation curves of G. stearothermophilus spores in Low-Acid Foods. CONCLUSION The complex food matrices caused a protective effect on the inactivation of G. stearothermophilus spores during PATP. The results provide useful information in inactivation kinetics of bacterial spores for validating PATP-processed Low-Acid Foods. © 2014 Society of Chemical Industry
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Inactivation of Geobacillus stearothermophilus spores in Low‐Acid Foods by pressure‐assisted thermal processing
Journal of the Science of Food and Agriculture, 2014Co-Authors: Juhee Ahn, Hyeon-yong Lee, V M BalasubramaniamAbstract:BACKGROUND The effect of pressure-assisted thermal processing (PATP) on the inactivation of Geobacillus stearothermophilus spores was determined in deionized water, cooked ground beef, egg patty mince, whole milk and mashed potatoes at 105 °C under 500 and 700 MPa. RESULTS The numbers of G. stearothermophilus spores in deionized water and milk were reduced by more than 6 log CFU mL−1 at 700 MPa and 105 °C, whereas those in cooked beef were reduced by 4.27 log CFU g−1. The inactivation patterns of G. stearothermophilus spores in all food matrices folLowed nonlinear behavior, showing that Weibull model fitted well to the inactivation curves of G. stearothermophilus spores in Low-Acid Foods. CONCLUSION The complex food matrices caused a protective effect on the inactivation of G. stearothermophilus spores during PATP. The results provide useful information in inactivation kinetics of bacterial spores for validating PATP-processed Low-Acid Foods. © 2014 Society of Chemical Industry
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Evaluation of the instrumental quality of pressure-assisted thermally processed carrots
Journal of Food Science, 2007Co-Authors: Loc Thai Nguyen, Navin K. Rastogi, V M BalasubramaniamAbstract:This study was conducted to compare the effectiveness of pressure-assisted thermal processing (PATP) in preserving the texture, color, and carotene content of carrot cylinders in the pressure range of 500 to 700 MPa and the temperature range of 95 to 121 degrees C. The effectiveness of PATP was compared with that of conventional thermal processing (TP) by matching carrot preprocess temperature history. Results indicated that under comparable process temperatures (up to 105 degrees C), PATP retained the carrot quality attributes such as color and carotene content better than TP. However, process and preprocess thermal history at 121 degrees C greatly influenced carrot textural change and pressure protective effects were less pronounced. This study demonstrated that PATP has the potential to produce Low-Acid Foods with a relatively better quality than TP.
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Monitoring biochemical changes in bacterial spore during thermal and pressure-assisted thermal processing using FT-IR spectroscopy.
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Anand Subramanian, V M Balasubramaniam, Juhee Ahn, Luis E. Rodriguez-saonaAbstract:Pressure-assisted thermal processing (PATP) is being widely investigated for processing Low Acid Foods. However, its microbial safety has not been well established and the mechanism of inactivation of pathogens and spores is not well understood. Fourier transform infrared (FT-IR) spectroscopy was used to study some of the biochemical changes in bacterial spores occurring during PATP and thermal processing (TP). Spore suspensions (∼109 CFU/mL of water) of Clostridium tyrobutyricum, Bacillus sphaericus, and three strains of Bacillus amyloliquefaciens were treated by PATP (121 °C and 700 MPa) for 0, 10, 20, and 30 s and TP (121 °C) for 0, 10, 20, and 30 s. Treated and untreated spore suspensions were analyzed using FT-IR in the mid-infrared region (4000–800 cm−1). Multivariate classification models based on soft independent modeling of class analogy (SIMCA) were developed using second derivative-transformed spectra. The spores could be differentiated up to the strain level due to differences in their biochem...
Hosahalli S. Ramaswamy - One of the best experts on this subject based on the ideXlab platform.
