Differential mechanism between Listeria monocytogenes strains with different virulence contaminating ready-to-eat sausages during the simulated gastrointestinal tract.

Listeria monocytogenes exhibits varying levels of pathogenicity when entering the host through contaminated food. However, little is known regarding the stress response and environmental tolerance mechanism of different virulence strains to host gastrointestinal (GI) stimuli. This study analyzed the differences in the survival and genes of stress responses among two strains of L. monocytogenes 10403S (serotype 1/2a, highly virulent strain) and M7 (serotype 4a, low-virulence strain) during simulated gastrointestinal digestion. The results indicated that L. monocytogenes 10403S showed greater acid and bile salt tolerance than L. monocytogenes M7, with higher survival rates and less cell deformation and cell membrane permeability during the in vitro digestion. KEGG analysis of the transcriptomes indicated that L. monocytogenes 10403S displayed significant activity in amino acid metabolism, such as glutamate and arginine, associated with acid tolerance. Additionally, L. monocytogenes 10403S demonstrated a higher efficacy in promoting activities that preserve bacterial cell membrane integrity and facilitate flagellar protein synthesis. These findings will contribute valuable practical insights into the tolerance distinctions among different virulence strains of L. monocytogenes in the GI environment.

The Application of Ultraviolet Treatment to Prolong the Shelf Life of Chilled Beef.

This study simulated the storage conditions of chilled beef at retail or at home, and the sterilization and preservation effects of short-time ultraviolet irradiation were studied. The conditions of different irradiation distances (6 cm, 9 cm, and 12 cm) and irradiation times (6 s, 10 s, and 14 s) of ultraviolet (UV) sterilization in chilled beef were optimized, so as to maximally reduce the initial bacterial count, but not affect the quality of the chilled beef. Then, the preservation effect on the chilled beef after the optimized UV sterilization treatment during 0 ± 0.2 °C storage was investigated. The results showed that UV irradiation with parameters of 6 cm and 14 s formed the optimal UV sterilization conditions for the chilled beef, maximally reducing the number of microorganisms by 0.8 log CFU/g without affecting lipid oxidation or color change. The 6 cm and 14 s UV sterilization treatment of the chilled beef was able to reduce the initial microbial count, control the bacterial growth, and delay the increase in the TVB-N values during storage. Compared with the control group, the total bacterial count decreased by 0.56-1.51 log CFU/g and the TVB-N value decreased by 0.20-5.02 mg N/100 g in the UV-treated group. It was found that the TBARS value of the UV treatment group increased during late storage; on days 9-15 of storage, the TBARS values of the treatment group were 0.063-0.12 mg MDA/kg higher than those of the control group. However, UV treatment had no adverse impact on the pH, color, or sensory quality of chilled beef. These results prove that UV treatment can effectively reduce the microbial count on the surface of beef and improve its microbial safety, thus maintaining the quality of beef and prolonging its shelf life. This study could provide a theoretical basis for the preservation technology of chilled beef in small-space storage equipment.

Effect of temperature fluctuation during superchilling storage on the microstructure and quality of raw pork.

The effect of different temperature fluctuations on the microstructure and quality of pork loins during superchilling storage was investigated. Based on the dynamic monitoring of ice crystal formation and melting in pork through cryomicroscope, the changes of ice crystals in pork were observed at different temperature points, and there was no obvious phase transition in pork at -3 °C for a short period of time, but the freeze-thaw cycles were obviously found in the samples of -3 ± 3 °C and -3 ± 5 °C groups. Results of microstructure observation showed that temperature fluctuations resulted in muscle fiber fracture and the decrease of water holding capacity of superchilling pork, where stronger temperature fluctuation showed more significant changes. The temperature fluctuation groups exhibited higher thiobarbituric acid reactive substances (TBARS) values after 20 days of storage, and contributed to the reduction of immobilized water and the increase of free water in raw pork, and had more serious drip loss. These indicated that increased temperature fluctuation promoted lipid oxidation and drip loss of pork during storage. This study provided supports to precise temperature control in cold chain logistics of raw meat.

Effect of Different Degrees of Deep Freezing on the Quality of Snowflake Beef during Storage.

