Antifungal effect of organic acids from lactic acid bacteria on Penicillium nordicum

Molecular identification and management of mycotoxigenic fungi in stored corn Grains

Mycotoxin-producing molds which considered as common maize grains contaminants are the genera Fusarium, Aspergillus and Penicillium. There are natural and safe ways to protect grains from mold contamination as the use of essential oils and chemical treatments. A total number of 25 samples were used to study the natural frequency in five governorates in Egypt, Molecular identification indicated that the most frequent fungi were Fusarium verticillioides, Aspergillus niger, Talaromyces verruculosus, Aspergillus flavus and Aspergillus terreus. The in vitro studies have been done to determine mycelial growth and spore germination inhibition of the two A. flavus; isolated and reference isolates. Thyme and acetic acid were tested in direct contact assay to study their effects on mycelial growth. Treatments showed significant impact on mycelial growth and spore germination inhibition of both A. flavus isolates. In the postharvest application treatments: as vapour and carrier contact assay, Thyme and Acetic acid were tested to determine their influence on growth and aflatoxin production in A. flavus isolates by liquid chromatography–electrospray ionization–tandem mass spectrometry (LC–ESI–MS/MS). Results indicated that both treatments were effective in inhibition of aflatoxin production in both vapour and carrier assays as they succeeded in reducing AFB1 while they inhibited completely the production of AFB2. The extent of the inhibition of aflatoxin production was dependent on the concentration and storage duration of treatments applied.

Microbial aromatic amino acid metabolism is modifiable in fermented food matrices to promote bioactivity

Ingestion of fermented foods impacts human immune function, yet the bioactive food components underlying these effects are not understood. Here, we interrogated whether fermented food bioactivity relates to microbial metabolites derived from aromatic amino acids, termed aryl-lactates. Using targeted metabolomics, we established the presence of aryl-lactates in commercially available fermented foods. After pinpointing fermented food-associated lactic acid bacteria that produce high levels of aryl-lactates, we identified fermentation conditions to increase aryl-lactate production in food matrices up to 5 × 103 fold vs. standard fermentation conditions. Using ex vivo reporter assays, we found that food matrix conditions optimized for aryl-lactate production exhibited enhanced agonist activity for the human aryl-hydrocarbon receptor (AhR) as compared to standard fermentation conditions and commercial products. Reduced microbial-induced AhR activity has emerged as a hallmark of many chronic inflammatory diseases, thus we envision strategies to enhance AhR bioactivity of fermented foods to be leveraged to improve human health.

Anti-fungal effects of lactic acid bacteria from pickles on the growth and sterigmatocystin production of Aspergillus versicolor

Sterigmatocystin (STC) is an emerging mycotoxin that poses a significant threat to the food security of cereal crops. To mitigate STC contamination in maize, this study employed selected lactic acid bacteria as biocontrol agents against Aspergillus versicolor, evaluating their biocontrol potential and analyzing the underlying mechanisms. Lactiplantibacillus plantarum HJ10, isolated from pickle, exhibited substantial in vitro antifungal activity and passed safety assessments, including antibiotic resistance and hemolysis tests. In vivo experiments demonstrated that L. plantarum HJ10 significantly reduced the contents of A. versicolor and STC in maize (both >84 %). The impact of heat, enzymes, alkali, and other treatments on the antifungal activity of cell-free supernatant (CFS) was investigated. Integrated ultra-high-performance liquid chromatography (UPLC) and gas chromatography-mass spectrometry (GC-MS) analysis revealed that lactic acid, acetic acid, and formic acid are the key substances responsible for the in vitro antifungal activity of L. plantarum HJ10. These metabolites induced mold apoptosis by disrupting cell wall structure, increasing cell membrane fluidity, reducing enzyme activities, and disrupting energy metabolism. However, in vivo antagonism by L. plantarum HJ10 primarily occurs through organic acid production and competition for growth space and nutrients. This study highlights the potential of L. plantarum HJ10 in reducing A. versicolor and STC contamination in maize.

Host tracheal and intestinal microbiomes inhibit Coccidioides growth in vitro

Coccidioidomycosis, also known as Valley fever, is a disease caused by the fungal pathogen Coccidioides. Unfortunately, patients are often misdiagnosed with bacterial pneumonia, leading to inappropriate antibiotic treatment. The soil Bacillus subtilis-like species exhibits antagonistic properties against Coccidioides in vitro; however, the antagonistic capabilities of host microbiota against Coccidioides are unexplored. We sought to examine the potential of the tracheal and intestinal microbiomes to inhibit the growth of Coccidioides in vitro. We hypothesized that an uninterrupted lawn of microbiota obtained from antibiotic-free mice would inhibit the growth of Coccidioides, while partial in vitro depletion through antibiotic disk diffusion assays would allow a niche for fungal growth. We observed that the microbiota grown on 2×GYE (GYE) and Columbia colistin and nalidixic acid with 5% sheep's blood agar inhibited the growth of Coccidioides, but microbiota grown on chocolate agar did not. Partial depletion of the microbiota through antibiotic disk diffusion revealed diminished inhibition and comparable growth of Coccidioides to controls. To characterize the bacteria grown and identify potential candidates contributing to the inhibition of Coccidioides, 16S rRNA sequencing was performed on tracheal and intestinal agar cultures and murine lung extracts. We found that the host bacteria likely responsible for this inhibition primarily included Lactobacillus and Staphylococcus. The results of this study demonstrate the potential of the host microbiota to inhibit the growth of Coccidioides in vitro and suggest that an altered microbiome through antibiotic treatment could negatively impact effective fungal clearance and allow a niche for fungal growth in vivo.

IMPORTANCE

Coccidioidomycosis is caused by a fungal pathogen that invades the host lungs, causing respiratory distress. In 2019, 20,003 cases of Valley fever were reported to the CDC. However, this number likely vastly underrepresents the true number of Valley fever cases, as many go undetected due to poor testing strategies and a lack of diagnostic models. Valley fever is also often misdiagnosed as bacterial pneumonia, resulting in 60%-80% of patients being treated with antibiotics prior to an accurate diagnosis. Misdiagnosis contributes to a growing problem of antibiotic resistance and antibiotic-induced microbiome dysbiosis; the implications for disease outcomes are currently unknown. About 5%-10% of symptomatic Valley fever patients develop chronic pulmonary disease. Valley fever causes a significant financial burden and a reduced quality of life. Little is known regarding what factors contribute to the development of chronic infections and treatments for the disease are limited.

Harnessing the Health and Techno-Functional Potential of Lactic Acid Bacteria: A Comprehensive Review

This review examines the techno-functional properties of lactic acid bacteria (LABs) in the food industry, focusing on their potential health benefits. We discuss current findings related to the techno-functionality of LAB, which includes acidification, proteolytic and lipolytic features, and a variety of other biochemical activities. These activities include the production of antimicrobial compounds and the synthesis of exopolysaccharides that improve food safety and consumer sensory experience. LABs are also known for their antioxidant abilities, which help reduce oxidative reactions in foods and improve their functional properties. In addition, LABs' role as probiotics is known for their promising effects on gut health, immune system modulation, cholesterol control, and general wellbeing. Despite these advantages, several challenges hinder the effective production and use of probiotic LABs, such as maintaining strain viability during storage and transport as well as ensuring their efficacy in the gastrointestinal tract. Our review identifies these critical barriers and suggests avenues for future research.

