Exercise enhances placental labyrinth trophoblast development by activation of PGC-1α and FNDC5/irisin†.

Placental chorion/labyrinth trophoblasts are energy demanding which is met by the mitochondrial oxidative phosphorylation. Exercise enhances placental development and mitochondrial biogenesis, but the underlying mechanisms remain poorly understood. To address, female C57BL/6 J mice were randomly assigned into two groups: a control group and an exercise (EX) group. All animals were acclimated to treadmill exercise for 1 week before mating, but only the EX group was subjected to daily exercise during pregnancy from embryonic day (E) 1.5 to E16.5. Placenta were collected at E18.5 for biochemical and histochemical analyses, and primary trophoblast cells were isolated from the E18.5 placenta for further analyses. The data showed that exercise during pregnancy promoted the expression of syncytiotrophoblast cell markers, indicating trophoblast cell differentiation, which was closely associated with elevated mitochondrial biogenesis and oxidative metabolism in the E18.5 placenta. In addition, exercise during pregnancy activated peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α), which was associated with upregulated placental α-ketoglutarate and the expression of isocitrate dehydrogenases and ten-eleven translocations, facilitating DNA demethylation of the Pgc1a promoter. Furthermore, exercise upregulated fibronectin type III domain containing 5 expression and the secretion of its cleaved form, irisin, which is known to activate PGC-1α. These data suggest that exercise-induced activation of PGC-1α, via epigenetic modifications, is responsible for promoting mitochondrial energy metabolism and chorion/labyrinth trophoblast development.

Comprehensive strategies for controlling Listeria monocytogenes biofilms on food-contact surfaces.

Listeria monocytogenes biofilms formed on food-contact surfaces within food-processing facilities pose a significant challenge, serving as persistent sources of cross-contamination. In this review, we examined documented cases of foodborne outbreaks and recalls linked to L. monocytogenes contamination on equipment surfaces and in the food production environment, provided an overview of the prevalence and persistence of L. monocytogenes in different food-processing facilities, and discussed environmental factors influencing its biofilm formation. We further delved into antimicrobial interventions, such as chemical sanitizers, thermal treatments, biological control, physical treatment, and other approaches for controlling L. monocytogenes biofilms on food-contact surfaces. This review provides valuable insights into the persistent challenge of L. monocytogenes biofilms in food processing, offering a foundation for future research and practical strategies to enhance food safety.

Exercise improves homeostasis of the intestinal epithelium by activation of apelin receptor-AMP-activated protein kinase signalling.

Intestinal remodelling is dynamically regulated by energy metabolism. Exercise is beneficial for gut health, but the specific mechanisms remain poorly understood. Intestine-specific apelin receptor (APJ) knockdown (KD) and wild-type male mice were randomly divided into two subgroups, with/without exercise, to obtain four groups: WT, WT with exercise, APJ KD and APJ KD with exercise. Animals in the exercise groups were subjected to daily treadmill exercise for 3 weeks. Duodenum was collected at 48 h after the last bout of exercise. AMP-activated protein kinase (AMPK) α1 KD and wild-type mice were also utilized for investigating the mediatory role of AMPK on exercise-induced duodenal epithelial development. AMPK and peroxisome proliferator-activated receptor γ coactivator-1 α were upregulated by exercise via APJ activation in the intestinal duodenum. Correspondingly, exercise induced permissive histone modifications in the PR domain containing 16 (PRDM16) promoter to activate its expression, which was dependent on APJ activation. In agreement, exercise elevated the expression of mitochondrial oxidative markers. The expression of intestinal epithelial markers was downregulated due to AMPK deficiency, and AMPK signalling facilitated epithelial renewal. These data demonstrate that exercise-induced activation of the APJ-AMPK axis facilitates the homeostasis of the intestinal duodenal epithelium. KEY POINTS: Apelin receptor (APJ) signalling is required for improved epithelial homeostasis of the small intestine in response to exercise. Exercise intervention activates PRDM16 through inducing histone modifications, enhanced mitochondrial biogenesis and fatty acid metabolism in duodenum. The morphological development of duodenal villus and crypt is enhanced by the muscle-derived exerkine apelin through the APJ-AMP-activated protein kinase axis.