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Novel processing methods: updates on Acidified vegetables thermal processing
Current Opinion in Food Science, 2018Co-Authors: Yetenayet B. Tola, Hosahalli S. RamaswamyAbstract:Conventional thermal processing of Low Acid Foods experiences significant quality loses due to intense thermal processing schedules. Even though relative improvement in quality of canned Foods achieved through modification of processing and packaging methods, due to required high lethality, commercial thermal sterilization process are still heat and energy intensive. Combined use of product pH (pH
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Microbiological Design and Validation of Thermal and High Pressure Processing of Acidified Carrots and Assessment of Product Quality
Journal of Food Processing and Preservation, 2015Co-Authors: Yetenayet B. Tola, Hosahalli S. RamaswamyAbstract:Modification of pH and combined use of novel processing methods may be a good strategy to improve the quality of canned vegetables. In this study, selected thermal (TP) and high pressure-assisted thermal (HP-T) processing methods were validated for citric Acid-infused carrots (pH ≤ 4.5) using Bacillus licheniformis spores. Previously established thermal inactivation kinetics data were used to setup the target process times (to achieve 7-log kill of B. licheniformis). The microbial spores were inoculated at the center of simulated carrot alginate beads and subjected to different processing methods. Delivered process lethalities, evaluated by the microbial count/re-count method and measured time–temperature data, were equal to or higher than the targeted values. No survivors were found after the treatments, demonstrating the adequacy of the processes. Texture, color and β-carotene retention in processed carrots, evaluated and compared with those processed under conventional canning, showed higher texture retention (P 0.05) with respect to color change. In terms of β-carotene, carrots subjected to a relatively more severe heat treatment (water immersion mode in static retort) showed better β-carotene extractability than samples from HP-T. Practical Applications Conventional thermal processing of “Low Acid” Foods (pH > 4.6) experiences significant quality loss due to the long thermal processing times required to inactivate spores of the key pathogen Clostridium botulinum. Alternative thermal processing techniques have evolved to shorten the processing times by enhancing heating rate to the product through process modifications or using thin profile packages. Even though quality retention can be enhanced through these modifications, thermal damage to quality is still indispensable since the sensitively microbial destruction to heat remain unaltered. Product Acidification moves the “Low Acid” Foods to “Acid” category, thereby shifting the process regulation from the high temperature sterilization to the Lower temperature pasteurization conditions. Savings in energy and reduction in process time immediately become obvious. Novel Acidification methods are necessary for making the process efficient. Bacillus licheniformis is important and a suitable microorganism for validating thermal processing of Acidified Foods. The combined use of Acid infusion methods and alternative thermal processing technologies could play a significant role to improve quality of Acidified Foods as compared to current practices.
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combined effects of high pressure moderate heat and ph on the inactivation kinetics of bacillus licheniformis spores in carrot juice
Food Research International, 2014Co-Authors: Yetenayet B. Tola, Hosahalli S. RamaswamyAbstract:Abstract The objective of this research was to evaluate the combined effect of high pressure processing (temperature, pressure and time) and product (pH) related variables on destruction kinetics of spores of Bacillus licheniformis in carrot juice. A 3-level factorial experimental design was used with the microbial spores inoculated into carrot juice at the natural pH (6.2) and Acidified pH (4.5 and 5.5), pressure (400, 500 or 600 MPa), temperature (40, 50, and 60 °C) and time (0–40 min) conditions. D values found varied from 0.6 to 14.1 min based on the temperature, pressure and pH level combinations. The corresponding temperature and pressure dependency of D values were in the range 23.3 to 31 °C and 241 to 465 MPa, respectively. The destruction pattern was also dependent on pH, with Lower pH contributing to higher destruction rate. Conventional log-linear model and Weibull model were used to describe the survivor curves and for predicting processing time to achieve a 5 D spore reduction. The survivor curves exhibited slightly upward concavity and therefore better described by a Weibull than the log-linear model. Treatment combinations showed significant ( p ≤ 0.05) effects on D and z values of log-linear model and rate parameter (α) of Weibull model. The 5 D spore count reduction times estimated using Weibull model parameters were longer than those from the log-linear model, generally demonstrating an over-treatment. Overall, the pH reduction of Low Acid Foods showed a significant enhancement of rate of destruction of B. licheniformis spores.