Influence of Limosilactobacillus fermentum IAL 4541 and Wickerhamomyces anomalus IAL 4533 on the growth of spoilage fungi in bakery products

Fungi are the main microorganisms responsible for the spoilage of bakery products, and their control and subsequent reduction of food waste are significant concerns in the agri-food industry. Synthetic preservatives are still the most used compounds to reduce bakery product spoilage. On the other hand, studies have shown that biopreservation can be an attractive approach to overcoming food and feed spoilage and increasing their shelf-life. However, limited studies show the preservation effects on real food matrices. Therefore, this study aimed to investigate the influence of microorganisms such as lactic acid bacteria (LAB) and yeasts on the growth of spoilage filamentous fungi (molds) on bread and panettones. In general, on conventional and multigrain bread, treatments containing Limosilactobacillus fermentum IAL 4541 and Wickerhamomyces anomalus IAL 4533 showed similar results when compared to the negative control (calcium propionate) in delaying the fungal growth of the tested species (Aspergillus chevalieri, Aspergillus montevidensis, and Penicillium roqueforti). Different from bread, treatments with W. anomallus in panettones delayed the A. chevalieri growth up to 30 days, 13 days longer than observed on negative control (without preservatives). This study showed that biopreservation is a promising method that can extend bakery products' shelf-life and be used as an alternative to synthetic preservatives.

Bioprotection Potential of Lacticaseibacillus rhamnosus LRH01 and Lactiplantibacillus plantarum LP01 against Spoilage-Associated Penicillium Strains in Yoghurt

Penicillium spp. are considered a major spoilage fungus in dairy products. Due to the growing concerns over food safety issues and the demand for "clean label" food products from consumers, the use of lactic acid bacteria (LAB) as a bioprotective tool to control fungal spoilage of dairy products appears to be a promising alternative. Here, the antifungal activities of ten LAB cultures against five dairy-spoilage-associated Penicillium strains were studied in a model system, and the most potent bioprotective cultures were further tested in yoghurt. Lacticaseibacillus rhamnosus (L. rhamnosus) LRH01 and Lactiplantibacillus plantarum (L. plantarum) LP01 exhibited potent antifungal efficacy at low concentrations. The inhibitory effects of cell-containing fermentates (C-fermentates), cell-free fermentates (CF-fermentates), and volatiles produced by the two cultures were tested in a yoghurt serum medium. The C-fermentates showed antifungal effects, while the removal of cells from C-fermentates led to decreased antifungal activities. Volatiles alone displayed some antifungal efficiency, but less than the fermentates. In a yoghurt matrix, the specific effect of manganese depletion by the bioprotective cultures on mold growth was investigated. Here, the LAB cultures could completely suppress the growth of molds, while addition of manganese partially or fully restored the mold growth, demonstrating that manganese depletion played a key role in the antifungal activity of the tested LAB cultures in the yoghurt matrix. Both L. plantarum LP01 and L. rhamnosus LRH01 showed efficient antifungal activities in the yoghurt serum, while L. rhamnosus LRH01 exhibited the most potent inhibitory effects on Penicillium strains when added during the processing of the yoghurt with subsequent storage at 7 °C for 22 days. Our findings suggested that L. rhamnosus LRH01 could be a promising bioprotective culture for yoghurt biopreservation.

Preservation effect of Lactobacillus plantarum O2 fermentation supernatant on postharvest pepper and its induced resistance to Phytophthora capsici

Research of lactic acid bacteria and its metabolites on biological preservatives becomes a hot topic. Lactobacillus plantarum O2, with good inhibition on Phytophthora capsici (P. capsici), was isolated from the pickle. In this study, the effects of L. plantarum O2 fermentation supernatant (FS) on pepper postharvest preservation and its induced resistance to P. capsici were studied. Results showed that weight loss rate, rot index, respiration rate, relative electrical conductivity, loss of chlorophyll content and VC of pepper in FS treatment group were decreased by 18 %, 64 %, 15 %, 26 %, 33 % and 20 % compared with blank control (BC) after 20 d storage. L* and b*-value of pepper in FS group were lower than those in the BC group. In addition, the damage-induced resistance test found that the infection rate in the FS group was reduced by 39 %, compared with CK2 after 12 d storage. Moreover, phenylalanine ammonia-lyase activity, peroxidase activity, polyphenol oxidase activity, proline content, total phenol content and flavonoid content increased by 14 %, 9 %, 30 %, 8 %, 8 % and 9 %, respectively, while malondialdehyde content decreased by 13 %. These results indicated that FS treatment showed good fresh-keeping effects on postharvest pepper. It could enhance the tolerance of pepper under stress by improving defensive enzyme activities, slowing down the damage caused by P. capsici, and inducing pepper resistance to P. capsici. Therefore, FS can be used as a microbial source bio-preservative for postharvest pepper.

Butyl succinate-mediated control of Bacillus velezensis ce 100 for apple anthracnose caused by Colletotrichum gloeosporioides

AIMS

Microbial biocontrol agents have become an effective option to mitigate the harmfulness of chemical pesticides in recent years. This study demonstrates the control efficacy of Bacillus velezensis CE 100 on the anthracnose causal agent, Colletotrichum gloeosporioides.

METHODS AND RESULTS

In vitro antifungal assays revealed that the culture filtrate and volatile organic compounds of B. velezensis CE 100 strongly restricted the mycelial development of C. gloeosporioides. Moreover, a bioactive compound, butyl succinate, was isolated from the n-butanol crude extract of B. velezensis CE 100 (bce), and identified by liquid chromatography-electrospray ionization hybrid ion-trap and time-of-flight mass spectrometry (LC-ESI-QTOF-MS) and one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR). Treatment with purified butyl succinate at a concentration of 300 μg mL-1 strongly controlled conidial germination of C. gloeosporioides with an inhibition rate of 98.66%, whereas butyl succinate at a concentration of 400 μg mL-1 showed weak antifungal action on the mycelial growth of C. gloeosporioides with an inhibition rate of 31.25%. Scanning electron microscopy revealed that the morphologies of butyl succinate-treated hyphae and conidia of C. gloeosporioides were severely deformed with shriveled and wrinkled surfaces. Furthermore, butyl succinate was able to control carbendazim-resistant C. gloeosporioides, demonstrating that it could be a promising agent for the suppression of other carbendazim-resistant fungal pathogens. An in vivo biocontrol assay demonstrated that the strain ce 100 broth culture and butyl succinate showed higher control efficacy on apple anthracnose than bce.

CONCLUSIONS

Our findings provide insight into the antifungal potential of B. velezensis  ce 100 and its butyl succinate for efficient control of phytopathogenic fungi, such as C. gloeosporiodes, in plant disease protection. This is the first study to demonstrate the antifungal potential of bacteria-derived butyl succinate for control of C. gloeosporioides.