Unraveling enterohemorrhagic Escherichia coli infection: the promising role of dietary compounds and probiotics in bacterial elimination and host innate immunity boosting.

The innate immune system has developed sophisticated strategies to defense against infections. Host cells utilize the recognition machineries such as toll-like receptors and nucleotide binding and oligomerization domain-like receptors to identify the pathogens and alert immune system. However, some pathogens have developed tactics to evade host defenses, including manipulation of host inflammatory response, interference with cell death pathway, and highjack of phagocytosis signaling for a better survival and colonization in host. Enterohemorrhagic Escherichia coli (EHEC) is a notorious foodborne pathogen that causes severe tissue damages and gastrointestinal diseases, which has been reported to disturb host immune responses. Diverse bioactive compounds such as flavonoids, phenolic acids, alkaloids, saccharides, and terpenoids derived from food varieties and probiotics have been discovered and investigated for their capability of combating bacterial infections. Some of them serve as novel antimicrobial agents and act as immune boosters that harness host immune system. In this review, we will discuss how EHEC, specifically E. coli O157:H7, hijacks the host immune system and interferes with host signaling pathway; and highlight the promising role of food-derived bioactive compounds and probiotics in harnessing host innate immunity and eliminating E. coli O157:H7 infection with multiple strategies.

Prebiotic effects of goji berry in protection against inflammatory bowel disease.

The prevalence of inflammatory bowel disease (IBD) is increasing, which is concerning because IBD is a known risk factor for the development of colorectal cancer. Emerging evidence highlights environmental factors, particularly dietary factors and gut microbiota dysbiosis, as pivotal inducers of IBD onset. Goji berry, an ancient tonic food and a nutraceutical supplement, contains a range of phytochemicals such as polysaccharides, carotenoids, and polyphenols. Among these phytochemicals, L. barbarum polysaccharides (LBPs) are the most important functional constituents, which have protective effects against oxidative stress, inflammation, and neurodegeneration. Recently, the beneficial effects of goji berry and associated LBPs consumption were linked to prebiotic effects, which can prevent dysbiosis associated with IBD. This review assessed pertinent literature on the protective effects of goji berry against IBD focusing on the gut microbiota and their metabolites in mediating the observed beneficial effects.

Enhancing the efficacy of peracetic acid against Listeria monocytogenes and Listeria innocua on fresh apples using commercial acidic and alkaline cleaners.

Peracetic acid (PAA) is a commonly used antimicrobial in brush-bed spray bar interventions during apple packing. Prior to sanitizer application on the brush-bed, specific fruit cleaners, such as Acidex Duo (AD), EpiClean (EC), Nature's Shield 220-ACL (NS 220), or Nature's Shield 330-ALK (NS 330), are used to remove of soil, debris, and natural wax from the surfaces of apples. This study evaluated the effectiveness of commonly used cleaners in the apple industry to improve the antimicrobial efficacy of PAA against Listeria monocytogenes on apple surfaces during brush-bed spray bar interventions. Granny Smith apples, 48 h post-inoculation, underwent submersion treatment with different cleaners, as well as PAA alone or in combination with the cleaners. A 30-sec treatment of 5.0% AD, 4.2% EC, 10.0% NS 220, and 10.0% NS 330 resulted in 0.65, 0.50, 0.68, and 0.51 log10 CFU/apple reduction of L. monocytogenes on apples, respectively. Incorporating AD, NS 220, and EC significantly enhanced the antimicrobial efficacy of an 80 ppm PAA intervention. The enhancing effects were not impacted whether the cleaner was applied consecutively with PAA (sequentially) or in combination with PAA (simultaneously), nor were they impacted by a post-treatment water rinse. A 30-120 s wash of 80 ppm PAA with AD, EC, and NS 220 at their suggested concentration resulted in 2.46-2.55, 1.87-2.03, and 2.34-2.48 log10 CFU/apple reduction of L. monocytogenes, respectively, compared to 1.39-1.64 log10 CFU/apple in PAA treatment alone. The inclusion of AD or NS 220 in 80 ppm PAA solution resulted in a reduction of 1.51-1.63 log10 CFU/apple of Listeria after 30-60 s brush-bed spray wash. This enhancement in efficacy was significant compared to the treatment with 80 ppm PAA alone, which resulted in a reduction of 0.94-1.03 log10 CFU/apple. This study demonstrated that using certain commercially available cleaners along with PAA can enhance the effectiveness of PAA in reducing L. monocytogenes on fresh apples.

