Impact of natural antimicrobials on survival behavior and cell morphology of acid-stressed pathogens in ready-to-eat rice.

Bacillus cereus (B. cereus) is a prevalent foodborne pathogen. This study evaluated the antimicrobial efficacy and mechanism of the peptide Temporin L against B. cereus. Quantitative assays showed that Temporin L had a minimum inhibitory concentration (MIC) of 8 µM and a minimum bactericidal concentration (MBC) of 16 µM. Complete bacterial eradication occurred within 1h at 2 MIC, and complete inhibition was observed within 24h at MIC and 2 MIC. The peptide retained over 90% antibacterial activity under ultraviolet (UV) light, at high temperatures (up to 100°C), and under various metal-ion conditions, with Fe ions reducing activity to 82.11%. Membrane integrity assays indicated concentration-dependent increases in PI fluorescence (1.9-2.4 fold) and in leakage of intracellular biomolecules. Metabolic enzyme activities (NaK-ATPase, SDH, LDH) and intracellular ATP levels were significantly reduced, with SDH and LDH dropping from ~ 39/43 to ~ 10 U/mg protein after 1h at 2 MIC. Oxidative stress markers showed elevated ROS, decreased antioxidant capacity, increased lipid peroxidation, and reduced SOD activity, confirming the multifaceted bacterial damage mechanism induced by Temporin L.

Beneficial microbes are increasingly applied as biocontrol agents to enhance soil vitality and crop productivity. However, given that alterations in soil conditions can propagate across trophic levels, it is essential to evaluate the broader ecological effects and biosafety of soil-applied microorganisms on higher trophic organisms. This study investigates the impact of two beneficial soil-applied microbes, Bacillus cereus and Chryseobacterium cucumeris, on the soil-borne plant pathogenic fungus Fusarium oxysporum, cucumber, the two-spotted spider mite Tetranychus urticae and its predator Phytoseiulus persimilis. Both bacterial agents were effective against F. oxysporum and demonstrated the ability to be transmitted across plant-herbivore-predator trophic levels. Notably, B. cereus was vertically transmitted from adults to eggs in P. persimilis, whereas C. cucumeris was only detected in the digestive tract. Bacillus cereus had no significant effects on fitness of both mite species. In contrast, C. cucumeris significantly reduced survival and reproduction of T. urticae and survival of P. persimilis adults, but not egg production. Greenhouse trials confirmed that soil application of C. cucumeris around the roots of cucumber, and subsequent uptake in the foliage could significantly suppress the survival and reproduction of both mite species. This study demonstrates that soil-introduced biocontrol microbes can transmit across trophic levels and may exert non-target effects on predators. The findings underscore the importance of considering indirect ecological risks and biosafety implications for beneficial invertebrates when deploying microbial biocontrol agents in integrated pest management systems. © 2026 Society of Chemical Industry.

Anti-proliferative and antibacterial homoisoflavonoids from Pterolobium punctatum.

Genetic characterization and mutagenesis of fat-degrading enzymes from Bacillus cereus for enhanced lipid degradation and esterification.

Bacillus cereus ZW21-derived VOCs, hydroxyacetone and 3-methyl-3-buten-1-ol, control postharvest papaya anthracnose through direct antifungal activity and host transcriptional reprogramming.

The alarming rise of multidrug-resistant microbial infections underscores the urgent need for novel antimicrobial agents. A series of new pyrazole-based derivatives incorporating naphthalene and hydrazone pharmacophores were designed, synthesized, and studied for their antimicrobial activity with computational investigations. Two pyrazole-naphthalene-hydrazone hybrid types were synthesized and structurally characterized. The antimicrobial activity was systematically evaluated against Escherichia coli, Helicobacter pylori, Bacillus cereus, Staphylococcus aureus, and Candida albicans using the well diffusion method while investigating minimum inhibitory concentration (MIC). Molecular docking was also conducted to investigate the binding affinity of potent products against microbial targets (PDB IDs 3t88, 3ty7, and 5k04). Density function theory (DTF) investigation was also performed. Compounds 3g and 4d demonstrated broad-spectrum antimicrobial activity with MIC values superior or comparable to the reference drug gentamicin. The results confirm that structural modifications at key positions on the pyrazole system, particularly with electron-withdrawing and bulky aromatic substituents, significantly enhanced activity. Molecular docking revealed enhanced binding interactions for possible inhibitory effects. DFT calculations showed insights into the electronic structure, molecular orbitals, and electrostatic potential of compound 3g. The results revealed the pyrazole-naphthalene hybrids as promising candidates for the development of new antimicrobial agents.