Host tracheal and intestinal microbiomes inhibit Coccidioides growth in vitro

Coccidioidomycosis, also known as Valley fever, is a disease caused by the fungal pathogen Coccidioides. Unfortunately, patients are often misdiagnosed with bacterial pneumonia leading to inappropriate antibiotic treatment. Soil bacteria B. subtilis-like species exhibits antagonistic properties against Coccidioides in vitro; however, the antagonistic capabilities of host microbiota against Coccidioides are unexplored. We sought to examine the potential of the tracheal and intestinal microbiomes to inhibit the growth of Coccidioides in vitro. We hypothesized that an uninterrupted lawn of microbiota obtained from antibiotic-free mice would inhibit the growth of Coccidioides while partial in vitro depletion through antibiotic disk diffusion assays would allow a niche for fungal growth. We observed that the microbiota grown on 2xGYE (GYE) and CNA w/ 5% sheep's blood agar (5%SB-CNA) inhibited the growth of Coccidioides, but that grown on chocolate agar does not. Partial depletion of the microbiota through antibiotic disk diffusion revealed that microbiota depletion leads to diminished inhibition and comparable growth of Coccidioides growth to controls. To characterize the bacteria grown and narrow down potential candidates contributing to the inhibition of Coccidioides, 16s rRNA sequencing of tracheal and intestinal agar cultures and murine lung extracts was performed. The identity of host bacteria that may be responsible for this inhibition was revealed. The results of this study demonstrate the potential of the host microbiota to inhibit the growth of Coccidioides in vitro and suggest that an altered microbiome through antibiotic treatment could negatively impact effective fungal clearance and allow a niche for fungal growth in vivo.

The potential of lactic acid bacteria isolated from ikan budu (fermented fish) to inhibit the growth of pathogenic fungi and detoxify aflatoxin B1

Background and Aim

Market demand for safe feed and food supply and consumer preferences for safe and healthy products are increasing. Control measures to counter threats to the feed supply need to be implemented as early as possible to prevent economic losses. Mycotoxins produced by certain groups of fungi are a problem that can disrupt the feed supply or pose a threat to the health of animals and humans. Biological control to detoxify contaminated feed ingredients can be carried out on a large scale economically. For example, lactic acid bacteria (LAB) can act as biological agents for eliminating mycotoxins. This study aimed to clarify the value of screening LAB to inhibit Aspergillus flavus growth and detoxify aflatoxin B1 (AFB1).

Materials and Methods

In this study, using a completely randomized design with three replications, five isolates of LAB (LA.1, LA.6, LA.8, LA.12, and LA.22) along with their supernatants were tested qualitatively and quantitatively for their ability to counter mycotoxins using A. flavus and corn kernels. The isolates with the best activity were identified by sequencing 16S rDNA.

Results

The results showed that the five LAB isolates can inhibit the growth of A. flavus and detoxify AFB1. Among these isolates, LA.12 showed the best performance, followed by LA.22, LA.8, LA.6, and then LA.1. The sequencing results confirmed that LA.12 was Lactobacillus harbinensis strain 487.

Conclusion

All of the isolates in this study have the potential as biological agents for detoxifying AFB1, with isolate LA.12 appearing to be the most promising biodetoxification agent for feed (AFB1 in corn) based on its ability to inhibit pathogenic fungi.

Metabolic alterations in patients with Helicobacter pylori-related gastritis: The H. pylori-gut microbiota-metabolism axis in progression of the chronic inflammation in the gastric mucosa

PURPOSE

To characterize the serum metabolism in patients with Helicobacter pylori-positive and H. pylori-negative gastritis.

METHODS

Clinical data and serum gastric function parameters, PGI (pepsinogen I), PGII, PGR (PGI/II), and G-17 (gastrin-17) of 117 patients with chronic gastritis were collected, including 57 H. pylori positive and 60 H. pylori negative subjects. Twenty cases in each group were randomly selected to collect intestinal mucosa specimens and serum samples. The gut microbiota profiles were generated by 16S rRNA gene sequencing, and the serum metabolites were analyzed by a targeted metabolomics approach based on liquid chromatography-mass spectrometry (LC-MS) technology.

RESULTS

Altered expression of 20 metabolites, including isovaleric acid, was detected in patients with HPAG. Some taxa of Bacteroides, Fusobacterium, and Prevotella in the gut microbiota showed significant correlations with differentially expressed metabolites between H. pylori positive and H. pylori negative individuals. As a result, an H. pylori-gut microbiota-metabolism (HGM) axis was proposed.

CONCLUSION

Helicobacter pylori infection may influence the progression of mucosal diseases and the emergence of other complications in the host by altering the gut microbiota, and thus affecting the host serum metabolism.

Protective Cultures in Food Products: From Science to Market

An ultimate goal in food production is to guarantee food safety and security. Fermented food products benefit from the intrinsic capabilities of the applied starter cultures as they produce organic acids and bactericidal compounds such as hydrogen peroxide that hamper most food pathogens. In addition, highly potent small peptides, bacteriocins, are being expelled to exert antibiotic effects. Based on ongoing scientific efforts, there is a growing market of food products to which protective cultures are added exclusively for food safety and for prolonged shelf life. In this regard, most genera from the order Lactobacillales play a prominent role. Here, we give an overview on protective cultures in food products. We summarize the mode of actions of antibacterial mechanisms. We display the strategies for the isolation and characterization of protective cultures in order to have them market-ready. A survey of the growing market reveals promising perspectives. Finally, a comprehensive chapter discusses the current legislation issues concerning protective cultures, leading to the conclusion that the application of protective cultures is superior to the usage of defined bacteriocins regarding simplicity, economic costs, and thus usage in less-developed countries. We believe that further discovery of bacteria to be implemented in food preservation will significantly contribute to customer's food safety and food security, badly needed to feed world's growing population but also for food waste reduction in order to save substantial amounts of greenhouse gas emissions.

Screening and activity of potential gastrointestinal probiotic lactic acid bacteria against Yersinia ruckeri O1b

Yersiniosis of cultured Atlantic salmon is a recurrent fish health management challenge in many continents. The causative organism, Yersinia ruckeri, can reside latently in the gut and lead to acute infection and disease during hatchery and sea-transfer stages. One potential prevention approach is the administration of probiotic bacteria to suppress gut colonization of Y. ruckeri. Our study aimed to isolate and identify anti-Yersinia activity among lactic acid bacteria (LAB) isolated from the gastrointestinal tract (GIT) of aquatic animals. Of the 186 aquatic GIT isolates examined, three strains showed diffusible antimicrobial activity towards Y. ruckeri O1b. Analysis of 16 s rRNA gene sequences indicated the three bacterial strains were Enterococci, related to Enterococcus sp. (99%), Enterococcus thailandicus (99%), and Enterococcus durans (99%). Anti-Yersinia activity was maintained at neutral pH (~6.5-7.0), and in-vitro environmental tolerance assays showed the three strains could withstand simulated salmonids gastrointestinal tract conditions of: low pH (3.4) and 3% bile salt content. All three Enterococci strains showed higher adhesion to the intestinal mucus of Atlantic salmon than Y. ruckeri O1b (E. durans 24%, E. enterococcus sp. 25% and E. thailandicus 98%, compared to Y. ruckeri O1b 5%). However, only Enterococcus sp. and E. thailandicus were able to grow in the salmon intestinal mucus broth while E. durans showed no growth. Anti-Yersinia activity was completely inactivated by proteinase-K treatment, suggesting that the active compound/s are proteinaceous and may be bacteriocin-like inhibitory substances (BLIS). Our data indicate that Enterococcus sp. MA176 and E. thailandicus MA122 are potential probionts for the prevention of yersiniosis in salmonids. Further in-vivo studies are required to determine whether these bacteria reduce the incidence of yersiniosis in Atlantic salmon.

