Antimicrobial properties of Limosilactobacillus reuteri strains for control of Escherichia coli and Salmonella strains, diarrhoea cause in weaning pigs.

This study aimed to use lactic acid bacteria isolated from piglet faeces to develop probiotics, allowing for the effective control of Escherichia coli and Salmonella. Lactic acid bacteria were isolated from the faeces of suckling piglets and identified by 16S rRNA sequencing, then examined for haemolysis; gelatinase activity; and resistance to acid, bile, and pancreatin. The antimicrobial activity of selected lactic acid bacteria isolates was examined for 8 E. coli and 7 Salmonella strains. One-hundred and sixty-four lactic acid bacteria isolates were identified from 118 piglet faecal samples, and 13 lactic acid bacteria isolates were selected from analyses of haemolysis; gelatinase activity; and resistance to acid, bile, and pancreatin. Of the selected 13 lactic acid bacteria isolates, Limosilactobacillus reuteri PF20-3 and PF30-3 strains had the highest antibacterial activity against E. coli and Salmonella.

Effects of dietary supplementation of Pediococcus pentosaceus strains from kimchi in weaned piglet challenged with Escherichia coli and Salmonella enterica.

Escherichia coli (E. coli) and Salmonella enterica (SE) infections in pigs are major source associated with enteric disease such as post weaning diarrhea. The aim of this study was to investigate the effects of Pediococcus pentosaceus in weaned piglets challenged with pathogen bacteria. In Experiment.1 90 weaned piglets with initial body weights of 8.53 ± 0.34 kg were assigned to 15 treatments for 2 weeks. The experiments were conducted two trials in a 2 × 5 factorial arrangement of treatments consisting of two levels of challenge (challenge and non-challenge) with E. coli and SE, respectively and five levels of probiotics (Control, Lactobacillus plantarum [LA], Pediococcus pentosaceus SMFM2016-WK1 [38W], Pediococcus acidilactici K [PK], Lactobacillus reuteri PF30 [PF30]). In Experiment.2 a total of 30 weaned pigs (initial body weight of 9.84 ± 0.85 kg) were used in 4 weeks experiment. Pigs were allocated to 5 groups in a randomized complete way with 2 pens per group and 3 pigs per pen. Supplementation of LA and 38W improved (p < 0.05) growth performance, intestinal pathogen bacteria count, fecal noxious odor and diarrhea incidence. In conclusion, supplementation of 38W strains isolated from white kimchi can act as probiotics by inhibiting E. coli and SE.

Isolation of Debaryomyces hansenii and selection of an optimal strain to improve the quality of low-grade beef rump (middle gluteal) during dry aging.

OBJECTIVE: The objective of this study was to evaluate the effect of Debaryomyces hansenii isolated from dry-aged beef on the tenderness and flavor attributes of low-grade beef during dry aging. METHODS: Five D. hansenii strains were isolated from dry-aged beef samples. The rump of low-grade beef was inoculated with individual D. hansenii isolates and subjected to dry aging for 4 weeks at 5°C and 75% relative humidity. Microbial contamination levels, meat quality attributes, and flavor attributes in the dry-aged beef were measured. RESULTS: Of the five isolates, the shear force of dry-aged beef inoculated with SMFM201812-3 and SMFM201905-5 was lower than that of control samples. Meanwhile, all five isolates increased the total free amino acid, glutamic acid, serine, glycine, alanine, and leucine contents in dry-aged beef. In particular, the total fatty acid, palmitic acid, and oleic acid contents in samples inoculated with D. hansenii SMFM201905-5 were higher than those in control samples. CONCLUSION: These results indicate that D. hansenii SMFM201905-5 might be used to improve the quality of beef during dry aging.

siRNAs to Knockdown Antiviral Chemokine-related Genes in FRhK-4 Cells.