We report a cluster of acute gastrointestinal illness in seven preterm neonates temporally associated with a single batch of powdered human milk fortifier (HMF). Symptoms developed within 3-4h of ingestion and included profuse diarrhea, dehydration, hypoglycemia, and shock. Blood and stool cultures were sterile. Microbiological analysis of unopened HMF sachets revealed contamination with Bacillus cereus and other spore-forming organisms. Withdrawal of the implicated batch and reinforcement of infection-control measures resulted in no further cases. This outbreak highlights the risk of pathogenic contamination of powdered HMF in neonatal intensive care units.

On-site detection of airborne foodborne pathogens using a field-deployable recombinase polymerase amplification and CRISPR/Cas12a cleavage activity assay.

Bacillus toyonensis is a gram-positive bacterium within the Bacillus cereus group, primarily recognized for its probiotic properties. Recently, a strain designated B. toyonensis biovar Thuringiensis (Bto_UNVM-94) was reported to produce parasporal crystals with dual insecticidal activity against Cydia pomonella and Anthonomus grandis. In this study, we describe and characterize a previously undescribed strain, B. toyonensis biovar Thuringiensis Bto_UNVM-42, which exhibits nematicidal and nematostatic activity, representing the first report of these effects within this species. Whole-genome sequencing revealed the presence of a large plasmid containing multiple putative pesticidal genes, including five cry genes encoding Cry32-like proteins, two additional cry genes encoding Cry69-like and Cry73-like proteins, three cyt genes encoding Cyt1-like proteins, and two mpp genes encoding Mpp-like proteins. In addition, the genome encodes four chitinases and two proteins with significant similarity to the nematicidal Sep1 protease from Bacillus firmus. Proteomic analysis of parasporal crystals confirmed the expression of Cry32-family proteins. Bioassays showed that strain Bto_UNVM-42 was not toxic to Aedes aegypti, Alphitobius diaperinus, Anthonomus grandis, Cydia pomonella or Drosophila suzukii. In contrast, it exhibited nematicidal activity against Panagrellus redivivus, low but detectable mortality (8%) against Meloidogyne javanica, and a reversible nematostatic effect on Pratylenchus zeae. Taken together, the available bioassay observations and the genomic and proteomic data are consistent with a predominantly enzyme-driven rather than a classical crystal toxin-mediated mode of action. Overall, these findings expand the known biocidal spectrum of B. toyonensis and highlight its potential relevance for the development of biological strategies for nematode management.

Isolation and functional characterization of a bacteriophage targeting pathogenic Bacillus cereus in Trionyx sinensis.

Salad vegetables are essential in our daily diet because they provide affordable nutrients. However, they can serve as vectors for the transfer of antibiotic resistance to consumers. In this study, we demonstrated an inter-farm measurement that provides a unique assessment to better understand the proximate causes of drug resistance in human food chains. Salad vegetable samples (cucumber, carrot and tomato) were collected from three agricultural farms in Kharkhari, Rajshahi, Bangladesh. Isolation of tetracycline-resistant bacteria was carried out by the agar dilution method using nutrient agar supplemented with 32 µg/ml tetracycline at 37ºC for 24 hours. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disc diffusion method on Mueller Hinton agar using commercial antibiotic discs. Resistant isolates were identified by 16S rRNA sequencing. A total of 34 tetracycline-resistant bacteria were isolated randomly from three types of salad vegetables to determine their susceptibility to ampicillin, kanamycin and ciprofloxacin. The result shows three resistance patterns among vegetable isolates in a very close geographical area, suggesting various patterns of drug resistance in environmental bacteria. The bacteria identified are: Enterobacter cloacae, Bacillus cereus, Chryseobacterium spp., Pseudomonas sp., and Enterobacter sp. The presence of antibiotic-resistant bacteria in agricultural products of plant origin may offer valuable information on the transmission of resistant bacteria from farms to consumers via the food chain, raising serious concerns for human health.

Since late 2025, precautionary recalls of specific infant and follow-on formula batches in Europe have occurred due to contamination with cereulide, a heat- and acid-stable emetic toxin produced by certain Bacillus cereus strains. Contamination was traced to arachidonic acid (ARA)-containing algal oil from a single supplier; no viable bacteria were detected in the affected products. The European Food Safety Authority established a conservative acute reference dose for infants, and available monitoring data indicate that detected concentrations were generally low and unlikely to pose significant health risks, although some batches may have exceeded precautionary thresholds. This commentary reviews the toxicological background, current risk assessment, analytical challenges, and clinical implications. While cereulide should not be present beyond unavoidable trace levels in infant formula, risk management must remain proportionate and avoid promoting nutritionally inadequate substitutes. Ensuring validated analytical surveillance, stringent raw material control, transparent communication, and continued provision of appropriately regulated formulas containing recommended long-chain polyunsaturated fatty acids, including docosahexaenoic acid (DHA) and ARA, is essential to safeguard infant health and maintain public confidence.