Listeria monocytogenes cross-contamination during apple waxing and subsequent survival under different storage conditions.

This study evaluated Listeria monocytogenes cross-contamination between inoculated fruits, waxing brush, and uninoculated fruits during apple wax coating and investigated the fate of L. monocytogenes on wax-coated apples introduced via different wax coating schemes. There were 1.8-1.9 log10 CFU/apple reductions of L. monocytogenes on PrimaFresh 360, PrimaFresh 606, or Shield-Brite AP-450 coated apples introduced before wax coating after 6 weeks of ambient storage (22 °C and ambient relative humidity). L. monocytogenes showed a similar trend (P > 0.05) on waxed apples under cold storage (1 °C and ∼ 90% relative humidity); there were 1.8-2.0 log10 CFU/apple reductions of L. monocytogenes during the 12 weeks of cold storage regardless of wax coating type. For cross-contamination study, a waxing brush was used to wax one inoculated apple (6.2 log10 CFU/apple); then, this brush was used to wax five uninoculated apples in a sequence. There were 3.7, 3.5, 3.3, 2.9, and 2.7 log10 CFU/apple and 3.6 log10 CFU/brush of L. monocytogenes transferred from the inoculated apple to uninoculated apple 1 to apple 5, and the waxing brush, respectively. The die-off rate of L. monocytogenes on wax-coated apples contaminated during wax coating was not significantly different from that contaminated on apples before wax coating, and 1.8-1.9 log10 CFU/apple reductions were observed during the 12 weeks of cold storage. The application of wax coatings, regardless of wax coating type, did not impact the survival of endogenous yeasts and molds on apples during ambient or cold storage. L. monocytogenes transferred onto waxing brushes during wax coating remained relatively stable during the 2-week ambient holding. Fungicide application during wax coating reduced (P < 0.05) yeast and mold counts but had a minor impact (P > 0.05) on the survival of L. monocytogenes on apples after 12 weeks of cold storage. Collectively, this study indicated that a high cross-contamination risk of L. monocytogenes during apple waxing, and L. monocytogenes on wax-coated apples introduced via different scenarios is stable during subsequent cold storage, highlighting the need for potential intervention strategies to control L. monocytogenes on wax-coated apples.

Exerkine apelin reverses obesity-associated placental dysfunction by accelerating mitochondrial biogenesis in mice.

Maternal exercise (ME) protects against adverse effects of maternal obesity (MO) on fetal development. As a cytokine stimulated by exercise, apelin (APN) is elevated due to ME, but its roles in mediating the effects of ME on placental development remain to be defined. Two studies were conducted. In the first study, 18 female mice were assigned to control (CON), obesogenic diet (OB), or OB with exercise (OB/Ex) groups (n = 6); in the second study, the same number of female mice were assigned to three groups; CON with PBS injection (CD/PBS), OB/PBS, or OB with apelin injection (OB/APN). In the exercise study, daily treadmill exercise during pregnancy significantly elevated the expression of PR domain 16 (PRDM16; P < 0.001), which correlated with enhanced oxidative metabolism and mitochondrial biogenesis in the placenta (P < 0.05). More importantly, these changes were partially mirrored in the apelin study. Apelin administration upregulated PRDM16 protein level (P < 0.001), mitochondrial biogenesis (P < 0.05), placental nutrient transporter expression (P < 0.001), and placental vascularization (P < 0.01), which were impaired due to MO (P < 0.05). In summary, MO impairs oxidative phosphorylation in the placenta, which is improved by ME; apelin administration partially mimics the beneficial effects of exercise on improving placental function, which prevents placental dysfunction due to MO.NEW & NOTEWORTHY Maternal exercise prevents metabolic disorders of mothers and offspring induced by high-fat diet. Exercise intervention enhances PRDM16 activation, oxidative metabolism, and vascularization of placenta, which are inhibited due to maternal obesity. Similar to maternal exercise, apelin administration improves placental function of obese dams.

