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Siyun Wang - One of the best experts on this subject based on the ideXlab platform.

  • heat resistance of salmonella enterica is increased by pre adaptation to Peanut Oil or sub lethal heat exposure
    2016
    Co-Authors: Karen Fong, Siyun Wang
    Abstract:

    Cross-protection represents a considerable challenge in the food industry where hurdled interventions are often employed to reduce Salmonella contamination. The heat resistance of Salmonella strains from five serotypes (i.e., Typhimurium, Enteritidis, Tennessee, Thompson and Hartford) at 70 °C was determined by measurement of viable cell populations before and after adaptation to two common stresses employed in low-water activity food processing, desiccation and sub-lethal heat treatment. Survival of Salmonella at 70 °C significantly increased (p < 0.05) following the six-day incubation in Peanut Oil (aw 0.52 ± 0.00) and/or the exposure to a sub-lethal heat treatment at 45 °C for 3 min. Quantitative PCR revealed upregulation of two desiccation stress-related genes, fadA and otsB, following the Peanut Oil incubation, whereas heat treatment induced upregulation of a heat-resistance gene, dnaK. Invasion gene invA and alternative sigma factor rpoE were downregulated following either of the treatments. Interestingly, different Salmonella strains yielded different transcriptional profiles. The strain-specific resistance phenotypes and transcriptional profiles provided further insights into the mechanisms employed to tolerate desiccation and heat stresses in the food industry.

  • strain specific survival of salmonella enterica in Peanut Oil Peanut shell and chia seeds
    2016
    Co-Authors: Karen Fong, Siyun Wang
    Abstract:

    In North America, outbreaks of Salmonella have been linked to low-water activity (aw) foods, such as nuts and seeds. These outbreaks have implicated an assortment of Salmonella serotypes. Some Salmonella serotypes (e.g., Enteritidis and Typhimurium) cause high proportions of salmonellosis. Nevertheless, there has recently been an emergence of uncommon Salmonella serotypes and strains (e.g., Tennessee, Hartford, and Thompson) in low-aw foods. The aim of this study was to evaluate the survival characteristics of Salmonella serotypes Enteritidis, Typhimurium, Tennessee, Hartford, and Thompson in three low-aw food ingredients with varying aw: Peanut Oil (aw = 0.521 ± 0.003), Peanut shell (aw = 0.321 ± 0.20), and chia seeds (aw = 0.585 ± 0.003). The survival of individual Salmonella strains on each food matrix was monitored for a maximum of 150 days by spreading the bacterial cells onto Luria-Bertani and/or xylose lysine deoxycholate agar. Overall, Salmonella survived for the longest periods of time in Peanut Oil (96 ± 8 days), followed by chia seeds (94 ± 46 days). The survival period was substantially reduced on the surface of Peanut shell (42 ± 49 h), although PCR after 70 days of incubation revealed the presence of Salmonella cells. In addition, Salmonella exhibited a strain-specific response in the three low-aw foods tested. Salmonella Hartford was identified as highly persistent in all low-aw food matrices, whereas Salmonella Typhimurium was the least persistent. The current research emphasizes the adaptable nature of Salmonella to low-aw food ingredients. This may pose additional problems owing to the downstream production of various end products. Additionally, unique survival characteristics among Salmonella strains highlight the need for tailored mitigation strategies regarding high-risk Salmonella strains in the food industry.

  • strain specific survival of salmonella enterica in Peanut Oil Peanut shell and chia seeds
    2016
    Co-Authors: Karen Fong, Siyun Wang
    Abstract:

    ABSTRACT In North America, outbreaks of Salmonella have been linked to low–water activity (aw) foods, such as nuts and seeds. These outbreaks have implicated an assortment of Salmonella serotypes. Some Salmonella serotypes (e.g., Enteritidis and Typhimurium) cause high proportions of salmonellosis. Nevertheless, there has recently been an emergence of uncommon Salmonella serotypes and strains (e.g., Tennessee, Hartford, and Thompson) in low-aw foods. The aim of this study was to evaluate the survival characteristics of Salmonella serotypes Enteritidis, Typhimurium, Tennessee, Hartford, and Thompson in three low-aw food ingredients with varying aw: Peanut Oil (aw = 0.521 ± 0.003), Peanut shell (aw = 0.321 ± 0.20), and chia seeds (aw = 0.585 ± 0.003). The survival of individual Salmonella strains on each food matrix was monitored for a maximum of 150 days by spreading the bacterial cells onto Luria-Bertani and/or xylose lysine deoxycholate agar. Overall, Salmonella survived for the longest periods of time i...

Antonio J A Meirelles - One of the best experts on this subject based on the ideXlab platform.