In order to elucidate whether deep freezing could maintain the quality of snowflake beef, three different deep freezing temperatures (-18 °C, -40 °C, and -60 °C) were used in order to evaluate the changes in tissue structures, quality characteristics and spoilage indexes, and their comparative effects on the quality of snowflake beef. Compared to samples frozen at -18 °C, those stored at -40 °C and -60 °C took a shorter time to exceed the maximum ice crystallization zone (significantly reduced by 2-6 h). In terms of short-term storage, samples frozen at -40 °C and -60 °C had better tissue structure and lower drip loss rate than those frozen at -18 °C; significant differences between groups in drip loss were observed between -18 °C and -60 °C. Moreover, a better bright red color and lower shear force were maintained at -40 °C and -60 °C, with significant differences in shear force between the -18 °C group and the other two groups on day 60. Although there were significant effects on the inhibition of lipid and protein oxidation at -40 °C and -60 °C; no significant variation was observed between these two groups throughout storage. A similar phenomenon was found in flavor, with 1-pentanol identified as an important potential indicator of flavor change in snowflake beef during storage. This study demonstrated that -40 °C and -60 °C had favorable impacts on the quality maintenance of snowflake beef compared to -18 °C. These findings provide a theoretical basis for effective stability of snowflake beef quality during frozen storage.

TMT-Based Quantitative Proteomic Analysis of Intestinal Organoids Infected by Listeria monocytogenes Strains with Different Virulence.

L. monocytogenes, consisting of 13 serotypes, is an opportunistic food-borne pathogen that causes different host reactions depending on its serotypes. In this study, highly toxic L. monocytogenes 10403s resulted in more severe infections and lower survival rates. Additionally, to investigate the remodeling of the host proteome by strains exhibiting differential toxicity, the cellular protein responses of intestinal organoids were analyzed using tandem mass tag (TMT) labeling and high-performance liquid chromatography−mass spectrometry. The virulent strain 10403s caused 102 up-regulated and 52 down-regulated proteins, while the low virulent strain M7 caused 188 up-regulated and 25 down-regulated proteins. Based on the analysis of gene ontology (GO) and KEGG databases, the expressions of differential proteins in organoids infected by L. monocytogenes 10403s (virulent strain) or M7 (low virulent strain) were involved in regulating essential processes such as the biological metabolism, the energy metabolism, and immune system processes. The results showed that the immune system process, as the primary host defense response to L. monocytogenes, comprised five pathways, including ECM−receptor interaction, the complement and coagulation cascades, HIF-1, ferroptosis, and NOD-like receptor signaling pathways. As for the L. monocytogenes 10403s vs. M7 group, the expression of differential proteins was involved in two pathways: systemic lupus erythematosus and transcriptional mis-regulation in cancer. All in all, these results revealed that L. monocytogenes strains with different toxicity induced similar biological functions and immune responses while having different regulations on differential proteins in the pathway.

Synergistic Effect of Static Magnetic Field and Modified Atmosphere Packaging in Controlling Blown Pack Spoilage in Meatballs.

This study aimed to compare the microbial diversity in meatballs with or without blown pack spoilage (BPS) to determine the cause of BPS and to assess the synergistic effect of static magnetic field (SMF) and modified atmosphere packaging (MAP) to reduce the phenomenon of BPS. Results showed that the BPS group with a 2.26-fold larger volume and packaging containing 71.85% CO2 had Klebsiella spp. (46.05%) and Escherichia spp. (39.96%) as the dominant bacteria, which was different from the spoilage group. The results of isolation and identification of strains from the BPS group and their inoculation test confirmed that Klebsiella pneumoniae was the major strain-inducing BPS in meatballs due to its pack-swelling ability. SMF (5 mT) treatment combined with MAP (40%CO2 + 60%N2), which did not influence the sensory quality of meatballs, had a significant synergistic effect on preventing the increase in pack volume. Compared with the control group, this synergistic treatment effectively delayed bacterial growth, drop in pH, and the increase of TBARS. The findings of this study will provide further guidance for meatball manufacturers to adopt effective strategies to reduce the BPS of meatballs.

Expansion of Intestinal Secretory Cell Population Induced by Listeria monocytogenes Infection: Accompanied With the Inhibition of NOTCH Pathway.