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thermal destruction kinetics of bacillus licheniformis spores in carrot juice extract as influenced by ph type of Acidifying agent and heating method
Lwt - Food Science and Technology, 2014Co-Authors: Yetenayet B. Tola, Hosahalli S. RamaswamyAbstract:The combined effects of different heating methods (conventional (CH) vs. Ohmic (OH)), types of Acidifying agent (citric vs malic Acid) and pH levels (pH 4.5, 5.5 and 6.2) were investigated to study their influence on destruction kinetics of spores of Bacillus licheniformis. The ultimate aim to generate relevant kinetic data on an indicator microbial spore is useful for assessing the efficacy of thermal processes for Acid or Acidified Low Acid Foods. Kinetic parameters were evaluated according to the first-order kinetic model. Temperature and pH showed a highly significant (p 0.05) was observed with respect to D and z values between the two types of Acidifying agents.
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High Pressure Sterilization of Foods
Food Engineering Series, 2010Co-Authors: Hosahalli S. RamaswamyAbstract:High pressure processing for producing commercially sterile Low Acid Foods can either be treated as a pressure-assisted thermal sterilization (PATS) or a temperature-assisted pressure sterilization (TAPS) process. For a PATS process, achieving designated process lethality for commercial sterilization becomes the main issue. The selected process would rely on the effective use of compression heating of the food achieved during the pressurization process to bring the product to sterilizing temperatures and then adequately hold it under pressure to complete the sterilization process prior to releasing the pressure. In the second approach (TAPS), accelerated destruction caused by the pressure at the elevated temperatures is taken into account. Both TAPS and PATS could potentially give quality advantages to the HPP product. While the PATS process could more easily be cleared by regulatory agencies according to the guidelines used for traditional thermal processing, the TAPS process would require demonstration of accelerated spore destruction kinetics of pathogenic and spoilage bacterial spores.
Ahmed E. Yousef - One of the best experts on this subject based on the ideXlab platform.
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Mechanism of Bacillus subtilis spore inactivation induced by moderate electric fields
Innovative Food Science & Emerging Technologies, 2020Co-Authors: Lang-hong Wang, Ahmed E. Yousef, Taras Pyatkovskyy, Xin-an Zeng, Sudhir K SastryAbstract:ABSTRACT Bacterial endospores are the key safety targets for inactivation within Low-Acid Foods. Herein, we investigated the inactivation of Bacillus subtilis CGMCC 1.1087 spores (107 CFU/mL) in sterile distilled water using moderate electric fields (MEF, 300 V/cm) under various temperatures ( Industrial relevance Literature in the past few years has shown that moderate electric fields (MEF), typically associated with ohmic heating, have nonthermal effects on bacterial spores, leading to accelerated inactivation. The current work extends the range of temperatures to those well beLow thermally lethal conditions, and shows that some spore inactivation occurs under MEF, even when temperatures are sublethal. Little or no germination is observed, and spore inner membranes are increasingly compromised over time. The elucidation of such nonthermal effects would be significant to the food industry as it seeks increasingly nonthermal methods for inactivation of spores.