Prevention of Fungal Contamination in Semi-Hard Cheeses by Whey–Gelatin Film Incorporated with Levilactobacillus brevis SJC120

Cheese whey fermented by lactic acid bacteria (LAB) was used to develop an edible film with antifungal properties. Five LAB strains isolated from artisanal cheeses were screened for antifungal activity and incorporated into a whey–gelatin film. Of the strains tested, Levilactobacillus brevis SJC120 showed the strongest activity against five filamentous fungi isolated from cheese and cheese-making environment, at both 10 °C and 20 °C. The cell-free supernatant from L. brevis inhibited fungal growth by more than 80%. Incorporation of bacterial cells into the film did not alter the moisture content, water vapor permeability, or mechanical and optical properties. The whey–gelatin film was also able to maintain the viability of L. brevis cells at 107 log CFU/g after 30 days at 10 °C. In cheeses wrapped with L. brevis film, the size of fungal colonies decreased by 55% to 76%. Furthermore, no significant differences (p > 0.05) were observed in cheese proteolysis or in the moisture, fat, and protein content of the cheese wrapped with films. The results showed that whey–gelatin film with L. brevis SJC120 can reduce the contamination of cheese with filamentous fungi and could be used as an alternative to conventional cheese preservation and packaging.

2-hydroxy-3-phenylpropanoic acid suppressed the growth of Alternaria alternata through damaging cell membrane integrity and modulating reactive oxygen species metabolism

Black spot rot caused by Alternaria alternata is one of the major postharvest disease of apple fruit during logistic. This study evaluated in vitro inhibitory effect of 2-hydroxy-3-phenylpropanoic acid (PLA) at various concentrations on A. alternata and the possible mechanisms involved in its action. Results showed that different concentrations of PLA inhibited conidia germination and mycelial growth of A. alternata in vitro, and 1.0 g L^-1 was the lowest effective concentration to suppress A. alternata growth. Moreover, PLA significantly reduced relative conductivity and increased malondialdehyde and soluble protein contents. PLA also increased H₂O₂ and dehydroascorbic acid contents, but reduced ascorbic acid content. Additionally, PLA treatment inhibited catalase, ascorbate peroxidase, monodehydroascorbate acid reductase, dehydroascorbic acid reductase and glutathione reductase activities, whereas promoted superoxide dismutase activity. All these findings suggest that the possible mechanisms involved in the inhibitory effect of PLA on A. alternata included damaging the cell membrane integrity to cause electrolyte leakage and destroying reactive oxygen species balance.

Non-Targeted Metabolomic Profiling Identifies Metabolites with Potential Antimicrobial Activity from an Anaerobic Bacterium Closely Related to Terrisporobacter Species

This work focused on the metabolomic profiling of the conditioned medium (FS03CM) produced by an anaerobic bacterium closely related to Terrisporobacter spp. to identify potential antimicrobial metabolites. The metabolome of the conditioned medium was profiled by two-channel Chemical Isotope Labelling (CIL) LC-MS. The detected metabolites were identified or matched by conducting a library search using different confidence levels. Forty-eight significantly changed metabolites were identified with high confidence after the growth of isolate FS03 in cooked meat glucose starch (CMGS) medium. Some of the secondary metabolites identified with known antimicrobial activities were 4-hydroxyphenyllactate, 3-hydroxyphenylacetic acid, acetic acid, isobutyric acid, valeric acid, and tryptamine. Our findings revealed the presence of different secondary metabolites with previously reported antimicrobial activities and suggested the capability of producing antimicrobial metabolites by the anaerobic bacterium FS03.

Hypoglycemic Effects of Inactivated Lactobacillus brevis YM 1301 on T2DM Mice

Lactobacillus brevis (L. brevis) is a widely used probiotic with health-promoting properties. Previous studies reported that L. brevis has beneficial impacts on T2DM mice. On the other hand, the differences in effects between live and inactivated L. brevis are still inconclusive. This study aims to evaluate the hypoglycemic effects of inactivated L. brevis YM1301 (YM1301) on T2DM mice induced by a high-fat diet (HFD) combined with streptozocin (STZ). T2DM mice were randomly stratified into four groups and administered either saline (model group), metformin (positive control group), live YM1301 (LB group), or inactivated YM1301 (ILB group). Results demonstrated that inactivated YM1301 reduced serum content of fasting blood glucose, insulin, and glycated hemoglobin, enhanced the level of glucose tolerance, and decreased insulin resistance in T2DM mice. Inactivated YM1301 also decreased fat accumulation in T2DM mice. In addition, inactivated YM1301 effectively promoted serum GLP-1 levels. These results showed that inactivated YM1301 can significantly improve symptoms of T2DM. This study provides theoretical feasibility for the development of low-cost, easy to store, safer, and more effective probiotic products related to L. brevis.

Brazilian Table Olives: A Source of Lactic Acid Bacteria with Antimycotoxigenic and Antifungal Activity

Food and feed contamination by fungi, especially by toxigenic ones, is a global concern because it can pose serious health problems when the production of mycotoxins is involved. Lactic acid bacteria (LAB), well-known for fermenting foods, have been gaining attention for their antifungal and anti-mycotoxin properties. This work tested 14 LAB strains isolated from naturally fermented Brazilian table olives for growth inhibition of Aspergillus flavus, Aspergillus carbonarius, Penicillium nordicum, and Penicillium expansum. The strains Lacticaseibacillus paracasei subsp. paracasei CCMA 1764, Levilactobacillus brevis CCMA 1762, and Lactiplantibacillus pentosus CCMA 1768 showed the strongest antifungal activity, being more active against P. expansum. Aflatoxin B1 (AFB1), ochratoxin A (OTA), and patulin (PAT) production was reduced essentially by mycelia growth inhibition. The main organic acids detected in the cell free supernatant (CFS) were lactic and acetic acids. Tested LAB exhibited adsorption capacity against AFB1 (48-51%), OTA (28-33%), and PAT (23-24%). AFB1 was converted into aflatoxin B2a (AFB2a) by lactic and acetic acids produced by the strain CCMA 1764. A similar conversion was observed in solutions of these organic acids (0.1 M). These findings demonstrate the potential of isolated LAB strains as natural agents to control toxigenic fungi and their mycotoxins in fermented products, such as table olives.

