Microbiological Preservation of Cucumbers for Bulk Storage Using Acetic Acid and Food Preservatives

ABSTRACT: Microbial growth did not occur when cucumbers were preserved without a thermal process by storage in solutions containing acetic acid, sodium benzoate, and calcium chloride to maintain tissue firmness. The concentrations of acetic acid and sodium benzoate required to ensure preservation were low enough so that stored cucumbers could be converted to the finished product without the need to wash out and discard excess acid or preservative. Since no thermal process was required, this method of preservation would be applicable for storing cucumbers in bulk containers. Acid tolerant pathogens died off in less than 24 h with the pH, acetic acid, and sodium benzoate concentrations required to assure the microbial stability of cucumbers stored at 30 • C. Potassium sorbate as a preservative in this application was not effective. Yeast growth was observed when sulfite was used as a preservative

Gender differences in the relationship between sleep problems and suicide attempt in adolescents

© 2020 The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3389/fpsyt.2020.00133© Copyright © 2020 Wan, Xu, Wang, Boyda, Mcfeeters, Sun, Zhang, Chen and Tao. There are few studies examining which types of sleep problems are independently associated with suicide attempt (SA) and gender difference in adolescents. The aim of the present study was to examine whether specific sleep problems were uniquely associated with suicide attempt in adolescents and explore gender differences in the association. A school-based health survey was conducted in four provinces within China from November 2014 to January 2015. A total of 15,132 students aged 10–21 years completed standard questionnaires assessing past 12 month suicide attempt in addition to measures of sleep quality, quantity and sleep beliefs. 5.4% of participants reported a suicide attempt within the last 12 months. After adjustment for sociodemographic variables and psychological symptoms, almost all sleep problems remained significantly associated with a greater endorsement of suicide attempt. Further adjustment for co-occurring sleep problems revealed that weekday sleep duration (<6, 8–10, and ≥10 h), insomnia (often), and nightmares (sometimes and often) remained independently associated with suicide attempt in boys (p < 0.05). However in girls, weekday sleep duration (<6 and ≥10 h), weekend sleep duration (<6 h), midday nap (0 or 1–2 d/week), insomnia (sometimes and often), nightmare (often) and sleep beliefs (high) were independently associated with suicide attempt (p < 0.05). Multiple sleep problems are associated with suicide attempt in adolescents, however the relationship varies by gender.Funding for the project was provided by National Natural Science Foundation of China (81773453 and 81202223) and Natural Science Foundation of Anhui province (1708085QH223).Published versio

Effect of Skin Wine Pomace and Sulfite on Protein Oxidation in Beef Patties During High Oxygen Atmosphere Storage

Meat storage in high oxygen atmosphere has been reported to induce protein oxidation reactions decreasing meat quality. The incorporation of antioxidants has been proposed to reduce the extent of these reactions. In this study, the ability of red and white skin wine pomaces as well as sulfites to inhibit protein oxidation were tested in beef patties stored for up to 15 days at 4 °C in a high oxygen atmosphere (70 % O2 and 30 % CO2). SO2 (300 ppm) effectively protected against protein oxidation measured as radical formation by electron spin resonance (ESR) spectroscopy, as thiol loss by the DTNB assay and as myosin heavy chain (MHC) disulfide crosslinking by SDS-PAGE. Pomace from red wine production with a total phenol of 9.9 mg gallic acid equivalent/g protected against protein radical formation and against MHC crosslinking, but not against thiol loss by addition of 2.0 % (w/w) to the beef patties. Pomace from white wine production with a total phenol of 4.0 mg gallic acid equivalent/g only protected against MHC cross-linking. For both types of wine pomace, protein modifications not seen for sulfite addition were observed and were proposed to involve covalent phenol addition to proteins. Red wine pomace may be an alternative to sulfite as a meat additive for protection of beef patties against protein oxidation.Autonomous Government of Castilla y León through the research projects (BU268A11-2 and BU282U13) and the Danish Council for Independent Research |Technology and Production within the Danish Agency for Science Technology and Innovation for granting the project entitled: BAntioxidant mechanisms of natural phenolic compounds against protein cross-link formation in meat and meat systems^ (11-117033)

Protective Effects of Organic Acids on Survival of Escherichia coli O157:H7 in Acidic Environments

Outbreaks of disease due to acid-tolerant bacterial pathogens in apple cider and orange juice have raised questions about the safety of acidified foods. Using gluconic acid as a noninhibitory low-pH buffer, we investigated the killing of Escherichia coli O157:H7 strains in the presence or absence of selected organic acids (pH of 3.2), with ionic strength adjusted to 0.60 to 0.68. During a 6-h exposure period in buffered solution (pH 3.2), we found that a population of acid-adapted E. coli O157:H7 strains was reduced by 4 log cycles in the absence of added organic acids. Surprisingly, reduced lethality for E. coli O157:H7 was observed when low concentrations (5 mM) of fully protonated acetic, malic, or l-lactic acid were added. Only a 2- to 3-log reduction in cell counts was observed, instead of the 4-log reduction attributed to pH effects in the buffered solution. Higher concentrations of these acids at the same pH aided in the killing of the E. coli cells, resulting in a 6-log or greater reduction in cell numbers. No protective effect was observed when citric acid was added to the E. coli cells. d-Lactic acid had a greater protective effect than other acids at concentrations of 1 to 20 mM. Less than a 1-log decrease in cell numbers occurred during the 6-h exposure to pH 3.2. To our knowledge, this is the first report of the protective effect of organic acids on the survival of E. coli O15:H7 under low-pH conditions