Lactiplantibacillus plantarum is widely recognized for its probiotic and technological applications in fermented foods. This study comprehensively evaluated traditionally fermented bamboo shoot products from Tripura, India, as a source of functional lactic acid bacteria through safety assessment, in vitro probiotic characterization, antimicrobial activity, and whole-genome sequencing. A total of 160 bacterial isolates were obtained, among which eight exhibited high β-glucosidase activity. Among these, strain MP49 demonstrated the highest functional potential and was selected for detailed characterization. The strain showed tolerance to acidic conditions (pH 3) and bile salts (1%), along with auto-aggregation (77.55 ± 2.28%), co-aggregation (> 95%), and cell surface hydrophobicity (> 96%), indicating strong probiotic attributes. MP49 exhibited broad antimicrobial activity against Escherichia coli, Bacillus cereus, and Staphylococcus aureus, with inhibition zones up to 25mm. Whole-genome analysis revealed probiotic-related genes for stress tolerance, adhesion, bacteriocin production, and diverse carbohydrate metabolism pathways supporting functional potential. Importantly, no virulence determinants or known transferable antimicrobial resistance genes were identified in the genome. Although mobile genetic element-related genes and insertion sequence families were detected, these findings are common in lactic acid bacteria and do not necessarily indicate safety risks. Therefore, the strain is considered to exhibit a favorable predicted safety profile based on the available genomic evidence. Lactiplantibacillus plantarum MP49 represents a functionally promising probiotic candidate from fermented bamboo shoots with potential for future application in functional food development, subject to further validation in host-cell, animal, and clinical studies.

This study aimed to evaluate the effects of high-pressure processing (HPP) on microbial safety and physicochemical quality of raw beef intended for use in raw pet food, with particular emphasis on microbial inactivation and physicochemical characteristics changes during refrigerated storage. Beef samples were treated at pressures of 0.1, 100, 300, and 500MPa for 5-15min and stored at refrigerated conditions for up to 2 weeks. Microvial populations, including Salmonella Typhimurium, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus, were enumerated during storage. Physicochemical properties, including proximate composition, pH, color, water-holding capacity, shear force, thiobarbituric acid reactive substances (TBARS), and volatile basic nitrogen (VBN), were also analyzed. Microbial counts decreased with increasing pressure and holding time. The 500MPa for 15min treatment reduced S. Typhimurium to below the detection limit (< 1 log CFU/g) throughout storage, while other pathogens showed substantial reductions with limited regrowth. HPP did not affect proximate composition of pH; however, higher pressures increased lightness, yellowness, shear force, WHC, and TBARS, while redness decreased. VBN levels decreased with increasing pressure but increased during storage. HPP effectively enhanced microbial safety of raw beef while inducing pressure and time-dependent physicochemical changes associated with muscle protein denaturation, myoglobin oxidation, and enzyme inactivation. These results support HPP as a promising intervention for improving the safety of raw pet food, although quality changes should be considered in process optimization.

This study investigated the effects of high hydrostatic processing on the microbial safety and physicochemical properties of raw pork. Raw pork samples were treated at pressures of 0.1, 100, 300, and 500MPa for 5-15min and stored under refrigerated conditions for up to 2 weeks. Microbial populations, including Bacillus cereus, Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, were analyzed alongside physicochemical properties such as proximate composition, pH, water-holding capacity (WHC), shear force, thiobarbituric acid reactive substance, and volatile basic nitrogen. Microbial count decreased significantly with increasing pressure and holding time. The 500MPa for 15min treatment exhibited the strongest antimicrobial effect, reducing S. Typhimurium and L. monocytogenes to below detectable levels during storage. B. cereus, E. coli, and S. aureus showed substantial reductions, although partial survival was observed in pressure-tolerant microorganisms during storage. Increasing pressure and treatment time led to increases in water-holding capacity, shear force, and pH, while moisture and protein contents increased and fat and ash contents decreased. These physicochemical changes were attributed to pressure-induced denaturation and reorganization of myofibrillar proteins, resulting in a compact protein network. TBARS values increased due to high-pressure-induced membrane damage and the release of ions and free radicals, whereas VBN values were suppressed by microbial inactivation and pressure-induced enzyme modification. Increasing pressure intensity and holding time enhanced both microbial inactivation and physicochemical changes, indicating that high hydrostatic processing exerts combined physical and chemical effects on microorganisms, muscle fibers, myoglobin, and enzymes in raw pork.