Antifungal Effect of Metabolites from a New Strain Lactiplantibacillus Plantarum LPP703 Isolated from Naturally Fermented Yak Yogurt

The antifungal effect of metabolites produced by a new strain of Lactiplantibacillus (Lpb.) plantarum LPP703, isolated from naturally fermented yak yogurt, was investigated. The results showed that Lpb. plantarum LPP703 significantly inhibited four fungal species, including Penicillium sp., Rhizopus delemar, Aspergillus flavus, and Aspergillus niger. The metabolites produced after 20 h of Lpb. plantarum LPP703 fermentation showed the highest antifungal activity against Penicillium sp. Compared with the control group, the Lpb. plantarum LPP703 metabolites-treated Penicillium sp. spores were stained red by propidium iodide, indicating that the cell membrane of the fungal spores was damaged. Moreover, the antifungal effect of the Lpb. plantarum LPP703 metabolites on Penicillium sp. was not changed after heating or treatment with various proteases, but showed a sharp decrease when the pH value was regulated to 5.0 or above. The oleamide, trans-cinnamic acid, and citric acid were the three most abundant in the Lpb. plantarum LPP703 metabolites. Molecular docking predicated that the oleamide interacted with the active site of lanosterol 14-alpha-demethylase (CYP51, a crucial enzyme for fungal membrane integrity) through hydrogen bonds and had the lowest docking score, representing the strongest binding affinity to CYP51. Taken together, the metabolites from a new strain of Lpb. plantarum, LPP703, had potent antifungal activity against Penicillium sp., which might be associated with the damage of the active ingredient to fungal membrane integrity. This study indicated that Lpb. plantarum LPP703 and its metabolites might act as biological control agents to prevent fungal growth in the food industry.

Strategies for the Development of Bioprotective Cultures in Food Preservation

Consumers worldwide are increasingly demanding food with fewer ingredients, preferably without chemical additives. The trend called "Clean Label" has stimulated the development and commercialization of new types of bioprotective bacterial cultures. These bacteria are not considered new, and several cultures have been available on the market. Additionally, new bioprotective bacteria are being identified to service the clean label trend, extend the shelf life, and, mainly, improve the food safety of food. In this context, the lactic acid bacteria (LAB) have been extensively prospected as a bioprotective culture, as they have a long history in food production and their antimicrobial activity against spoilage and pathogenic microorganisms is well established. However, to make LAB cultures available in the market is not that easy, the strains should be characterized phenotypically and genotypically, and studies of safety and technological application are necessary to validate their bioprotection performance. Thus, this review presents information on the bioprotection mechanisms developed by LAB in foods and describes the main strategies used to identify and characterize bioprotective LAB with potential application in the food industry.

The Effect of Indole-3-Lactic Acid from Lactiplantibacillus plantarum ZJ316 on Human Intestinal Microbiota In Vitro

Microbiota-derived tryptophan metabolites are essential signals for maintaining gut homeostasis, yet the potential contribution to modulating gut microbiota has been rarely investigated. In this study, Lactiplantibacillus plantarum ZJ316 (CCTCC No. M 208077) with a high production (43.14 μg/mL) of indole-3-lactic acid (ILA) was screened. ILA with 99.00% purity was prepared by macroporous resin, Sephadex G–25 and reversed-phase high-performance liquid chromatography. Purified ILA can effectively inhibit foodborne pathogens such as Salmonella spp., Staphylococcus spp., Escherichia coli and Listeria monocytogenes. In an in vitro model of the human gut microbiota, a medium-dose ILA (172 mg/L) intervention increased the average relative abundance of phyla Firmicutes and Bacteroidota by 9.27% and 15.38%, respectively, while Proteobacteria decreased by 14.36% after 24 h fermentation. At the genus level, the relative abundance of Bifidobacterium and Faecalibacterium significantly increased to 5.36 ± 2.31% and 2.19 ± 0.77% (p < 0.01), respectively. Escherichia and Phascolarctobacterium decreased to 16.41 ± 4.81% (p < 0.05) and 2.84 ± 1.02% (p < 0.05), respectively. Intestinal short-chain fatty acids, especially butyric acid, were significantly increased (2.98 ± 0.72 µmol/mL, p < 0.05) and positively correlated with Oscillospira and Collinsella. Overall, ILA has the potential to regulate the gut microbiota, and an in-depth understanding of the relationship between tryptophan metabolites and gut microbiota is needed in the future.

The importance and mitigation of mycotoxins and plant toxins in Southeast Asian fermented foods

Fermented foods (ffs) and beverages are widely consumed in Southeast Asia (SEA) for their nutritional balance, flavor, and food security. They serve as vehicles for beneficial microorganisms performing a significant role in human health. However, there are still major challenges concerning the safety of ffs and beverages due to the presence of natural toxins. In this review, the common toxins found in traditional ffs in SEA are discussed with special reference to mycotoxins and plant toxins. Also, mitigation measures for preventing risks associated with their consumption are outlined. Ochratoxin, citrinin, aflatoxins were reported to be major mycotoxins present in SEA ffs. In addition, soybean-based ff food products were more vulnerable to mycotoxin contaminations. Common plant toxins recorded in ffs include cyanogenic glycosides, oxalates, phytates and saponins. Combined management strategies such as pre-harvest, harvest and post-harvest control and decontamination, through the integration of different control methods such as the use of clean seeds, biological control methods, fermentation, appropriate packaging systems, and controlled processing conditions are needed for the safe consumption of indigenous ffs in SEA.

Lactobacillus plantarum-derived postbiotics prevent Salmonella-induced neurological dysfunctions by modulating gut-brain axis in mice

Postbiotics are the inactive bacteria and/or metabolites of beneficial microbes which have been recently found to be as effective as their live probiotic. This study aimed to evaluate the benefits of Lactobacillus plantarum (LP)-derived postbiotics on ameliorating Salmonella-induced neurological dysfunctions. Mice were pretreated with LP postbiotics (heat-killed bacteria or the metabolites) or active bacteria, and then challenged with Salmonella enterica Typhimurium (ST). Results showed that LP postbiotics, particularly the metabolites, effectively prevented ST infection in mice, as evidenced by the inhibited weight loss, bacterial translocation, and tissue damages. The LP postbiotics markedly suppressed brain injuries and neuroinflammation (the decreased interleukin (IL)-1β and IL-6, and the increased IL-4 and IL-10). Behavior tests indicated that LP postbiotics, especially the metabolites, protected mice from ST-induced anxiety and depressive-like behaviors and cognitive impairment. A significant modulation of neuroactive molecules (5-hydroxytryptamine, gamma-aminobutyric acid, brain-derived neurotrophic factor, dopamine, acetylcholine, and neuropeptide Y) was also found by LP postbiotic pretreatment. Microbiome analysis revealed that LP postbiotics optimized the cecal microbial composition by increasing Helicobacter, Lactobacillus and Dubosiella, and decreasing Mucispirillum, norank_f_Oscillospiraceae, and Eubacterium_siraeum_group. Moreover, LP postbiotics inhibited the reduction of short-chain fatty acids caused by ST infection. Pearson's correlation assays further confirmed the strong relationship of LP postbiotics-mediated benefits and gut microbiota. This study highlights the effectiveness of postbiotics and provide a promising strategy for preventing infection-induced brain disorders by targeting gut–brain axis.