Maternal exercise improves epithelial development of fetal intestine by enhancing apelin signaling and oxidative metabolism.

Obesity in pregnancy is currently the leading cause of gestational complications for the mother and fetus worldwide. Maternal obesity (MO), common in western societies, impedes development of intestinal epithelium in the fetuses, which causes disorders in the nutrient absorption and intestine-related immune responses in offspring. Here, using a mouse model of maternal exercise (ME), we found that exercise during pregnancy protects the impairment of fetal intestinal morphometrical formation and epithelial development due to MO. MO decreased villus length and epithelial proliferation markers in E18.5 fetal small intestine, which was increased due to ME. The expression of the epithelial differentiation markers, Lyz1, Muc2, and Tff3, in fetal small intestine was decreased due to MO, but protected by ME. Consistently, the biomarkers related to mitochondrial biogenesis and oxidative metabolism were downregulated in MO fetal small intestine but recovered by ME. Apelin injection to dams partially mirrored the beneficial effects of ME. ME and apelin injection activated AMPK, the downstream target of apelin receptor signaling, which might mediate the improvement of fetal epithelial development and oxidative metabolism. These findings suggest that ME, a highly accessible intervention, is effective in improving fetal intestinal epithelium of obese dams. Apelin-AMPK-mitochondrial biogenesis axis provides amenable therapeutic targets to facilitate fetal intestinal development of obese mothers.

Control of Salmonella in low-moisture foods: Enterococcus faecium NRRL B-2354 as a surrogate for thermal and non-thermal validation.

Salmonella has been implicated in multiple foodborne outbreaks and recalls associated with low water activity foods (LawF). To verify the effectiveness of a process against Salmonella in LawF, validation using a nonpathogenic surrogate strain is essential. Enterococcus faecium NRRL B-2354 strain has been used as a potential surrogate of Salmonella in different processing of LawF. However, the survival of Salmonella and E. faecium in LawF during food processing is a dynamic function of aw, food composition and structure, processing techniques, and other factors. This review assessed pertinent literature on the thermal and non-thermal inactivation of Salmonella and its presumable surrogate E. faecium in various LawF and provided an overview of its suitibility in different LawF. Overall, based on the D-values, survival/reduction, temperature/time to obtain 4 or 5-log reductions, most studies concluded that E. faecium is a suitable surrogate of Salmonella during LawF processing as its magnitude of resistance was slightly greater or equal (i.e., statistical similar) as compared to Salmonella. Studies also showed its unsuitability which either does not provide a proper margin of safety or being overly resistant and may compromise the quality and organoleptic properties of food. This review provides useful information and guidance for future validation studies of LawF.

Vitamin a supplementation during pregnancy in shaping child growth outcomes: A meta-analysis.

