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Applied Microbiology and Biotechnology Jun 2024Bacteriocins have the potential to effectively improve food-borne infections or gastrointestinal diseases and hold promise as viable alternatives to antibiotics. This...
Bacteriocins have the potential to effectively improve food-borne infections or gastrointestinal diseases and hold promise as viable alternatives to antibiotics. This study aimed to explore the antibacterial activity of three bacteriocins (nisin, enterocin Gr17, and plantaricin RX-8) and their ability to attenuate intestinal barrier dysfunction and inflammatory responses induced by Listeria monocytogenes, respectively. Bacteriocins have shown excellent antibacterial activity against L. monocytogenes without causing any cytotoxicity. Bacteriocins inhibited the adhesion and invasion of L. monocytogenes on Caco-2 cells, lactate dehydrogenase (LDH), trans-epithelial electrical resistance (TEER), and cell migration showed that bacteriocin improved the permeability of Caco-2 cells. These results were attributed to the promotion of tight junction proteins (TJP) assembly, specifically zonula occludens-1 (ZO-1), occludin, and claudin-1. Furthermore, bacteriocins could alleviate inflammation by inhibiting the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathways and reducing the secretion of interleukin-6 (IL-6), interleukin-1 β (IL-1β) and tumor necrosis factor α (TNF-α). Among three bacteriocins, plantaricin RX-8 showed the best antibacterial activity against L. monocytogenes and the most pronounced protective effect on the intestinal barrier due to its unique structure. Based on our findings, we hypothesized that bacteriocins may inhibit the adhesion and invasion of L. monocytogenes by competing adhesion sites. Moreover, they may further enhance intestinal barrier function by inhibiting the expression of L. monocytogenes virulence factors, increasing the expression of TJP and decreasing the secretion of inflammatory factors. Therefore, bacteriocins will hopefully be an effective alternative to antibiotics, and this study provides valuable insights into food safety concerns. KEY POINTS: • Bacteriocins show excellent antibacterial activity against L. monocytogenes • Bacteriocins improve intestinal barrier damage and inflammatory response • Plantaricin RX-8 has the best protective effect on Caco-2 cells damage.
Topics: Listeria monocytogenes; Bacteriocins; Humans; Caco-2 Cells; Anti-Bacterial Agents; Inflammation; NF-kappa B; Bacterial Adhesion; Tight Junction Proteins; Cytokines; Listeriosis; Cell Movement
PubMed: 38896287
DOI: 10.1007/s00253-024-13228-w -
Environmental persistence of Listeria monocytogenes and its implications in dairy processing plants.Comprehensive Reviews in Food Science... Nov 2023Listeriosis, an invasive illness with a fatality rate between 20% and 30%, is caused by the ubiquitous bacterium Listeria monocytogenes. Human listeriosis has long been... (Review)
Review
Listeriosis, an invasive illness with a fatality rate between 20% and 30%, is caused by the ubiquitous bacterium Listeria monocytogenes. Human listeriosis has long been associated with foods. This is because the ubiquitous nature of the bacteria renders it a common food contaminant, posing a significant risk to the food processing sector. Although several sophisticated stress coping mechanisms have been identified as significant contributing factors toward the pathogen's persistence, a complete understanding of the mechanisms underlying persistence across various strains remains limited. Moreover, aside from genetic aspects that promote the ability to cope with stress, various environmental factors that exist in food manufacturing plants could also contribute to the persistence of the pathogen. The objective of this review is to provide insight into the challenges faced by the dairy industry because of the pathogens' environmental persistence. Additionally, it also aims to emphasize the diverse adaptation and response mechanisms utilized by L. monocytogenes in food manufacturing plants to evade environmental stressors. The persistence of L. monocytogenes in the food processing environment poses a serious threat to food safety and public health. The emergence of areas with high levels of L. monocytogenes contamination could facilitate Listeria transmission through aerosols, potentially leading to the recontamination of food, particularly from floors and drains, when sanitation is implemented alongside product manufacturing. Hence, to produce safe dairy products and reduce the frequency of outbreaks of listeriosis, it is crucial to understand the factors that contribute to the persistence of this pathogen and to implement efficient control strategies.