The Complex Role of Lactic Acid Bacteria in Food Detoxification

Toxic ingredients in food can lead to serious food-related diseases. Such compounds are bacterial toxins (Shiga-toxin, listeriolysin, Botulinum toxin), mycotoxins (aflatoxin, ochratoxin, zearalenone, fumonisin), pesticides of different classes (organochlorine, organophosphate, synthetic pyrethroids), heavy metals, and natural antinutrients such as phytates, oxalates, and cyanide-generating glycosides. The generally regarded safe (GRAS) status and long history of lactic acid bacteria (LAB) as essential ingredients of fermented foods and probiotics make them a major biological tool against a great variety of food-related toxins. This state-of-the-art review aims to summarize and discuss the data revealing the involvement of LAB in the detoxification of foods from hazardous agents of microbial and chemical nature. It is focused on the specific properties that allow LAB to counteract toxins and destroy them, as well as on the mechanisms of microbial antagonism toward toxigenic producers. Toxins of microbial origin are either adsorbed or degraded, toxic chemicals are hydrolyzed and then used as a carbon source, while heavy metals are bound and accumulated. Based on these comprehensive data, the prospects for developing new combinations of probiotic starters for food detoxification are considered.

Lactic acid bacteria: isolation-characterization approaches and industrial applications

The current state-of-art research pertaining to lactic acid bacteria (LAB) calls for the screening and isolation of robust LAB strains to achieve holistic exploitation of LAB and their metabolites of marketable importance. Hence it is imperative to comprehend LAB sources, growth requisites, isolation and characterization strategies necessary for featured cataloging and appropriate culturing. This review comprehensively describes various growth media and biomasses used for supporting LAB sustenance, assay procedures needed for the isolation and characterization of LAB strains, and their application in diverse sectors. The various industrial patents and their summarized claims about novel LAB strains isolated and identified, methods and media (used for detection/screening, isolation, adaptation, culturing, preservation, growth improvement), the techniques and/or methodologies supporting LAB fermentation, and applications of produced industrial metabolites in various market scenarios are detailed.

Antifungal Preservation of Food by Lactic Acid Bacteria

Fungal growth and consequent mycotoxin release in food and feed threatens human health, which might even, in acute cases, lead to death. Control and prevention of foodborne poisoning is a major task of public health that will be faced in the 21st century. Nowadays, consumers increasingly demand healthier and more natural food with minimal use of chemical preservatives, whose negative effects on human health are well known. Biopreservation is among the safest and most reliable methods for inhibiting fungi in food. Lactic acid bacteria (LAB) are of great interest as biological additives in food owing to their Generally Recognized as Safe (GRAS) classification and probiotic properties. LAB produce bioactive compounds such as reuterin, cyclic peptides, fatty acids, etc., with antifungal properties. This review highlights the great potential of LAB as biopreservatives by summarizing various reported antifungal activities/metabolites of LAB against fungal growth into foods. In the end, it provides profound insight into the possibilities and different factors to be considered in the application of LAB in different foods as well as enhancing their efficiency in biodetoxification and biopreservative activities.

Antifungal Activity of Lactobacillus plantarum ZZUA493 and Its Application to Extend the Shelf Life of Chinese Steamed Buns

Lactic acid bacteria (LAB) can produce many kinds of antifungal substances, which have been widely proven to have antifungal activity. In this study, 359 strains of LAB were screened for antifungal activity against Aspergillus niger (A. niger) using the 96-well microtiter plate method, and three showed strong activity. Of these, ZZUA493 showed a broad-spectrum antifungal ability against A. niger, Aspergillus oryzae, Trichoderma longibrachiatum, Aspergillus flavus and Fusarium graminearum. ZZUA493 was identified as Lactobacillus plantarum. Protease treatment, the removal of hydrogen peroxide with catalase and heat treatment had no effect on the antifungal activity of the cell-free supernatant (CFS) of ZZUA493; organic acids produced by ZZUA493 appeared to have an important role in fungal growth inhibition. The contents of lactic acid, acetic acid and phenyllactic acid in the CFS tended to be stable at 48 h, and amounted to 28.5, 15.5 and 0.075 mg/mL, respectively. In addition, adding ZZUA493, as an ingredient during their preparation, prolonged the shelf life of Chinese steamed buns. Overall, ZZUA493 appears to have good potential as a fungal inhibitor for food preservation.

Mycotoxin detoxification of food by lactic acid bacteria

Today, a few hundred mycotoxins have been identified and the number is rising. Mycotoxin detoxification of food and feed has been a technically uphill task for the industry. In the twenty-first century, the public demand is healthy food with minimum use of chemicals and preservatives. Among all the fungal inhibition and mycotoxin detoxification methods so far developed for food, biopreservation and biodetoxification have been found safe and reliable. Nowadays, lactic acid bacteria (LAB) are of great interest as biological additives in food owing to their Generally Recognized as Safe (GRAS) classification and mycotoxin detoxification capability. The occurrence of fungul growth in the food chain can lead to health problems such as mycotoxicosis and cancer to humans due to producing mycotoxins such as aflatoxins. Biopreservation is among the safest and most reliable methods for inhibition of fungi in food. This review highlights the great potential of LAB as biodetoxificant by summarizing various reported detoxification activities of LAB against fungal mycotoxins released into foods. Mechanisms of mycotoxin detoxification, also the inherent and environmental factors affecting detoxifying properties of LAB are also covered.

The Interactions among Isolates of Lactiplantibacillus plantarum and Dairy Yeast Contaminants: Towards Biocontrol Applications

Yeast diversity in the cheese manufacturing process and in the cheeses themselves includes indispensable species for the production of specific cheeses and undesired species that cause cheese defects and spoilage. The control of yeast contaminants is problematic due to limitations in sanitation methods and chemicals used in the food industry. The utilisation of lactic acid bacteria and their antifungal products is intensively studied. Lactiplantibacillus plantarum is one of the most frequently studied species producing a wide spectrum of bioactive by-products. In the present study, twenty strains of L. plantarum from four sources were tested against 25 species of yeast isolated from cheeses, brines, and dairy environments. The functional traits of L. plantarum strains, such as the presence of class 2a bacteriocin and chitinase genes and in vitro production of organic acids, were evaluated. The extracellular production of bioactive peptides and proteins was tested using proteomic methods. Antifungal activity against yeast was screened using in vitro tests. Testing of antifungal activity on artificial media and reconstituted milk showed significant variability within the strains of L. plantarum and its group of origin. Strains from sourdoughs (CCDM 3018, K19-3) and raw cheese (L12, L24, L32) strongly inhibited the highest number of yeast strains on medium with reconstituted milk. These strains showed a consistent spectrum of genes belonging to class 2a bacteriocins, the gene of chitinase and its extracellular product 9 LACO Chitin-binding protein. Strain CCDM 3018 with the spectrum of class 2a bacteriocin gene, chitinase and significant production of lactic acid in all media performed significant antifungal effects in artificial and reconstituted milk-based media.