  • extraction of free fatty acids from Peanut Oil and avocado seed Oil liquid liquid equilibrium data at 298 2 k
    2008
    Co-Authors: Christianne Elisabete Da Costa Rodrigues, Antonio J A Meirelles
    Abstract:

    The present paper reports phase equilibrium experimental data for two systems composed by Peanut Oil or avocado seed Oil + commercial oleic acid + ethanol + water at 298.2 K and different water contents in the solvent. The addition of water to the solvent reduces the loss of neutral Oil in the alcoholic phase and improves the solvent selectivity. The experimental data were correlated by the NRTL and UNIQUAC models. The global deviations between calculated and experimental values were 0.63 % and 1.08 %, respectively, for the systems containing avocado seed Oil. In the case of systems containing Peanut Oil those deviations were 0.65 % and 0.98 %, respectively. Such results indicate that both models were able to reproduce correctly the experimental data, although the NRTL model presented a better performance.

Karen Fong - One of the best experts on this subject based on the ideXlab platform.

  • heat resistance of salmonella enterica is increased by pre adaptation to Peanut Oil or sub lethal heat exposure
    2016
    Co-Authors: Karen Fong, Siyun Wang
    Abstract:

    Cross-protection represents a considerable challenge in the food industry where hurdled interventions are often employed to reduce Salmonella contamination. The heat resistance of Salmonella strains from five serotypes (i.e., Typhimurium, Enteritidis, Tennessee, Thompson and Hartford) at 70 °C was determined by measurement of viable cell populations before and after adaptation to two common stresses employed in low-water activity food processing, desiccation and sub-lethal heat treatment. Survival of Salmonella at 70 °C significantly increased (p < 0.05) following the six-day incubation in Peanut Oil (aw 0.52 ± 0.00) and/or the exposure to a sub-lethal heat treatment at 45 °C for 3 min. Quantitative PCR revealed upregulation of two desiccation stress-related genes, fadA and otsB, following the Peanut Oil incubation, whereas heat treatment induced upregulation of a heat-resistance gene, dnaK. Invasion gene invA and alternative sigma factor rpoE were downregulated following either of the treatments. Interestingly, different Salmonella strains yielded different transcriptional profiles. The strain-specific resistance phenotypes and transcriptional profiles provided further insights into the mechanisms employed to tolerate desiccation and heat stresses in the food industry.

  • strain specific survival of salmonella enterica in Peanut Oil Peanut shell and chia seeds
    2016
    Co-Authors: Karen Fong, Siyun Wang
    Abstract:

    In North America, outbreaks of Salmonella have been linked to low-water activity (aw) foods, such as nuts and seeds. These outbreaks have implicated an assortment of Salmonella serotypes. Some Salmonella serotypes (e.g., Enteritidis and Typhimurium) cause high proportions of salmonellosis. Nevertheless, there has recently been an emergence of uncommon Salmonella serotypes and strains (e.g., Tennessee, Hartford, and Thompson) in low-aw foods. The aim of this study was to evaluate the survival characteristics of Salmonella serotypes Enteritidis, Typhimurium, Tennessee, Hartford, and Thompson in three low-aw food ingredients with varying aw: Peanut Oil (aw = 0.521 ± 0.003), Peanut shell (aw = 0.321 ± 0.20), and chia seeds (aw = 0.585 ± 0.003). The survival of individual Salmonella strains on each food matrix was monitored for a maximum of 150 days by spreading the bacterial cells onto Luria-Bertani and/or xylose lysine deoxycholate agar. Overall, Salmonella survived for the longest periods of time in Peanut Oil (96 ± 8 days), followed by chia seeds (94 ± 46 days). The survival period was substantially reduced on the surface of Peanut shell (42 ± 49 h), although PCR after 70 days of incubation revealed the presence of Salmonella cells. In addition, Salmonella exhibited a strain-specific response in the three low-aw foods tested. Salmonella Hartford was identified as highly persistent in all low-aw food matrices, whereas Salmonella Typhimurium was the least persistent. The current research emphasizes the adaptable nature of Salmonella to low-aw food ingredients. This may pose additional problems owing to the downstream production of various end products. Additionally, unique survival characteristics among Salmonella strains highlight the need for tailored mitigation strategies regarding high-risk Salmonella strains in the food industry.

  • strain specific survival of salmonella enterica in Peanut Oil Peanut shell and chia seeds
    2016
    Co-Authors: Karen Fong, Siyun Wang
    Abstract:

    ABSTRACT In North America, outbreaks of Salmonella have been linked to low–water activity (aw) foods, such as nuts and seeds. These outbreaks have implicated an assortment of Salmonella serotypes. Some Salmonella serotypes (e.g., Enteritidis and Typhimurium) cause high proportions of salmonellosis. Nevertheless, there has recently been an emergence of uncommon Salmonella serotypes and strains (e.g., Tennessee, Hartford, and Thompson) in low-aw foods. The aim of this study was to evaluate the survival characteristics of Salmonella serotypes Enteritidis, Typhimurium, Tennessee, Hartford, and Thompson in three low-aw food ingredients with varying aw: Peanut Oil (aw = 0.521 ± 0.003), Peanut shell (aw = 0.321 ± 0.20), and chia seeds (aw = 0.585 ± 0.003). The survival of individual Salmonella strains on each food matrix was monitored for a maximum of 150 days by spreading the bacterial cells onto Luria-Bertani and/or xylose lysine deoxycholate agar. Overall, Salmonella survived for the longest periods of time i...