Abnormal fetal growth increases risks of childhood health complications. Vitamin A supplementation (VAS) is highly accessible, but literature inconsistency regarding effects of maternal VAS on fetal and childhood growth outcomes exists, deterring pregnant women from VAS during pregnancy. This meta-analysis aimed to analyze effects of vitamin A only or vitamin A + co-intervention during pregnancy in healthy mothers (MH) or with complications (MC, night blindness and HIV positive) on perinatal growth outcomes, also assess VAS dose impacts. The Cochrane Library, PubMed, ScienceDirect, Scopus, Embase and Web of Science databases were searched from inception to July 15, 2021. We covered subgroup analyses, including VAS in MH or MC within randomized controlled trial (RCT) or observational studies (OS). Fifty-five studies were included in this meta-analysis (426,098 pregnancies). Vitamin A decreased risk of preterm birth by 9% in MH-RCT (P < 0.001), by 62% in MH-OS (P = 0.029), by 10% in MC-RCT (P = 0.089); decreased LBW by 24% in MC-RCT (P = 0.032); increased neonatal weight in MC-RCT (SMD 0.96; P = 0.051). Besides, vitamin A + co-intervention decreased risks of preterm by 18% in MH-OS (P = 0.021); LBW by 25% in MH-OS (P < 0.001); by 32% in MC-RCT (P = 0.006); decreased neonatal defects by 33% in MH-OS (P = 0.064); decreased anemia by 25% in MH-OS (P = 0.0003); increased neonatal weight in MH-OS (SMD 0.51; P = 0.014); and increased neonatal length in MH-OS (SMD 1.83; P = 0.013). Meta-regression of VAS dose with individual outcomes was not significant, and no side effects were observed for VAS doses up to 4000 mcg (RAE/d). Regardless of maternal health conditions, VAS during pregnancy can safely and effectively improve fetal development and neonatal health even in mothers without VAD.

Efficacy of chlorine and peroxyacetic acid to control Listeria monocytogenes on apples in simulated dump tank water system.

Chlorine and peroxyacetic acid (PAA) are commonly applied in dump tanks and flume systems in commercial fresh apple packing lines; however, little is known about their practical efficacies in dump tank water systems. This study evaluated the efficacies of chlorine and PAA to control Listeria monocytogenes on fresh apples and cross-contamination in simulated dump tank water (SDTW). Efficacies of chlorinated water with initial free chlorine (FC) of 25-100 ppm against L. monocytogenes on apples were significantly impacted by the presence of organic matter, especially for chlorine with 25 ppm initial FC. Chlorine with initial FCs of 50-100 ppm and 2 min contact reduced L. monocytogenes on apples by ∼0.9 log10 CFU/apple in SDTW with 1000 ppm chemical oxygen demand (COD). However, 2-5 min wash of chlorine with 25 ppm initial FC only led to ∼0.3 log10 CFU/apple reduction of L. monocytogenes on apples in SDTW compared to ∼0.9 log10 CFU/apple reduction in clean water. The impacts of organic matter on the antimicrobial efficacy of PAA are concentration dependent. At 20-80 ppm and tested contact times (2-5 min), efficacies of PAA against L. monocytogenes were not influenced by organic matter presented in SDTW; 2-5 min wash with PAA 80 ppm caused 1.7-1.8 log10 CFU/apple log reduction. However, the anti-Listeria efficacy of 10 ppm PAA was significantly lower in SDTW than in clean water. Sanitizers at the tested concentrations reduced L. monocytogenes transferred from contaminated apples to uncontaminated apples and SDTW but did not eliminate it. There were 1.7-0.6 and 1.0-0.9 log10 CFU/apple of L. monocytogenes transferred to uninoculated apples in SDTW treated with 50-100 ppm FC and 60-80 ppm PAA, respectively, for 2 min, while 3.6-3.7 log10 CFU/apple of L. monocytogenes were transferred to uncontaminated apples in SDTW without any sanitizer treatments. Data indicated that sanitizer treatments in SDTW are effective but can be further improved to ensure the microbial safety of apples.

Effects of 1-methylcyclopropene and gaseous ozone on Listeria innocua survival and fruit quality of Granny Smith apples during long-term commercial cold storage.

This study evaluated the impact of 1-methylcyclopropene (1-MCP), an ethylene synthesis inhibitor, followed by long-term commercial cold storage with low-dose gaseous ozone on the microbiological safety and quality of fresh apples. Granny Smith apples were inoculated with or without Listeria innocua, treated with or without 1.0 mg/L 1-MCP for 24 h, then subjected to commercial cold storage conditions including refrigerated air (RA, 0.6 °C, control), controlled atmosphere (CA, 2% O2, 1% CO2, 0.6 °C), and CA with 51-87 µg/L ozone gas for up to 36 weeks. RA storage reduced L. innocua on apples by up to 3.6 log10 CFU/apple. CA had no advantage over RA in controlling Listeria. Continuous ozone gas application resulted in an additional ∼2.0 log10 CFU/apple reduction of L. innocua (total reduction up to 5.7 log10 CFU/apple) and suppressed native bacteria and fungi. Treatment with 1-MCP had a minor impact on survival of L. innocua or background microbiota on apples, while it significantly delayed fruit ripening and reduced the incidence of superficial scald and internal browning. In summary, 1-MCP treatment followed by CA storage with low-dose continuous ozone gas can effectively control Listeria on fresh apples and delay fruit ripening.