Efficacy of lactic acid bacteria supplementation against Fusarium graminearum growth in vitro and inhibition of Zearalenone causing inflammation and oxidative stress in vivo

Fusarium graminearum invasion and Zearalenone (ZEN)-mycotoxin contamination are considered the most global threat to food and feed. This study investigates the effect Lactobacillus plantarum MON03 viable cells (LPVC) and LP free cells supernatant (LPFCS) against Fusarium graminearum growth and ZEN production in vitro and evaluates if treatment with LP viable cells can counteract the negative effect of ZEN on inflammation and oxidative stress in mesenteric lymph nodes and serum biochemical parameters in mice. For the in vitro study, 7 days of LPVC, LPFCS and F. graminearum co-incubation at different concentrations was done in order to determine the antifungal activity and ZEN- production inhibition. Regarding the in vivo study, Balb/c mice were treated as following: Control, ZEN group, LP group and ZEN + LP group for 30 days. In vitro, LPVC showed an excellent antifungal activity after 7 days of co-incubation (10³ CFU/ml). LPVC was succeeded also to inhibit ZEN production by the fungi. In vivo, ZEN has shown an important oxidative damage. As a result of the exposure to ZEN, an increase cytokines, as effectors of an inflammatory response, were observed in the mesenteric lymph nodes (MLN) of intoxicated mice. In parallel, a serum biochemical change was also observed. LPVC induced a reduction of ZEN-induced oxidative stress and counteracts also the biochemical parameters damage and the inflammatory markers increased by ZEN. LPVC can be valorized as an anti-cating agent in the vitro and in the gastro-intestinal tract to decrease ZEN-toxic effects.

Debaryomyces hansenii Strains Isolated From Danish Cheese Brines Act as Biocontrol Agents to Inhibit Germination and Growth of Contaminating Molds

The antagonistic activities of native Debaryomyces hansenii strains isolated from Danish cheese brines were evaluated against contaminating molds in the dairy industry. Determination of chromosome polymorphism by use of pulsed-field gel electrophoresis (PFGE) revealed a huge genetic heterogeneity among the D. hansenii strains, which was reflected in intra-species variation at the phenotypic level. 11 D. hansenii strains were tested for their ability to inhibit germination and growth of contaminating molds, frequently occurring at Danish dairies, i.e., Cladosporium inversicolor, Cladosporium sinuosum, Fusarium avenaceum, Mucor racemosus, and Penicillium roqueforti. Especially the germination of C. inversicolor and P. roqueforti was significantly inhibited by cell-free supernatants of all D. hansenii strains. The underlying factors behind the inhibitory effects of the D. hansenii cell-free supernatants were investigated. Based on dynamic headspace sampling followed by gas chromatography-mass spectrometry (DHS-GC-MS), 71 volatile compounds (VOCs) produced by the D. hansenii strains were identified, including 6 acids, 22 alcohols, 15 aldehydes, 3 benzene derivatives, 8 esters, 3 heterocyclic compounds, 12 ketones, and 2 phenols. Among the 71 identified VOCs, inhibition of germination of C. inversicolor correlated strongly with three VOCs, i.e., 3-methylbutanoic acid, 2-pentanone as well as acetic acid. For P. roqueforti, two VOCs correlated with inhibition of germination, i.e., acetone and 2-phenylethanol, of which the latter also correlated strongly with inhibition of mycelium growth. Low half-maximal inhibitory concentrations (IC50) were especially observed for 3-methylbutanoic acid, i.e., 6.32-9.53 × 10-5 and 2.00-2.67 × 10-4 mol/L for C. inversicolor and P. roqueforti, respectively. For 2-phenylethanol, a well-known quorum sensing molecule, the IC50 was 1.99-7.49 × 10-3 and 1.73-3.45 × 10-3 mol/L for C. inversicolor and P. roqueforti, respectively. For acetic acid, the IC50 was 1.35-2.47 × 10-3 and 1.19-2.80 × 10-3 mol/L for C. inversicolor and P. roqueforti, respectively. Finally, relative weak inhibition was observed for 2-pentanone and acetone. The current study shows that native strains of D. hansenii isolated from Danish brines have antagonistic effects against specific contaminating molds and points to the development of D. hansenii strains as bioprotective cultures, targeting cheese brines and cheese surfaces.

Compartmentalization of bacterial and fungal microbiomes in the gut of adult honeybees

The core gut microbiome of adult honeybee comprises a set of recurring bacterial phylotypes, accompanied by lineage-specific, variable, and less abundant environmental bacterial phylotypes. Several mutual interactions and functional services to the host, including the support provided for growth, hormonal signaling, and behavior, are attributed to the core and lineage-specific taxa. By contrast, the diversity and distribution of the minor environmental phylotypes and fungal members in the gut remain overlooked. In the present study, we hypothesized that the microbial components of forager honeybees (i.e., core bacteria, minor environmental phylotypes, and fungal members) are compartmentalized along the gut portions. The diversity and distribution of such three microbial components were investigated in the context of the physico-chemical conditions of different gut compartments. We observed that changes in the distribution and abundance of microbial components in the gut are consistently compartment-specific for all the three microbial components, indicating that the ecological and physiological interactions among the host and microbiome vary with changing physico-chemical and metabolic conditions of the gut.

Sensitivity of Molds From Spoiled Dairy Products Towards Bioprotective Lactic Acid Bacteria Cultures

Fungal spoilage of dairy products is a major concern due to food waste and economical losses, some fungal metabolites may furthermore have adverse effects on human health. The use of lactic acid bacteria (LAB) is emerging as a potential clean label alternative to chemical preservatives. Here, our aim was to characterize the growth potential at three storage temperatures (5, 16, and 25°C) of a panel of molds (four Mucor and nine Penicillium strains) isolated from dairy products, then investigate the susceptibility of the molds toward 12 LAB cultures. Fungal cell growth and morphology in malt extract broth was monitored using oCelloScope at 25°C for 24 h. Mucor plumbeus 01180036 was the fastest growing and Penicillium roqueforti ISI4 (P. roqueforti ISI4) the slowest of the tested molds. On yogurt-agar plates, all molds grew at 5, 16, and 25°C in a temperature-dependent manner with Mucor strains growing faster than Penicillium strains regardless of temperature. The sensitivity toward 12 LAB cultures was tested using high-throughput overlay method and here all the molds except P. roqueforti ISI4 were strongly inhibited. The antifungal action of these LAB was confirmed when spotting mold spores on agar plates containing live cells of the LAB strains. However, if cells were removed from the fermentates, the inhibitory effects decreased markedly. The antifungal effects of volatiles tested in a plate-on-plate system without direct contact between mold and LAB culture media were modest. Some LAB binary combinations improved the antifungal activity against the growth of several molds beyond that of single cultures in yogurt serum. The role of competitive exclusion due to manganese depletion was examined as a possible antifungal mechanism for six Penicillium and two Mucor strains. It was shown that this mechanism was a major inhibition factor for the molds tested apart from the non-inhibited P. roqueforti ISI4 since addition of manganese with increasing concentrations of up to 0.1 mM resulted in partly or fully restored mold growth in yogurt. These findings help to understand the parameters influencing the mold spoilage of dairy products and the interactions between the contaminating strains, substrate, and bioprotective LAB cultures.

In vitro activity of encapsulated lactic acid bacteria on aflatoxin production and growth of Aspergillus Spp

This study aimed to investigate the potential ability of simultaneously used L. acidophilus(LA-5), L.rhamnosus(LGG), and L.casei(LC-01) in encapsulated (E) and nonencapsulated (NE) forms in mycelial growth of Aspergillus spp and aflatoxin production by A. flavus. In order to assess the zone of fungal growth inhibition by E and NE lactic acid bacteria, the agar well diffusion method was applied. Quantification of aflatoxin was performed using a high-performance liquid chromatography technique. Lactic acid bacteria exhibited high antifungal activity and significantly reduced AFB1, AFB2, AFG1, and AFG2 production in both E and NE forms compared to the control group. The percentage of reduction in total AFs production in treated samples with E and NE lactic acid bacteria was 94.1% and 95.5%, respectively. These results suggested that simultaneously used lactic acid bacteria in E and NE forms can prevent growth and decrease aflatoxin production of toxigenic aspergilla.