Salinity negatively affects seed germination and crop yields. This study explored chitinolytic bacteria from the Lipar Pink Wetland as potential wheat seed-priming agents under salt stress. Using shrimp shell waste, chitinase-producing bacteria were isolated, and their live cells and chitinase-active supernatants produced on colloidal chitin were tested as wheat seed-priming treatments in normal and saline conditions. Chitin extraction from shrimp shells using a conventional acid-alkali process yielded 53.3-56.7% chitin on a dry-weight basis. FTIR analysis confirmed characteristic functional groups, and FESEM revealed a compact, flake-like morphology. Among 45 bacterial isolates screened on chitin-containing media, three strains (S1, S49, and S80) formed clear hydrolysis halos and were selected for further analysis. Their chitinase-active extracellular fractions showed broad activity across 35-50°C, with optimum temperatures of 40°C for Sup49 and 45°C for Sup1 and Sup80. Sup1 exhibited the highest activity under acidic conditions, whereas Sup49 and Sup80 performed best at near-neutral to slightly alkaline pH. Sup80 also showed superior thermostability at 60°C and greater tolerance to salinity and EDTA than the other fractions. Partial 16S rRNA phylogeny placed S49 and S80 within Bacillus cereus sensu lato-related lineages. Seed priming showed that 150 mM sodium chloride reduced wheat performance, decreasing germination in the untreated control from 73.74 ± 7.82% under normal conditions to 34.44 ± 1.92% under salinity. Under normal conditions, shorter priming durations were generally more effective. Hydropriming for 3 and 7h produced high germination rates, while N-S80.3h produced the numerically greatest total seedling length. Under salinity, S-Sup1.3h showed the strongest numerical overall response, increasing germination to 74.67 ± 4.62% and producing the highest shoot length, root length, total seedling length, and seedling vigor index among saline treatments with available growth data. However, its GP was statistically grouped with S-Hydropriming.24h and S-Sup49.7h. Chitinolytic Bacillus-related isolates and their chitinase-active extracellular supernatants showed preliminary potential for wheat seed priming under salinity. Because the supernatants were not purified chitinase preparations, their effects may reflect combined extracellular metabolites and chitin-derived products. Future research should focus on microbial traits, plant stress physiology, pathogen challenges, biosafety, and field performance.

Cinnamon-loaded PVA/gelatin/starch electrospun fibers as novel sustainable nanocomposites for active food packaging.

β-Amino acid-containing macrolactams (β-AACMs) are a class of bioactive natural products characterized by nitrogen-containing starter units within polyketide-derived macrocycles. Here, we report four previously undescribed macrolactams, gruelactams A-D (1-4), from Nonomuraea sp. 0L2P, discovered through an integrated approach combining genome mining, 15N-labeling, and antibacterial screening. Their planar structures were elucidated by comprehensive spectroscopic analyses, including 1D and 2D NMR and HRESI-MS, and their configurations were partially assigned based on ROESY data and bioinformatic analysis. Genome sequencing and antiSMASH analysis identified a putative type I polyketide synthase (PKS) biosynthetic gene cluster, enabling the proposal of a biosynthetic pathway. Bioactivity assays showed that gruelactam D (4) exhibits antibacterial activity against Bacillus cereus and Staphylococcus aureus, with MIC values of 8 and 16 μg/mL, respectively. These findings expand the chemical diversity of β-AACMs and demonstrate the utility of genome-guided approaches for discovering bioactive natural products from rare actinomycetes.

Bacillus weihenstephanensis KBAB4 is a Gram-positive bacterial strain belonging to the group Bacillus cereus. In this study, the impact of the physiological state on acetic acid resistance and on growth limits was investigated. Strain KBAB4 was cultivated in BHI medium to produce reference cells (BHI, pH 7.2), HCl-adapted cells (BHI, pH 5.5) or acetic acid-adapted cells (BHI, pH 5.5+14mM of acetic acid). The bacterial resistance of these cells was measured by inactivation, monitoring the reduction of the bacterial concentration in BHI, pH 5.5 + 150mM of acetic acid. The growth limits of reference or acid-adapted cells were assessed on 96-well plates with BHI medium supplemented with HCl (pH 4.6 to 5.2) or acetic acid (from 14mM to 150mM). The acid resistance (δ, i.e. the first decimal decrease) during inactivation increased almost 3-fold for the HCl-adapted cells and 5-fold for the acetic acid-adapted cells, compared to the reference cells. The pH growth limits and the minimal inhibitory concentration of acetic acid were not affected by HCl adaptation, whereas they were modified for acetic acid-adapted cells. For strain KBAB4, within an isogenic population, the bacterial life history influences the inactivation time during lethal acetic acid exposure, as well as the growth limits. This raises the question of whether this factor should be considered in the assessment of microbiological risks in food safety models for other B. cereus strains, since variability in the physiological state could be a decisive factor influencing food safety.