Listeria monocytogenes, as a model organism, is a causative agent of enteric pathogen that causes systemic infection. However, the interaction of L. monocytogenes and small intestinal epithelium has not been fully elucidated yet. In this study, mice and intestinal organoids were chosen as the models to investigate the influence of L. monocytogenes infection on the intestinal secretory cells and its differentiation-related pathways. Results confirmed the phenomenon of intestinal damage that L. monocytogenes infection could lead to villi damage in mice, which was accompanied by the increase of TNF-α production in jejunum as well as lipopolysaccharide (LPS) secretion in serum. Moreover, it was demonstrated that L. monocytogenes infection increased the number of goblet and Paneth cells in mice and intestinal organoids and upregulated the expression of Muc2 and Lyz. Furthermore, L. monocytogenes decreased the relative expression of Notch pathway-related genes (Jag1, Dll4, Notch1, and Hes1) while upregulating the relative expression of Math1 gene in mice and intestinal organoids. This indicated that L. monocytogenes infection caused the inhibition of Notch pathway, which may be the reason for the increased number of goblet and Paneth cells in the intestine. Collectively, these results are expected to provide more information on the mechanism of L. monocytogenes infection in the intestine.

Involvement of CCN1 Protein and TLR2/4 Signaling Pathways in Intestinal Epithelial Cells Response to Listeria monocytogenes.

CCN1 is well studied in terms of its functions in injury repair, cell adhesion survival and apoptosis, bacterial clearance and mediation of inflammation-related pathways, such as the TLR2/4 pathways. However, the role of CCN1 protein and its interaction with TLR2/4 pathways in intestinal epithelial cells was not elucidated after Listeria monocytogenes infection. The results of this study confirm that L. monocytogenes infection induced intestinal inflammation and increased the protein expression of CCN1, TLR2, TLR4 and p38, which followed a similar tendency in the expression of genes related to the TLR2/4 pathways. In addition, organoids infected by L. monocytogenes showed a significant increase in the expression of CCN1 and the activation of TLR2/4 pathways. Furthermore, pre-treatment with CCN1 protein to organoids infected by L. monocytogenes could increase the related genes of TLR2/4 pathways and up-regulate the expression of TNF, and increase the count of pathogens in organoids, which indicates that the interaction between the CCN1 protein and TLR2/4 signaling pathways in intestinal epithelial cells occurred after L. monocytogenes infection. This study will provide a novel insight of the role of CCN1 protein after L. monocytogenes infection in the intestine.

Investigation of the effect of pork compositions on freezing points in different pork cuts by measuring thermal properties and water mobility and distribution.

This work was to compare the difference of freezing point in the four pork cuts (chuck roll, picnic shoulder, loin, and topside) and evaluate the effect of pork compositions on the freezing points. Loin exhibited lower freezing points and accompanied by higher content of unfreezable water, lower relaxation times, and higher proportions of bound water, compared with other pork cuts. Low freezing points of pork may be attributed to high sarcoplasmic protein solubility, due to high sarcoplasmic protein solubility related to increase of bound water proportion and decrease of NMR T2 relaxometry. In addition, correlation analysis revealed that sarcoplasmic protein solubility and ash content were negatively related to the freezing point, which was verified by a quadratic polynomial correlation between the sarcoplasmic protein solubility and the freezing point in vitro. These results could help to better understand the freezing point of pork and provide more theories for improving superchilled storage.

Assessment of quality characteristics and bacterial community of modified atmosphere packaged chilled pork loins using 16S rRNA amplicon sequencing analysis.

Modified atmosphere packaging (MAP) is widely applied in packaging meat and meat products. While most studies had employed culture-dependent microbiological analyses or polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), the recent application of high-throughput sequencing (HTS) has been effective and reliable in detecting the microbial consortium associated with food spoilage. Since MAP application is limited in China, applying HTS in assessing the microbial consortium of meat and meat products in the country becomes imperative. In this study, quality indexes and bacterial enumeration often used as spoilage indicators were employed to assess MAP fresh pork under chilled (4 °C) storage for 21 d. The results indicated that 70%O2/30%CO2 (Group A) retained more redness (a*) content, while 70%N2/30%CO2 (Group B) markedly reduced spoilage indicators compared to the control group. Notably, high-throughput sequencing indicated that Group B and 20%O2/60%N2/20%CO2 (Group C) inhibited the growth of abundant spoilers, Pseudomonas spp. and Brochothrix spp. Thus, MAP (Group B and C) has promising potential in inhibiting predominant meat spoilers during chilled storage. This study provides valuable information to food industries on the potential application of MAP to control meat spoilage in Chinese markets.