Topics: Humans; Listeria monocytogenes; Food Microbiology; Food Contamination; Listeriosis; Public Health
PubMed: 37680027
DOI: 10.1111/1541-4337.13234 -
Food Science and Technology... Dec 2023This study aimed to evaluate the behavior of during the manufacture and storage of artisanal kefir. A five-strain cocktail of was introduced (at 3.0 log CFU/mL) into...
This study aimed to evaluate the behavior of during the manufacture and storage of artisanal kefir. A five-strain cocktail of was introduced (at 3.0 log CFU/mL) into UHT milk as a pre-fermentation contaminant. The growth of lactic acid bacteria and yeasts was monitored during the 24-h fermentation period of milk with two types of kefir grains at 20 °C and the subsequent storage of kefir under adequate (4 °C) and inadequate (10 °C) refrigerated-storage conditions. grew into much higher cell densities (5.3-5.8 log CFU/mL) by the end of the fermentation period, but the final (24-h) counts were substantially lower than those obtained in the corresponding control trials with unfermented milk (7.2 log CFU/mL). The growth rate of during fermentation differed depending on the type of kefir grain used. During the subsequent 11-day storage of the kefir filtrates at 4 °C or 10 °C, the behavior of varied from no growth to further population increases (of up to 1.1 log CFU/mL), depending on the storage temperature, but also depending on the type of kefir grain and the grain surface-to-weight ratio that had been used to ferment the milk. This study highlights the need for strict adherence to good hygiene practices during artisanal kefir making and shows that can sustain considerable growth during milk fermentation and further grow during the subsequent cold storage of kefir, particularly under inadequate refrigerated storage conditions.
Topics: Animals; Kefir; Listeria monocytogenes; Milk; Food Microbiology; Temperature; Colony Count, Microbial
PubMed: 35903903
DOI: 10.1177/10820132221117462 -
Journal of Food Protection Oct 2023Imported mangoes have been linked to outbreaks of salmonellosis in the USA. The purpose of this research was to evaluate the persistence and growth kinetics of...
Imported mangoes have been linked to outbreaks of salmonellosis in the USA. The purpose of this research was to evaluate the persistence and growth kinetics of Salmonella and Listeria monocytogenes on the intact surface of whole 'Ataulfo', 'Kent', and 'Tommy Atkins' mangoes stored at three different temperatures. L. monocytogenes was also evaluated on fresh-cut 'Tommy Atkins' mangoes stored at 4, 12, 20 ± 2°C. Whole mangoes were spot inoculated with rifampicin-resistant pathogen cocktails (6 log CFU/mango) onto the midsection of whole fruit (n = 6). Fruit was stored at 12, 20, or 30 ± 2°C and sampled for up to 28 days. The specific growth rates derived from DMFit models as a function of time were used to develop secondary models. On 'Kent' mangoes, Salmonella had a population increase from 0.3 to 1.1 log CFU/mango with a linear growth rate of ∼0.004, 0.01, and 0.06 log CFU/mango/h at 12, 20, and 30°C, respectively. At 20 and 30°C, Salmonella growth rates were significantly higher than 12°C (P < 0.05). No clear Salmonella growth trend was observed; populations decreased up to 1.6 log CFU/mango on 'Tommy Atkins' and 'Ataulfo' at 12°C. Populations of L. monocytogenes on whole and fresh-cut mangoes declined regardless of temperature and storage period. Food safety during storage should be the top priority for fresh-cut tropical fruit processors.
Topics: Food Microbiology; Listeria monocytogenes; Mangifera; Colony Count, Microbial; Salmonella; Temperature; Food Handling
PubMed: 37634809
DOI: 10.1016/j.jfp.2023.100151 -
Journal of Food Protection Oct 2023This study aimed to determine the persistence of Salmonella Javiana, Listeria monocytogenes, and Listeria innocua in nonsterile, hydroponic nutrient solution (NS) at 15,...