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Lethality enhancement of pressure-assisted thermal processing against Bacillus amyloliquefaciens spores in Low-Acid media using antimicrobial compounds
Food Control, 2016Co-Authors: Hossein Daryaei, V M Balasubramaniam, Ahmed E. Yousef, J. David Legan, Abdullatif TayAbstract:Abstract Pressure-assisted thermal processing (PATP; 500–700 MPa, 90–121 °C) offers new opportunities to sterilize Low-Acid Foods while preserving quality attributes to an extent greater than is possible with traditional thermal processing (TP). This study was conducted to evaluate the possibility of enhancing PATP lethality against the spores of Bacillus amyloliquefaciens , by sensitizing the spores with selected antimicrobial compounds (including emphasis on the use of natural antimicrobials) prior to treatment. A spore crop of B. amyloliquefaciens TMW 2.479 Fad 82, that had previously shown high resistance to combined pressure-heat treatment, was prepared on Nutrient Agar medium supplemented with 10 mg L −1 MnSO 4 ·H 2 O and incubated at 32 °C for 3 d. Spores were inoculated (at ∼10 7 –10 8 CFU mL −1 inoculum level) in HEPES buffer (pH ≤ 7.0) or selected Low-Acid Foods (pH 5.2–5.6) with or without added antimicrobial compounds. The samples were then treated at 600 MPa and 105 °C (PATP) or 0.1 MPa and 105 °C (TP) for various holding times. Among different compounds tested, Low-molecular-weight chitosan, and combination of chitosan with some surfactants were most effective ( P
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inactivation of bacillus stearothermophilus spores in egg patties by pressure assisted thermal processing
Lwt - Food Science and Technology, 2006Co-Authors: S. Rajan, Srilatha Pandrangi, V M Balasubramaniam, Ahmed E. YousefAbstract:Abstract The use of pressure-assisted thermal processing (PATP) to inactivate bacterial spores in shelf-stable Low-Acid Foods, without diminishing product quality, has received widespread industry interest. Egg patties were inoculated with Bacillus stearothermophilus spores (10 6 spores/g) and the product was packaged in sterile pouches by heat sealing. Test samples were preheated and then PATP-treated at 105 °C at various pressures and pressure-holding times. Thermal inactivation of spores was studied at 121 °C using custom-fabricated aluminum tubes; this treatment served as a control. Application of PATP at 700 MPa and 105 °C inactivated B. stearothermophilus spores, suspended in egg matrix rapidly, (4 log reductions in 5 min) when compared to thermal treatment at 121 °C (1.5 log reduction in 15 min). Spore inactivation by PATP progressed rapidly (3 log reductions at 700 MPa and 105 °C) during pressure-hold for up to 100 s, but greater holding times (up to 5 min) had comparatively limited effect. When PATP was applied to spores in water suspension or egg patties, D values were not significantly different. While thermal inactivation of spores folLowed first-order kinetics, PATP inactivation exhibited nonlinear inactivation kinetics. Among the nonlinear models tested, the Weibull model best described PATP inactivation of B. stearothermophilus spores in the egg product.
Seymour G. Gilbert - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous Heat Processing of High‐ and Low‐Acid Foods in Semirigid Containers—A Theoretical Analysis
Journal of Food Science, 1991Co-Authors: Kan-ichi Hayakawa, Jianjun Wang, Seymour G. GilbertAbstract:A one meal-set of military ration consists of heat sterilized, high- and Low-Acid Foods in semirigid containers. These Foods are processed separately because of large differences in lethality requirements. We examined the feasibility of simultaneously processing a meal-set consisting of chili con came, white rice, and sliced peach in syrup to minimize costs. Simultaneous processing was not possible by adjusting initial temperatures according to computer-simulation using food temperature data collected experimentally. However, it was possible when the container for peaches was insulated properly with expanded polystyrene. Proper insulation thickness was slightly dependent on z value of the target factor.
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simultaneous heat processing of high and Low Acid Foods in semirigid containers a theoretical analysis
Journal of Food Science, 1991Co-Authors: Kan-ichi Hayakawa, Jianjun Wang, Seymour G. GilbertAbstract:A one meal-set of military ration consists of heat sterilized, high- and Low-Acid Foods in semirigid containers. These Foods are processed separately because of large differences in lethality requirements. We examined the feasibility of simultaneously processing a meal-set consisting of chili con came, white rice, and sliced peach in syrup to minimize costs. Simultaneous processing was not possible by adjusting initial temperatures according to computer-simulation using food temperature data collected experimentally. However, it was possible when the container for peaches was insulated properly with expanded polystyrene. Proper insulation thickness was slightly dependent on z value of the target factor.