Effects of gellan gum and inulin on mixed-gel properties and molecular structure of gelatin.

Gellan gum (GG) is often added to gelatin (GL) to improve the gel property. GG-based or inulin (IL)-based hydrogels were developed. Rigid and brittle gels or smooth and delicate gels were prepared with GG and IL, respectively. This study aimed to explore the properties and interaction mechanisms of the mixed-gel system containing GL, GG, and IL, in which different ratios of GG-IL (0.4%) (10:0, 8:2, 6:4, 5:5, 4:6, 2:8, and 0:10) were added to GL (6%). Texture profiles, rheological properties, water mobility, intermolecular forces, circular dichroism (CD) spectra, and microstructures were analyzed. The results showed that addition of GG-IL could improve the hardness, chewiness, and cohesiveness of mixed-gel, besides maintaining appropriate springiness. Water mobility of the mixed-gel decreased while viscoelasticity increased upon the addition GG. At GG:IL = 2:8, the melting temperature of mixed-gel was far higher than that of GL gel itself. The GL-GG-IL gel showed decrease in nonspecific bonding and increase in hydrogen bonding compared with the GL gel. CD spectra indicated the promotion of GL unfolding by GG, hence suggesting the binding of GG to GL; binding ability was better at GG:IL >5:5. Cryo-SEM provided evidence for the formation of cross-linked network within GL-GG-IL. Overall, we concluded that addition of GG-IL to GL system would be most suitable for improving the properties of mixed-gel. This finding may be potentially applicable in the further development of gel food products, such as meat jellies and gummy jellies.

Effect of Listeria monocytogenes on intestinal stem cells in the co-culture model of small intestinal organoids.

Listeria monocytogenes is a foodborne pathogen that causes systemic infections by crossing the intestinal barrier. However, in vitro analysis of the interaction of L. monocytogenes and small intestinal epithelium has yet to be fully elucidated. To study host responses from intestinal epithelium during L. monocytogenes infection, we used the co-culture model of small intestinal organoids and L. monocytogenes. Results showed that L. monocytogenes mediated damage to intestinal epithelium, especially intestinal stem cells. L. monocytogenes was found to reduce budding rate and increase mortality of organoids. Moreover, it affected the proliferation of epithelial cells and numbers of secretory cells. In addition, it was demonstrated that L. monocytogenes stimulated a reduction in the number of Lgr5+ stem cells. Furthermore, L. monocytogenes affected the expression of Hes1, Math1 and Sox9 to interfere with the differentiation of intestinal stem cells. Collectively, our findings reveal the effects of L. monocytogenes infection on intestinal stem cells and demonstrate that small intestinal organoid is a suitable experimental model for studying intestinal epithelium-pathogen interactions.

The effects of thermal treatment on the bacterial community and quality characteristics of meatballs during storage.

Thermal treatment is a widely applied food processing technology in the meat industry due to its convenience. However, the interpretation of the changes in the bacterial community and quality properties in the thermal processed meat products have not been well established. Therefore, the effects of thermal treatment on the quality characteristics and bacterial communities in meatballs during storage at 4°C were investigated, which will provide a more comprehensive understanding of the influence of thermal treatment on the meat quality. Thermal treatment (121°C, 15 min) decreased the initial total viable bacterial counts by 2.1 log CFU/g and the diversity of the initial bacterial communities in meatballs. Compared with the thermal treatment group, a significantly more rapidly increasing trend of total volatile basic nitrogen and a decreasing trend of pH were observed in the control group. At the end of storage, the bacterial community was dominated by Streptococcus, Acinetobacter and Pseudomonas in the thermal treatment meatballs, whereas Pseudomonas, Pantoea, and Serratia. dominated the bacterial community of the control group. Besides, the predicted metabolic pathways revealed high levels of carbohydrate, amino acid, and lipid metabolism in the control group. This finding could contribute to a deep understanding of the influence of thermal treatment on the meat quality. Moreover, these results could provide a theoretical foundation for the development of alternative and novel nonthermal processing technologies for use in the meat industry.

Principal component analysis of MALDI-TOF MS of whole-cell foodborne pathogenic bacteria.

