Nitrite plays a major role in inhibiting the growth of foodborne pathogens, including Clostridium botulinum (C. botulinum) that causes botulism, a life-threatening disease. Nitrite serves as a color-fixing agent in processed meat products. However, N-nitroso compounds can be produced from nitrite, which are considered as carcinogens. Thus, consumers desire processed meat products that contain lower concentrations (below conventional concentrations of products) of nitrite or no nitrite at all, although the portion of nitrite intake by processed meat consumption in total nitrite intake is very low. However, lower nitrite levels might expose consumers to risk of botulism poisoning due to C. botulinum or illness caused by other foodborne pathogens. Hence, lower nitrite concentrations in combination with other factors such as low pH, high sodium chloride level, and others have been recommended to decrease the risk of food poisoning. In addition, natural compounds that can inhibit bacterial growth and function as color-fixing agents have been developed to replace nitrite in processed meat products. However, their antibotulinal effects have not been fully clarified. Therefore, to have processed meat products with lower nitrite concentrations, low pH, high sodium chloride concentration, and others should also be applied together. Before using natural compounds as replacement of nitrite, their antibotulinal activities should be examined.

This study aimed to analyze the effect of milk fermented with Lactobacillus curvatus SMFM2016-NK on periodontal diseases and gut health in a rat model. To improve the effect of Lb. curvatus SMFM2016-NK-fermented milk administration for relieving periodontitis, the periodontitis rat models were treated with the following for 4 wk: 10% skim milk (normal), periodontitis + 10% skim milk (negative control), periodontitis + Lactobacillus rhamnosus GG-fermented milk (positive control), and periodontitis + Lb. curvatus SMFM2016-NK-fermented milk (PD+LCFM). Transcriptional analysis of inflammatory cytokines [tumor necrosis factor α (TNF-α), IL-1β, IL-6, and IL-10] was performed via quantitative reverse-transcription PCR. The changes in the oral and gut microbiomes after administering Lb. curvatus SMFM2016-NK-fermented milk were analyzed with metagenomics sequencing using DNA extracted from the oral gingival tissues and feces from the cecum of the rat models. After treatment with Lb. curvatus SMFM2016-NK-fermented milk, the relative gene expression levels of TNFA and IL1B in the gingiva decreased in the PD+LCFM group compared with those in the negative control group. In the oral microbiome, the proportion of the phylum Proteobacteria in the PD+LCFM group was lower than that in the negative control after treatment with Lb. curvatus SMFM2016-NK-fermented milk. For the effect in the gut, the relative gene expression levels of inflammatory cytokines in the colon between the normal and negative control groups were not different; however, the expression levels of TNFA and IL1B in the PD+LCFM and positive control groups, respectively, were lower than those in the negative control group. The composition and diversity of the gut microbiome differed among normal, periodontitis, and Lb. curvatus SMFM2016-NK-fermented milk treatment groups. These results indicate that Lb. curvatus SMFM2016-NK-fermented milk could alleviate periodontal and gut inflammation and change oral and gut microbiota.

Food Science of Animal Resources (Food Sci. Anim. Resour.) is an international, peer-reviewed bimonthly journal publishing original research and reviews on basic and applied aspects of the use of animal resources including the meat, egg, dairy, and edible insect/worm products. Food Sci. Anim. Resour. is published and distributed by the Korean Society for Food Science of Animal Resources.

Dry aging creates a unique taste and flavor in beef; however, the process also causes rancidity, which is harmful to humans. During dry aging, the microbial flora in beef changes continuously; thus, this change can be used as an indicator of rancidity. The objective of this study was to analyze the correlation between microbial flora in beef and rancidity during dry aging. The round of beef (2.5–3 kg) was dry aged under 1.5 ± 1 °C and 82 ± 5% moisture for 17 weeks. The microflora in the dry aged beef was analyzed by pyrosequencing. The volatile basic nitrogen (VBN) and thiobarbituric acid reactive substance (TBARS) values were also measured. Primers were designed to detect and quantify bacteria using real-time polymerase chain reaction (RT-PCR). The VBN and TBARS values in the dry aged beef depreciated from week 11 of aging. The levels of Streptococcus spp., Pantoea spp., and Pseudomonas spp. significantly changed at around week 11. Quantitative RT-PCR showed that the levels of Pantoea spp. and Streptococcus spp. could be used to identify rancidity during dry aging. Thus, among the microbial flora in dry aged beef, Pantoea spp. and Streptococcus spp. can be used to determine the rancidity of dry aged beef.

This study aimed to compare the three strains of Listeria monocytogenes survival in raw milk cheese and pasteurized milk cheese and to suggest the effect of milk microbiota on survival. L. monocytogenes cell counts decreased in all cheese as ripening time increased, and the survival rate was different for the strains of L. monocytogenes. Furthermore, L. monocytogenes survived longer in raw milk cheese than in pasteurized milk cheese. The difference of bacterial survival in each cheese was independent of A_w or the Lactobacillus spp. populations in cheeses; there was no difference in A_w or Lactobacillus spp. populations in all cheeses. The richness of microbiota in raw milk was little higher than in pasteurized milk, and five phyla (Chloroflexi, Cyanobacteria, Deinococcus–Thermus, Lentisphaerae, and Verrucomicrobia) were present only in raw milk. Also, organic acid‐producing bacteria were presented more in pasteurized milk compared with raw milk; thus, the growth of L. monocytogenes was slower in pasteurized milk. In conclusion, differences in the microbial community of milk can affect the growth of L. monocytogenes. Making cheese using raw milk is a risk of L. monocytogenes infection; thus, efforts to prevent growth of L. monocytogenes such as the use of appropriate food additives are required.

Food Science of Animal Resources (Food Sci. Anim. Resour.) is an international, peerreviewed bimonthly journal publishing original research and reviews on basic and applied aspects of the use of animal resources including the meat, egg, and dairy product. Food Sci. Anim. Resour. is published and distributed by the Korean Society for Food Science of Animal Resources.