High-pressure pasteurization of low-acid chilled ready-to-eat food.

The working population growth have created greater consumer demand for ready-to-eat (RTE) foods. Pasteurization is one of the most common preservation methods for commercial production of low-acid RTE cold-chain products. Proper selection of a pasteurization method plays an important role not only in ensuring microbial safety but also in maintaining food quality during storage. Better retention of flavor, color, appearance, and nutritional value of RTE products is one of the reasons for the food industry to adopt novel technologies such as high-pressure processing (HPP) as a substitute or complementary technology for thermal pasteurization. HPP has been used industrially for the pasteurization of high-acid RTE products. Yet, this method is not commonly used for pasteurization of low-acid RTE food products, due primarily to the need of additional heating to thermally inactivate spores, coupled with relatively long treatment times resulting in high processing costs. Practical Application: Food companies would like to adopt novel technologies such as HPP instead of using conventional thermal processes, yet there is a lack of information on spoilage and the shelf-life of pasteurized low-acid RTE foods (by different novel pasteurization methods including HPP) in cold storage. This article provides an overview of the microbial concerns and related regulatory guidelines for the pasteurization of low-acid RTE foods and summarizes the effects of HPP in terms of microbiology (both pathogens and spoilage microorganisms), quality, and shelf-life on low-acid RTE foods. This review also includes the most recent research articles regarding a comparison between HPP pasteurization and thermal pasteurization treatments and the limitations of HPP for low-acid chilled RTE foods.

Moisture Content of Bacterial Cells Determines Thermal Resistance of Salmonella enterica Serotype Enteritidis PT 30.

Salmonella spp. are resilient bacterial pathogens in low-moisture foods. There has been a general lack of understanding of critical factors contributing to the enhanced thermal tolerance of Salmonella spp. in dry environments. In this study, we hypothesized that the moisture content (XW ) of bacterial cells is a critical intrinsic factor influencing the resistance of Salmonella spp. to thermal inactivation. We selected Salmonella enterica serotype Enteritidis PT 30 to test this hypothesis. We first produced viable freeze-dried S. Enteritidis PT 30, conditioned the bacterial cells to different XW s (7.7, 9.2, 12.4, and 15.7 g water/100 g dry solids), and determined the thermal inactivation kinetics of those cells at 80°C. The results show that the D-value (the time required to achieve a 1-log reduction) decreased exponentially with increasing XW We further measured the water activities (aw) of the freeze-dried S. Enteritidis PT 30 as influenced by temperatures between 20 and 80°C. By using those data, we estimated the XW of S. Enteritidis PT 30 from the published papers that related the D-values of the same bacterial strain at 80°C with the aw of five different food and silicon dioxide matrices. We discovered that the logarithmic D-values of S. Enteritidis PT 30 in all those matrices also decreased linearly with increasing XW of the bacterial cells. The findings suggest that the amount of moisture in S. Enteritidis PT 30 is a determining factor of its ability to resist thermal inactivation. Our results may help future research into fundamental mechanisms for thermal inactivation of bacterial pathogens in dry environments.IMPORTANCE This study established a logarithmic relationship between the thermal death time (D-value) of S. Enteritidis PT 30 and the moisture content (XW ) of the bacterial cells by conducting thermal inactivation tests on freeze-dried S Enteritidis PT 30. We further verified this relationship using literature data for S. Enteritidis PT 30 in five low-moisture matrices. The findings suggest that the XW of S. Enteritidis PT 30, which is rapidly adjusted by microenvironmental aw, or relative humidity, during heat treatments, is the key intrinsic factor determining the thermal resistance of the bacterium. The quantitative relationships reported in this study may help guide future designs of industrial thermal processes for the control of S. Enteritidis PT 30 or other Salmonella strains in low-moisture foods. Our findings highlight a need for further fundamental investigation into the role of water in protein denaturation and the accumulation of compatible solutes during thermal inactivation of bacterial pathogens in dry environments.