The rapid and accurate identification of foodborne pathogenic bacteria is of great importance for human health. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) can be used to rapidly and sensitively identify microorganisms but is limited by the expensive protein databases available. In this study, we established a whole-cell method for the identification of foodborne pathogenic bacteria, using MALDI-TOF MS and principal component analysis (PCA), which did not use protein extractions or expensive protein databases. Thirty strains comprising six common foodborne pathogenic bacteria, namely, Shigella flexneri, Escherichia coli, Staphylococcus aureus, Salmonella enteritidis, Pseudomonas aeruginosa, and Listeria monocytogenes were analyzed using MALDI-TOF MS. The culture time, matrix, and spotting method were optimized based on peak intensity and deviation. A PCA was performed to analyze the mass spectrometry results of six samples and proved capable of identifying significant changes in those samples. It was found that directly applying MALDI-TOF MS analysis to whole-cell bacteria, without protein extraction, exhibited rich peak contents and a high level of reproducibility. MALDI-TOF MS combined with PCA is a promising method of rapidly identifying pathogens in food products.

High-Salt Diet Has a Certain Impact on Protein Digestion and Gut Microbiota: A Sequencing and Proteome Combined Study.

High-salt diet has been considered to cause health problems, but it is still less known how high-salt diet affects gut microbiota, protein digestion, and passage in the digestive tract. In this study, C57BL/6J mice were fed low- or high-salt diets (0.25 vs. 3.15% NaCl) for 8 weeks, and then gut contents and feces were collected. Fecal microbiota was identified by sequencing the V4 region of 16S ribosomal RNA gene. Proteins and digested products of duodenal, jejunal, cecal, and colonic contents were identified by LC-MS-MS. The results indicated that the high-salt diet increased Firmicutes/Bacteroidetes ratio, the abundances of genera Lachnospiraceae and Ruminococcus (P < 0.05), but decreased the abundance of Lactobacillus (P < 0.05). LC-MS-MS revealed a dynamic change of proteins from the diet, host, and gut microbiota alongside the digestive tract. For dietary proteins, high-salt diet seemed not influence its protein digestion and absorption. For host proteins, 20 proteins of lower abundance were identified in the high-salt diet group in duodenal contents, which were involved in digestive enzymes and pancreatic secretion. However, no significant differentially expressed proteins were detected in jejunal, cecal, and colonic contents. For bacterial proteins, proteins secreted by gut microbiota were involved in energy metabolism, sodium transport, and protein folding. Five proteins (cytidylate kinase, trigger factor, 6-phosphogluconate dehydrogenase, transporter, and undecaprenyl-diphosphatase) had a higher abundance in the high-salt diet group than those in the low-salt group, while two proteins (acetylglutamate kinase and PBSX phage manganese-containing catalase) were over-expressed in the low-salt diet group than in the high-salt group. Consequently, high-salt diet may alter the composition of gut microbiota and has a certain impact on protein digestion.

Beef, Chicken, and Soy Proteins in Diets Induce Different Gut Microbiota and Metabolites in Rats.

Previous studies have paid much attention to the associations between high intake of meat and host health. Our previous study showed that the intake of meat proteins can maintain a more balanced composition of gut bacteria as compared to soy protein diet. However, the associations between dietary protein source, gut bacteria, and host health were still unclear. In this study, we collected colonic contents from the growing rats fed with casein, beef, chicken or soy proteins for 90 days, and analyzed the compositions of gut microbiota and metabolites. Compared to the casein group (control), the chicken protein group showed the highest relative abundance of Lactobacillus and the highest levels of organic acids, including lactate, which can in turn promote the growth of Lactobacillus. The soy protein group had the highest relative abundance of Ruminococcus but the lowest relative abundance of Lactobacillus. Long-term intake of soy protein led to the up-regulation of transcription factor CD14 receptor and lipopolysaccharide-binding protein (LBP) in liver, an indicator for elevated bacterial endotoxins. In addition, the intake of soy protein also increased the levels of glutathione S-transferases in liver, which implicates elevated defense and stress responses. These results confirmed that meat protein intake may maintain a more balanced composition of gut bacteria and reduce the antigen load and inflammatory response from gut bacteria to the host.

Comparison of anti-pathogenic activities of the human and bovine milk N-glycome: Fucosylation is a key factor.