The objective of this study was to generate small interfering RNA (siRNA) to knockdown antiviral chemokine-related genes in fetal rhesus monkey kidney (FRhK-4) cells. We generated siRNA duplexes to suppress antiviral chemokines like CXCL10 and CCL4 in FRhK-4 cells by downregulating interferon regulatory factor (IRF) 3 and IRF7. Three siRNA duplexes (si-F-IRF3-1, si-F-IRF3-2, and si-F-IRF3-3) targeting IRF3, and one siRNA duplex (si-F-IRF7) targeting IRF7 were generated. A nontarget siRNA duplex was used as the negative control. The nontarget or target siRNA duplexes (si-F-IRF3-1, si-F-IRF3-2, si-F-IRF3-3, and si-F-IRF7) were transfected into FRhK-4 cells using transfection reagents, and they were then incubated at 37°C for 6 h with 5% CO2. After 6 h, the medium was removed, and fresh medium was added to each cell, and they were then incubated at 37°C for 48 h with 5% CO2. The transfected FRhK-4 cells were infected with hepatitis A virus (HAV) HM-175/18f (viral titer: 105 PFU/mL) and incubated at 37°C for 3 h with 5% CO2 for HAV propagation. The expression levels of chemokines, including CXCL10 and CCL4, under the regulation of IRF3 and IRF7 in the transfected FRhK-4 cells were measured using quantitative real-time polymerase chain reaction after 3 h of HAV infection. The results indicated that CXCL10 and CCL4 expression levels were decreased in FRhK-4 cells transfected with si-F-IRF3-1, si-F-IRF3-3, or si-F-IRF7 (p < 0.05) compared to those in the negative control. These results indicate that si-F-IRF3-1 and si-F-IRF3-3, and si-F-IRF7 successfully knocked down IRF3 and IRF7 in FRhK-4 cells, respectively and suppressed antiviral chemokines. These siRNAs could be used to suppress antiviral chemokines in FRhK-4 cells.

Quantitative Risk Assessment of Hepatitis a Virus Infection Arising from the Consumption of Fermented Clams in South Korea.

This study estimated the risk of hepatitis A virus (HAV) foodborne illness outbreaks through the consumption of fermented clams in South Korea. HAV prevalence in fermented clams was obtained from the Ministry of Food and Drug Safety Report, 2019. Fermented clam samples (2 g) were inoculated with HAV and stored at -20-25 °C. Based on the HAV titer (determined using plaque assay) in fermented clams according to storage, the Baranyi predictive models provided by Combase were applied to describe the kinetic behavior of HAV in fermented clams. The initial estimated HAV contamination level was -3.7 Log PFU/g. The developed predictive models revealed that, when the temperature increased, the number of HAV plaques decreased. The Beta-Poisson model was chosen for determining the dose-response of HAV, and the simulation revealed that there was a 6.56 × 10-11/person/day chance of contracting HAV foodborne illness by eating fermented clams. However, when only regular consumers of fermented clams were assumed as the population, the probability of HAV foodborne illness increased to 8.11 × 10-8/person/day. These results suggest that, while there is a low likelihood of HAV foodborne illness from consuming fermented clams across the country, regular consumers should be aware of the possibility of foodborne illness.

Lactobacillus fermentum SMFM2017-NK4 Isolated from Kimchi Can Prevent Obesity by Inhibiting Fat Accumulation.

This study evaluated the anti-obesity effects of lactic acid bacteria. Thirty-one lactic acid bacteria were examined in vitro for their ability to inhibit α-glucosidase activity, lipase activity, and 3T3-L1 cell differentiation. Four selected lactic acid bacteria were administered to obese C57BL/6J mice models for 8 weeks. The degree of improvement in obesity was determined by weight gain and serum biochemical analysis. The expression levels of genes (Fas and Cpt-2) related to obesity in the liver were analyzed by quantitative reverse transcription (qRT)-PCR. In addition, antioxidant protein levels (SOD-2, CAT, and GPx-1) in the liver were evaluated. The lactic acid bacteria-treated groups (PPGK1, LFNK3, LPNK2, and LFNK4) showed lower weight increase rate than the control group. The total cholesterol (T-chol), triglyceride (TG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in the blood serum of the LFNK4 group were the lowest among other groups, compared to the control group. The expression levels of lipid metabolism-related genes (Fas and Cpt-2) in the liver of the LFNK4 group were lower in Fas and higher in Cpt-2 than in the control group. The antioxidant protein expression levels (SOD-2, CAT, and GPx-1) in the liver tissue were also higher in the LFNK4 group. These results indicate that L. fermentum SMFM2017-NK4 has anti-obesity effects.