Chemistry, Safety, and Challenges of the Use of Organic Acids and Their Derivative Salts in Meat Preservation

Meat industries are constantly facing new waves of changes in the consumer’s nutritional trends, food safety, and quality requirements and legislations leading to an increase in interest for meat biopreservation to respond to all of these modern socioeconomic demands. Hence, to replace synthetic and/or expensive additives, new technologies in preserving meat products from microbial contamination have been established. In this context, organic acids and their salts have been considered as the most popular examples of preservatives that offer several advantages to be applied in meat industry. Here, characteristics of organic acids/salts commonly used in meat preservation were described based on the published literature. Moreover, after outlining the challenges and advantages of their use in meat industry, their current applications as meat preservatives on various meat type matrices such as beef, pork, sheep, and poultry were quite exposed based on previous and recent research works. Then, different application types were highlighted. Besides, some potent synergistic approaches based on several combinations of organic acids/salts with different existing preservative techniques are reported with an emphasised discussion of their application as possible solution tools to mainly overcome some problems linked to organic acids/salts when used solely, thus contributing to ensure the overall safety and improve the quality of meats. Finally, despite their usefulness in meat preservation, organic acids/salts may possess detrimental traits. In this context, a detailed discussion on their limits of use in meat products was provided in the last section of this paper.

Microbiota succession during aerobic stability of maize silage inoculated with Lentilactobacillus buchneri NCIMB 40788 and Lentilactobacillus hilgardii CNCM-I-4785

Aerobic deterioration of silage following feeding out is responsible for the deterioration of its quality. Inoculation of silage with lactic acid bacteria is one strategy to limit these effects. A trial was performed using whole‐plant corn ensiled in bag silo, and forage was inoculated with Lentilactobacillus buchneri NCIMB 40788 (Lactobacillus buchneri) and Lentilactobacillus hilgardii CNCM‐I‐4785 (Lactobacillus hilgardii) or not (Control silage). After 159 days of fermentation, the silos were opened and the silage was sampled at 24‐h intervals during a 10‐day aerobic stability assay to measure pH, the fermentation profile, mycotoxins, and microbial and fungal populations. In inoculated silage, lactic acid concentrations and pH remained stable during the aerobic phase and higher microorganism alpha‐diversity was observed. Treated silage was characterized by a high abundance of Saccharomycetes and maintenance of Lactobacillus throughout the aerobic stability assay. The high aerobic stability of the inoculated silage contrasted with the decrease in lactic acid contents and the increase in pH observed in the Control silage, concomitantly with an increase in lactate‐assimilating yeast (Pichia and Issatchenkia), and in Acetobacter and Paenibacillus OTUs. Remarkably, Penicillium and roquefortine C were detected in this silage by day 8 following exposure to air. Our study highlighted the fact that the use of L. buchneri with L. hilgardii modified the consequences of exposure to air by maintaining higher microbial diversity, avoiding the dominance of a few bacteria, and preventing fungi from having a detrimental effect on silage quality.

A review on preparation and chemical analysis of postbiotics from lactic acid bacteria

Postbiotics may be defined as soluble metabolites released by food-grade microorganisms during the growth and fermentation in complex microbiological culture, food or gut. It is rich in high and low molecular weight biologically active metabolites. There are still gaps concerning these substances, mainly how to use them for food applications. Although the most recent work on preparation and application of postbiotics from several probiotics are very encouraging, the suitability of postbiotics to combat microorganisms that deal with food safety should be tested mainly by analyzing the chemical composition and conducting antagonistic tests. Consequently, foods can effectively benefit from an identified postbiotic with a defined effect. This review approached the recent advances in relation to the preparation of postbiotics from lactic acid bacteria. The function of different instrumental analysis techniques and factors affecting the chemical composition of postbiotics were also comprehensively reviewed.

In Vitro Antimicrobial and Antioxidant Activities of Lactobacillus coryniformis BCH-4 Bioactive Compounds and Determination of their Bioprotective Effects on Nutritional Components of Maize (Zea mays L.)

Lactic acid bacteria (LAB) can synthesize antimicrobial compounds (AMCs) with nutritional and bioprotective properties in crops and food products. In the current study, AMCs of Lactobacillus coryniformis BCH-4 were evaluated to control fungal spoilage in maize grains. On maize grains treated with 75%-100% (v/v) concentrated AMCs, no fungal growth was observed even after 72 h of Aspergillus flavus inoculation. Proximate analysis of treatments A1 (raw grains), A2 (A. flavus inoculated grains) and A3 (A. flavus + AMCs inoculated grains) revealed that moisture was significantly (p ≤ 0.05) high in A2 than A3 and A1. Meanwhile, protein, fat, fiber and ash contents were significantly decreased in A2 compared to A1 and A3. Moreover, β-carotene contents were not statistically different between A1 and A3, while in A2 it was significantly decreased. HPLC analysis revealed the presence of 2-oxopropanoic acid, 2-hydroxypropane-1,2,3-tricarboxylic acid, 2-hydroxybutanedioic acid, 2-hydroxypropanoic acid, propanedioic acid and butanedioic acid, which also showed antifungal activity against Aspergillus flavus. FTIR spectroscopy revealed the presence of hydroxyl, carbonyl and ester-groups along with organic and fatty acids, thereby indicating their participation in inhibitory action. Furthermore, the AMCs were found to be a good alternative to chemical preservatives, thereby not only preserving the nutritive qualities but increasing the shelf life as well.

Identification and characterization of Vietnamese coffee bacterial endophytes displaying in vitro antifungal and nematicidal activities

The endophytic bacteria were isolated from coffee roots and seeds in Vietnam and identified with 16S rDNA sequencing as belonging to the Actinobacteria, Firmicutes and Proteobacteria phyla with the Nocardia, Bacillus and Burkholderia as dominant genera, respectively. Out of the thirty genera recovered from Coffea canephora and Coffea liberica, twelve were reported for the first time in endophytic association with coffee including members of the genera Brachybacterium, Caballeronia, Kitasatospora, Lechevalieria, Leifsonia, Luteibacter, Lysinibacillus, Mycolicibacterium, Nakamurella, Paracoccus, Sinomonas and Sphingobium. A total of eighty bacterial endophytes were characterized in vitro for several plant growth promoting and biocontrol traits including: the phosphate solubilization, the indolic compounds, siderophores, HCN, esterase, lipase, gelatinase and chitinase production. A subset of fifty selected bacteria were tested for their potential as biocontrol agents with in vitro confrontations with the fungal pathogen Fusarium oxysporum as well as the coffee parasitic nematodes Radopholus duriophilus and Pratylenchus coffeae. The three most efficient isolates on F. oxysporum belonging to the Bacillus, Burkholderia, and Streptomyces genera displayed a growth inhibition rate higher than 40%. Finally, five isolates from the Bacillus genus were able to lead to 100% of mortality in 24 h on both R. duriophilus and P. coffeae.