This study aimed to determine the persistence of Salmonella Javiana, Listeria monocytogenes, and Listeria innocua in nonsterile, hydroponic nutrient solution (NS) at 15, 25, 30, and 37°C over a 21-day period to mimic time from seedling to mature lettuce. Bacteria were inoculated in modified Hoagland's NS at 10 CFU/mL and maintained at 15, 25, 30, and 37°C. Samples were collected at various time points, and bacteria were quantified. A mixed model was used to determine the effect of bacteria type, time (day), and temperature on bacteria concentration (log CFU/mL). The least-squares means were calculated to compare the mean log CFU/mL, and the mean values were compared with Tukey-Kramer honest significant difference test with a significance level of P = 0.05. Statistical analysis indicated that a 3-way interaction effect between temperature, time, and bacteria type had a significant impact on bacterial persistence in NS (P < 0.0001). At all temperatures, S. Javiana persisted in NS throughout the 21-day study period, compared to L. innocua and L. monocytogenes where persistence was limited to between 1 and 14 days. Similarly, decimal reduction values (D-values) of S. Javiana indicated longer persistence in NS than L. innocua and L. monocytogenes at most temperatures. For instance, at 15°C and 25°C, D-values for S. Javiana were estimated at 82 and 26 d, respectively, compared to D-values of 3.6 and ∼3 d for L. monocytogenes. Data indicate that the temperature of NS has a differential effect on the persistence of S. Javiana and Listeria spp. This study furthers the understanding of potential food safety risks associated with hydroponic systems and will contribute to the refinement of further studies to aid in the development of operation-specific risk profiles.
Topics: Listeria monocytogenes; Salmonella enterica; Hydroponics; Colony Count, Microbial; Food Microbiology; Listeria; Temperature
PubMed: 37640157
DOI: 10.1016/j.jfp.2023.100154 -
Journal of Medical Microbiology Mar 2024Listeriosis is a foodborne infection in humans caused by Consumption of contaminated food can lead to severe infection in vulnerable patients, that can be fatal....
Listeriosis is a foodborne infection in humans caused by Consumption of contaminated food can lead to severe infection in vulnerable patients, that can be fatal. Clinical manifestations include sepsis and meningitis, and in pregnancy-associated infection, miscarriage and stillbirth. Diagnosis is confirmed by culture and identification of the pathogen from blood, cerebrospinal fluid, vaginal swab, placenta or amniotic fluid. Treatment regimens recommend amoxicillin, ampicillin or an aminoglycoside. Virulence factors mediate bacterial adhesion and invasion of gut epithelial cells. Other factors mediate biofilm formation and tolerance to low temperatures and high salt concentrations facilitating persistence and survival in the environment.
Topics: Pregnancy; Female; Humans; Listeria monocytogenes; Listeriosis; Ampicillin; Pregnancy Complications, Infectious; Anti-Bacterial Agents; Food Microbiology
PubMed: 38506266
DOI: 10.1099/jmm.0.001800 -
Food Research International (Ottawa,... Mar 2024Thermal processing is a widely used method to ensure the microbiological safety of milk. Predictive microbiology plays a crucial role in quantifying microbial growth and...
Thermal processing is a widely used method to ensure the microbiological safety of milk. Predictive microbiology plays a crucial role in quantifying microbial growth and decline, providing valuable guidance on the design and optimization of food processing operations. This study aimed to investigate the thermal inactivation kinetics of Listeria monocytogenes in milk under both isothermal and dynamic conditions. The thermal inactivation of L. monocytogenes was conducted under isothermal and non-isothermal conditions in sterilized and pasteurized milk, with and without background microbiota, respectively. Furthermore, a secondary model was developed between the shoulder effect and temperature, which was then integrated into the dynamic model. The results showed that L. monocytogenes grown in Tryptic Soy Yeast Extract Broth (TSBYE) prior to thermal inactivation exhibited higher heat resistance compared to cells grown in sterilized milk at isothermal temperatures of 60.0, 62.5, and 65℃. Moreover, the presence of background microbiota in milk significantly enhanced the heat resistance of L. monocytogenes, as evidenced by the increased D-values from 1.13 min to 2.34 min, from 0.46 min to 0.53 min, and from 0.25 min to 0.34 min at 60.0, 62.5, and 65 °C, respectively, regardless of whether the background microbiota was inactivated after co-growth or co-inactivated with L. monocytogenes. For non-isothermal inactivation, the one-step dynamic model based on the log-linear with shoulder model effectively described the microbial inactivation curve and exhibited satisfactory model performance. The model developed contributes to improved risk assessment, enabling dairy processors to optimize thermal treatment and ensure microbiological safety.