Health differences between breast- and formula-fed infants have long been apparent despite great efforts in improving the function of baby formula by adjusting the levels of various milk nutritional components. However, the N-glycome, a type of oligosaccharide decorating a diverse range of proteins, has not been extensively studied in milk regarding its biological function. In this study, the anti-pathogenic function of the enzymatically released human and bovine milk N-glycome against 5 food-borne pathogens was investigated. The human milk N-glycome showed significantly higher activity than bovine milk. After enzymatic defucosylation of human and bovine N-glycan pool, UHPLC peak shifts were observed in both suggesting heavy fucosylation of samples. Furthermore, the anti-pathogenic activity of the defulosylated N-glycome decreased significantly, and the significance of functional difference between the two almost disappeared. This result indicates the essential role of fucosylation for the anti-pathogenic function of the milk N-glycome, especially in human milk.

Microbial analysis of MAP pot-stewed duck wings under different conditions during 15 °C storage.

This study was to investigate the changes of microbial community and counts of MAP pot-stewed duck wing (PSDW) under different packaging films and spices ratio during 15 °C storage, using the traditional bacterial cultivation and PCR-DGGE. Results of microbial counting showed that the shelf-life of PDSW during 15 °C storage for recommendation was within six days, and the packaging films and spices ratio didn't affect the change of microbial numbers in PSDW during storage. PCR-DGGE analysis revealed that Staphylococcus equorum, Weissella sp., Leuconostoc mesenteroides became the dominating bacteria of PSDW at the end of storage, and high barrier cover film, general barrier base film and spice ratio 1:1, had a better inhibition effect on bacteria in PSDW products, which could be used as the condition for PSDW storage. This study will help PSDW processing enterprises visualize the biodiversity of PSDW during storage, and choose the best condition for the subsequent processing.

Evaluation of the spoilage potential of bacteria isolated from chilled chicken in vitro and in situ.

Microorganisms play an important role in the spoilage of chilled chicken. In this study, a total of 53 isolates, belonging to 7 species of 3 genera, were isolated using a selective medium based on the capacity to spoil chicken juice. Four isolates, namely Aeromonas salmonicida 35, Pseudomonas fluorescens H5, Pseudomonas fragi H8 and Serratia liquefaciens 17, were further characterized to assess their proteolytic activities in vitro using meat protein extracts and to evaluate their spoilage potential in situ. The in vitro studies showed that A. salmonicida 35 displayed the strongest proteolytic activity against both sarcoplasmic and myofibrillar proteins. However, the major spoilage isolate in situ was P. fragi H8, which exhibited a fast growth rate, slime formation and increased pH and total volatile basic nitrogen (TVBN) on chicken breast fillets. The relative amounts of volatile organic compounds (VOCs) originating from the microorganisms, including alcohols, aldehydes, ketones and several sulfur compounds, increased during storage. In sum, this study demonstrated the characteristics of 4 potential spoilage bacteria on chilled yellow-feather chicken and provides a simple and convenient method to assess spoilage bacteria during quality management.

Antibacterial Activity and Mechanism of Action of Black Pepper Essential Oil on Meat-Borne Escherichia coli.

The aim of this study was to investigate the antibacterial activity of black pepper essential oil (BPEO) on Escherichia coli, further evaluate the potential mechanism of action. Results showed that the minimum inhibition concentration (MIC) of BPEO was 1.0 µL/mL. The diameter of inhibition zone values were with range from 17.12 to 26.13 mm. 2 × MIC treatments had lower membrane potential and shorter kill-time than 1 × MIC, while control had the highest values. E. coli treated with BPEO became deformed, pitted, shriveled, adhesive, and broken. 2 × MIC exhibited the greatest electric conductivity at 1, 3, 5, 7, 9, 11, and 13 h, leaked DNA materials at 4, 8, 12, 16, 20, 24, and 28 h, proteins at 4, 6, 8, 10, 12, 14, and 16 h, potassium ion at 0, 0.5, 1, 1.5, and 2 h, phosphate ion at 0.5, 1, 1.5, and 2 h and ATP (P < 0.05); 1 × MIC had higher values than control. BPEO led to the leakage, disorder and death by breaking cell membrane. This study suggested that the BPEO has potential as the natural antibacterial agent in meat industry.