Hop bioactive compounds in prevention of nutrition-related noncommunicable diseases.

Nutrition-related noncommunicable diseases (NR-NCDs) such as cardiovascular disease and type 2 diabetes both negatively impact the quality of life of many individuals and generate a substantial burden on society, demonstrating a need for intervention. Phytochemicals are investigated as a potential approach for combating NR-NCDs, and those found in hops have gained increased attention in recent decades. Hops, the strobile of the plant Humulus lupulus, are grown primarily for the brewing industry as they confer taste and increased shelf-life. The bitter acids represent the main compounds of interest for improving beer quality. Additionally, bitter acids as well as the prenylated chalcone xanthohumol, exhibit a wide range of health beneficial properties. This review summarizes those beneficial effects of bitter acids and xanthohumol on NR-NCDs, including inflammatory and immune diseases, obesity and metabolic disorders, as well as cancer prevention.

Practical in-storage interventions to control foodborne pathogens on fresh produce.

Although tremendous efforts have been made to ensure fresh produce safety, various foodborne outbreaks and recalls occur annually. Most of the current intervention strategies are evaluated within a short timeframe (less than 1 h), leaving the behavior of the remaining pathogens unknown during subsequent storages. This review summarized outbreak and recall surveillance data from 2009 to 2018 obtained from government agencies in the United States to identify major safety concerns associated with fresh produce, discussed the postharvest handling of fresh produce and the limitations of current antimicrobial interventions, and reviewed the intervention strategies that have the potential to be applied in each storage stage at the commercial scale. One long-term (up to 12 months) prepacking storage (apples, pears, citrus among others) and three short-term (up to 3 months) postpacking storages were identified. During the prepacking storage, continuous application of gaseous ozone at low doses (≤1 ppm) is a feasible option. Proper concentration, adequate circulation, as well as excess gas destruction and ventilation systems are essential to commercial application. At the postpacking storage stages, continuous inhibition can be achieved through controlled release of gaseous chlorine dioxide in packaging, antimicrobial edible coatings, and biocontrol agents. During commercialization, factors that need to be taken into consideration include physicochemical properties of antimicrobials, impacts on fresh produce quality and sensory attributes, recontamination and cross-contamination, cost, and feasibility of large-scale production. To improve fresh produce safety and quality during storage, the collaboration between researchers and the fresh produce industry needs to be improved.

Even a low dose of tamoxifen profoundly induces adipose tissue browning in female mice.

BACKGROUND: Tamoxifen-inducible Cre/lox site-specific recombination technology has been widely used to generate conditional transgenic mice. As an estrogen receptor ligand, tamoxifen itself potentially affects energy metabolism, which may confound interpretation of data especially in metabolic studies. Considering sexual dimorphism, in this study, the effects of low-dose tamoxifen administration on energy metabolism, and browning of adipose tissues in female and male mice were investigated. METHODS: Female and male C57/BL6 mice were injected with tamoxifen oil solution (i.p.) and then housed at both room temperature (23 ± 2 °C) and cold environment (6 ± 1 °C). Serum, brown and white adipose tissues were obtained, and the effects of tamoxifen administration on energy metabolism and the browning of adipose tissues were evaluated. RESULTS: At 25 mg/kg body weight (BDW), tamoxifen administration for 3 alternative days decreased the percentage of inguinal and gonadal white adipose tissue weights in female mice accompanied by the up-regulation of thermogenesis in adipose tissues. In contrast, this dosage of tamoxifen did not induce noticeable changes in the energy metabolism and thermogenesis of adipose tissue in male mice under room temperature. Consistently, under cold stimulus, substantial browning of adipose tissues was observed in female mice injected with tamoxifen (50 mg/kg BDW, single injection) but not in male mice. Two-way ANOVA tests also demonstrated significant interactions between tamoxifen treatment and gender on the expression of thermogenic markers in adipose tissues. CONCLUSION: Tamoxifen, even at a low dose, remarkably increases thermogenesis in adipose tissues of female mice; meanwhile, such a low dose could be used in male mice for inducing gene recombination without confounding the interpretation of data related to metabolism and thermogenesis of adipose tissues.