Topics: Animals; Food Microbiology; Listeria monocytogenes; Milk; Colony Count, Microbial; Hot Temperature
PubMed: 38342535
DOI: 10.1016/j.foodres.2024.114010 -
Food Science and Biotechnology Oct 2023is a critical foodborne pathogen that causes listeriosis and threatens public health. This pathogenic microorganism forms a transmission cycle in nature, food industry,... (Review)
Review
is a critical foodborne pathogen that causes listeriosis and threatens public health. This pathogenic microorganism forms a transmission cycle in nature, food industry, and humans, expanding the areas of contamination among them and influencing food safety. forms biofilms to protect itself and promotes survival through stress responses to the various stresses (e.g., temperature, pH, and antimicrobial agents) that may be inflicted during food processing. Biofilms and mechanisms of resistance to hostile external or general stresses allow to survive despite a variety of efforts to ensure food safety. The current review article focuses on biofilm formation, resistance mechanisms through biofilms, and external specific or general stress responses of to help understand the unexpected survival rates of this bacterium; it also proposes the use of obstacle technology to effectively cope with it in the food industry.
PubMed: 37780599
DOI: 10.1007/s10068-023-01427-6 -
Food Microbiology Sep 2024Listeria monocytogenes presents significant risk to human health due to its high resistance and capacity to form toxin-producing biofilms that contaminate food. The...
Listeria monocytogenes presents significant risk to human health due to its high resistance and capacity to form toxin-producing biofilms that contaminate food. The objective of this study was to assess the inhibitory effect of citronella aldehyde (CIT) on L. monocytogenes and investigate the underlying mechanism of inhibition. The results indicated that the minimum inhibitory concentration (MIC) and Minimum sterilisation concentration (MBC) of CIT against L. monocytogenes was 2 μL/mL. At this concentration, CIT was able to effectively suppress biofilm formation and reduce metabolic activity. Crystalline violet staining and MTT reaction demonstrated that CIT was able to inhibit biofilm formation and reduce bacterial cell activity. Furthermore, the motility assessment assay revealed that CIT inhibited bacterial swarming and swimming. Scanning electron microscopy (SEM) and laser confocal microscopy (LSCM) observations revealed that CIT had a significant detrimental effect on L. monocytogenes cell structure and biofilm integrity. LSCM also observed that nucleic acids of L. monocytogenes were damaged in the CIT-treated group, along with an increase in bacterial extracellular nucleic acid leakage. The proteomic results also confirmed the ability of CIT to affect the expression of proteins related to processes including metabolism, DNA replication and repair, transcription and biofilm formation in L. monocytogenes. Consistent with the proteomics results are ATPase activity and ATP content of L. monocytogenes were significantly reduced following treatment with various concentrations of CIT. Notably, CIT showed good inhibitory activity against L. monocytogenes on cheese via fumigation at 4 °C.This study establishes a foundation for the potential application of CIT in food safety control.
Topics: Listeria monocytogenes; Cheese; Biofilms; Microbial Sensitivity Tests; Anti-Bacterial Agents; Food Preservation; Food Microbiology; Bacterial Proteins; Aldehydes; Plant Extracts; Acyclic Monoterpenes
PubMed: 38839218
DOI: 10.1016/j.fm.2024.104550 -
Frontiers in Immunology 2023Cancer receives enduring international attention due to its extremely high morbidity and mortality. Immunotherapy, which is generally expected to overcome the limits of... (Review)
Review
Cancer receives enduring international attention due to its extremely high morbidity and mortality. Immunotherapy, which is generally expected to overcome the limits of traditional treatments, serves as a promising direction for patients with recurrent or metastatic malignancies. Bacteria-based vectors such as take advantage of their unique characteristics, including preferential infection of host antigen presenting cells, intracellular growth within immune cells, and intercellular dissemination, to further improve the efficacy and minimize off-target effects of tailed immune treatments. can reshape the tumor microenvironment to bolster the anti-tumor effects both through the enhancement of T cells activity and a decrease in the frequency and population of immunosuppressive cells. Modified has been employed as a tool to elicit immune responses against different tumor cells. Currently, vaccine alone is insufficient to treat all patients effectively, which can be addressed if combined with other treatments, such as immune checkpoint inhibitors, reactivated adoptive cell therapy, and radiotherapy. This review summarizes the recent advances in the molecular mechanisms underlying the involvement of vaccine in anti-tumor immunity, and discusses the most concerned issues for future research.
Topics: Humans; Listeria monocytogenes; Neoplasms; Immunotherapy; T-Lymphocytes; Vaccines; Tumor Microenvironment
PubMed: 37868979
DOI: 10.3389/fimmu.2023.1278011