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Simultaneous Heat Processing of High- and Low-Acid Foods in Semirigid Containers—A Theoretical Analysis
Journal of Food Science, 1991Co-Authors: Kan-ichi Hayakawa, Jianjun Wang, Seymour G. GilbertAbstract:A one meal-set of military ration consists of heat sterilized, high- and Low-Acid Foods in semirigid containers. These Foods are processed separately because of large differences in lethality requirements. We examined the feasibility of simultaneously processing a meal-set consisting of chili con came, white rice, and sliced peach in syrup to minimize costs. Simultaneous processing was not possible by adjusting initial temperatures according to computer-simulation using food temperature data collected experimentally. However, it was possible when the container for peaches was insulated properly with expanded polystyrene. Proper insulation thickness was slightly dependent on z value of the target factor.
Mark L. Tamplin - One of the best experts on this subject based on the ideXlab platform.
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modelling the combined effects of salt sorbic Acid and nisin on the probability of growth of clostridium sporogenes in a controlled environment nutrient broth
Food Control, 2016Co-Authors: Elham Khanipour, Steve Flint, Owen J. Mccarthy, Matt Golding, Jon Palmer, D A Ratkowsky, T Ross, Mark L. TamplinAbstract:The safe preservation of new generation Foods (high moisture, Low salt, high pH and shelf stable under ambient conditions) is microbiologically challenging. The growth of Clostridium botulinum in Low Acid Foods is a hazard for consumers. In this study the combined effect of salt (sodium chloride) (0–4% w/v), potassium sorbate (0–4% w/v) and nisin (0–300 ppm) at two different pHs (5.5 and 7) on the probability of growth of Clostridium sporogenes spores, as a non-toxigenic surrogate of C. botulinum, was evaluated in nutrient broth. Nutrient broth was used as it can easily and accurately be adjusted and controlled in terms of composition, and alLows more rapid growth than is observed in food. The aims of this study were to develop probability of growth models in which the logit is expressed as a function of the concentrations of the selected preservatives. The developed models fit the data adequately. The c-values models were close to 1, indicating good predictive power. This indicates the performance of models would be satisfactory. The results of this study indicated that salt, potassium sorbate and nisin had significant inhibitory effects on the growth of C. sporogenes in high moisture (>95%) and high pH conditions (pH > 4.5). Combinations of the selected preservatives were more effective than any of them individually. The inhibitory effects of all three preservatives in the current study were pH dependent. Less stringent combinations of preservative concentrations were required experimentally to stop growth at pH 5.5 compared with pH 7.
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Evaluation of the effects of sodium chloride, potassium sorbate, nisin and lysozyme on the probability of growth of Clostridium sporogenes
International Journal of Food Science & Technology, 2013Co-Authors: Elham Khanipour, Steve Flint, Owen J. Mccarthy, Matt Golding, Jon Palmer, Mark L. TamplinAbstract:The safe preservation of new generation Foods (high moisture, Low Acidity and ambient shelf-stable Foods) is microbiologically challenging. The growth of Clostridium botulinum in Low Acid Foods is a hazard for consumers. The aim of this study was to evaluate the combined effect of salt (sodium chloride) (0-8 %w/v), sorbate (potassium sorbate) (0-4.5 %w/v), nisin (0-500 ppm) and lysozyme (0-500 ppm) on the survival of Cl. sporogenes as a non-toxigenic surrogate of Cl. botulinum in terms of the probability of growth by using a central composite rotatable design (CCRD). An additional aim was to observe how the combination of preservatives could reduce the level of required salt to inhibit the growth of Cl. sporogenes . The results indicated that salt and sorbate were the most effective factors in preventing the growth of Cl. sporogenes in high moisture (> 95%) and Low Acid conditions (pH 7). The probability of growth of Cl. sporogenes in broth was reduced by combinations of salt and sorbate. As expected, a combination of salt and sorbate was more effective than using either of them individually. Nisin and lysozyme had insignificant effects on the probability of growth of Cl. sporogenes ( p >0.05). Lysozyme individually and in combination with nisin had no inhibitory effect on Cl. sporogenes . In overall, the addition of sorbate and lysozyme may alLow the salt concentration to be reduced while preventing growth.