The efficacy of sodium acid sulfate on controlling Listeria monocytogenes on apples in a water system with organic matter.

During fresh apple packing, wash water in the dump tank and flume systems is reused during daily production, resulting in high levels of organic matter in the wash water. This study evaluated the antimicrobial efficacy of sodium acid sulfate (SAS), a Generally Recognized as Safe compound, against Listeria monocytogenes on fresh apples in a water system with high organic load. SAS at 1.0% reduced L. monocytogenes population in water with 1000 ppm chemical oxygen demand (COD) by more than 5.0 Log10 CFU/ml in 5 min, 2.0-3.0% SAS reduced L. monocytogenes to undetectable levels (10 CFU/ml) within 2 min regardless of organic levels. When applied on apples, a 2-min wash with SAS at 1.0, 1.5, 2.0, and 3.0% reduced L. monocytogenes by ~1.3, 1.9, 2.3, and 3.0 Log10 CFU/apple in clean water, respectively. High organic load in wash water up to 4000 ppm COD had no impact on the bactericidal effect of SAS against L. monocytogenes on fresh apples regardless of SAS concentrations. Shortening the contact time from 2 min to 30 s significantly reduced the antimicrobial efficacy of 25 ppm chlorine and 1.0-2.0% SAS but not that of 3.0% SAS. In addition, SAS at 1.0% demonstrated a better efficacy than 25 ppm chlorine in reducing fruit-to-water cross-contamination regardless of organic matter. SAS also showed a comparable efficacy as 25 ppm chlorine in reducing fruit-to-fruit cross-contamination in water with organic matter. The collective data indicate that SAS, as an enviroment-friendly compound, has the potential to be used as an alternative antimicrobial washing aid in dump tank process water intervention in apple packing facilities.

Stability of Listeria monocytogenes in non-fat dry milk powder during isothermal treatment and storage.

Dry dairy powder is a commonly used ingredient for ready-to-eat foods. It has been implicated in multiple foodborne outbreaks. Listeria monocytogenes can survive in low-moisture conditions for a long duration. However, there is no information on Listeria survival in dry milk powder during storage and thermal treatments. The objectives of this study were to examine the stability of L. monocytogenes in non-fat dry milk (NFDM) during extended storage and further analyze thermal resistance of L. monocytogenes in NFDM under different water activities (aw) and its thermal stability after 1-year storage. We observed approximately 1.75 and 2.93 log CFU/g reduction of L. monocytogenes in aw 0.25 NFDM over 1-year storage at 4 and 22 °C, respectively. Thermal resistance of L. monocytogenes was inversely related to aw, and the inactivation kinetic curves of L. monocytogenes in NFDM at target aw showed a log-linear trend under all tested conditions. For aw 0.25, 0.30, and 0.45 NFDM, the ranges of D-values, were 66.2-21.3, 33.5-9.4, and 14.6-4.3 min at 70, 75 and 80 °C, respectively. The z-values for L. monocytogenes in NFDM at aw 0.25-0.45 were 14.6-16.0 C°. Furthermore, the thermal stability of L. monocytogenes in aw 0.25 NFDM post 6-month or 12-month storage under refrigerated or ambient temperature did not deviate much from that in NFDM prior to the storage. Data indicated that a 60-min heat treatment at 80 °C resulted in ~ 5-log reduction of L. monocytogenes in NFDM of aw 0.30. This provides a promising intervention strategy to enhance bactericidal efficacy of thermal treatment while maintaining the quality of milk powder.