Christianne Elisabete Da Costa Rodrigues - One of the best experts on this subject based on the ideXlab platform.

  • extraction of free fatty acids from Peanut Oil and avocado seed Oil liquid liquid equilibrium data at 298 2 k
    2008
    Co-Authors: Christianne Elisabete Da Costa Rodrigues, Antonio J A Meirelles
    Abstract:

    The present paper reports phase equilibrium experimental data for two systems composed by Peanut Oil or avocado seed Oil + commercial oleic acid + ethanol + water at 298.2 K and different water contents in the solvent. The addition of water to the solvent reduces the loss of neutral Oil in the alcoholic phase and improves the solvent selectivity. The experimental data were correlated by the NRTL and UNIQUAC models. The global deviations between calculated and experimental values were 0.63 % and 1.08 %, respectively, for the systems containing avocado seed Oil. In the case of systems containing Peanut Oil those deviations were 0.65 % and 0.98 %, respectively. Such results indicate that both models were able to reproduce correctly the experimental data, although the NRTL model presented a better performance.

Kishor M. Wasan - One of the best experts on this subject based on the ideXlab platform.

  • the influence of lipids on stereoselective pharmacokinetics of halofantrine important implications in food effect studies involving drugs that bind to lipoproteins
    2002
    Co-Authors: Dion R. Brocks, Kishor M. Wasan
    Abstract:

    The objective of this study was to determine the effect of lipids on the pharmacokinetics of halofantrine enantiomers. Rats were given (+/-)-halofantrine HCl 2 mg/kg i.v., or 7 mg/kg orally. Some rats were rendered hyperlipidemic by intraperitoneal administration of poloxamer 407 1 g/kg, followed by (+/-)-halofantrine HCl intravenously. In other normolipidemic rats, (+/-)-halofantrine was administered under fasted conditions, or after Peanut Oil given orally. Halofantrine enantiomer plasma concentrations were considerably (>10-fold) increased in hyperlipidemia. Decreases were noted in the clearance, volume of distribution and the unbound fraction in plasma of the hyperlipidemic rats. Peanut Oil caused a significant 28% reduction in clearance of the (-), but not the (+) enantiomer (mean clearance reduced 11%) of halofantrine. After oral halofantrine, Peanut Oil resulted in a two- to threefold increase in the plasma area under the curves of halofantrine enantiomers. Halofantrine enantiomer pharmacokinetics are highly dependent upon plasma lipid concentrations. Oral lipids may result in a stereoselective interaction at the level of clearance. Because lipids may affect clearance of drugs that bind to lipoproteins, in determining bioavailability of such drugs in food-effect studies, reference intravenous groups should be included to separate true increase in bioavailability from the effects of decreased clearance.

  • the influence of lipids on stereoselective pharmacokinetics of halofantrine important implications in food effect studies involving drugs that bind to lipoproteins
    2002
    Co-Authors: Dion R. Brocks, Kishor M. Wasan
    Abstract:

    Abstract The objective of this study was to determine the effect of lipids on the pharmacokinetics of halofantrine enantiomers. Rats were given (±)‐halofantrine HCl 2 mg/kg i.v., or 7 mg/kg orally. Some rats were rendered hyperlipidemic by intraperitoneal administration of poloxamer 407 1 g/kg, followed by (±)‐halofantrine HCl intravenously. In other normolipidemic rats, (±)‐halofantrine was administered under fasted conditions, or after Peanut Oil given orally. Halofantrine enantiomer plasma concentrations were considerably (>10‐fold) increased in hyperlipidemia. Decreases were noted in the clearance, volume of distribution and the unbound fraction in plasma of the hyperlipidemic rats. Peanut Oil caused a significant 28% reduction in clearance of the (−), but not the (+) enantiomer (mean clearance reduced 11%) of halofantrine. After oral halofantrine, Peanut Oil resulted in a two‐ to threefold increase in the plasma area under the curves of halofantrine enantiomers. Halofantrine enantiomer pharmacokinetics are highly dependent upon plasma lipid concentrations. Oral lipids may result in a stereoselective interaction at the level of clearance. Because lipids may affect clearance of drugs that bind to lipoproteins, in determining bioavailability of such drugs in food‐effect studies, reference intravenous groups should be included to separate true increase in bioavailability from the effects of decreased clearance. © 2002 Wiley‐Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:1817–1826, 2002