Search Results (174)

Antimicrobial food packaging is considered a promising technology to improve food safety by inhibiting or reducing the growth of food microorganisms and minimizing the need for preservatives. This study aimed to develop and evaluate carboxymethyl cellulose (CMC) films integrated with bacteriocins for antibacterial efficacy. Plantaricin W was assessed as a potential bacteriocin for activation of CMC to control the dangerous food-borne pathogen, Listeria monocytogenes. Minced beef samples were inoculated with L. monocytogenes ATCC BAA-679 and treated with plantaricin W-activated food packaging. The results showed a significant reduction of the target pathogen by approximately 1 log cycle compared to the control group. Enterocin F4-9 is a novel bacteriocin that acts on Gram-negative microbes that were not affected by plantaricin W. Therefore, a novel food packaging activated with plantaricin W and enterocin F4-9 was developed to broaden their antimicrobial activity. The effect of this film on meat-associated microbes was investigated. The results demonstrated that the film significantly reduced the counts of mesophilic and psychotropic bacteria by 86.67% and 96.67%, respectively. Additionally, the pH values of the treated meat samples were significantly lower than those of the untreated controls. The obtained findings indicated that bacteriocin-activated CMC films could potentially be utilized as antimicrobial packaging in modern food technology. Full article

The rapid growth of world population and increase in living standards have led to an increase in the demand for high-quality, safe food. The Food and Agriculture Organization of the United Nations (FAO) estimates that by 2050 the demand for food will increase by 60%, and production of animal protein will increase by 1.7% a year, with meat production to increase by nearly 70%, dairy products by 55%, and aquaculture by as much as 90%. Microbial contamination of food is a significant problem for the accessibility of safe food which does not pose a threat to the life and health of consumers. Campylobacter, Salmonella, and Yersinia are responsible for thousands of food-borne infections in humans. Currently, numerous programs are being developed to combat pathogenic bacteria in the food supply chain, especially at the primary production stage. These approaches include physical, chemical, biological, and other strategies and methods used to inhibit the bacterial growth of bacteria or completely eliminate the pathogens from the food chain. Therefore, an extremely important goal is to provide safe food and control its quality by eliminating pathogenic and spoilage microorganisms. However, the use of chemicals in food preservation has negative effects for both the consumption values of food and the natural environment. Therefore, it seems absolutely necessary to implement measures utilizing the most environmentally friendly and effective techniques for controlling microbial contamination in food. There is a great need to develop ecological methods in food production which guarantee adequate safety. One of these methods is the use of bacteriophages (bacterial viruses) naturally occurring in the environment. Given the above, the aim of this study was to present the most natural, ecological, and alternative methods of food preservation with regard to the most common foodborne zoonotic bacteria. We also present methods for reducing the occurrence of microbial contamination in food, thus to produce maximally safe food for consumers. Full article

Clostridioides difficile infection (CDI) appears mainly as nosocomial antibiotic-associated diarrhea, and community-acquired infection is increasingly being recognized. The threshold of asymptomatic colonization and the clinical manifestation of CDI need further elucidation. Community-acquired CDI (CA-CDI) should be considered when the disease commences within 48 h of admission to hospital or more than 12 weeks after discharge. Although CDI is not established as a food-borne or zoonotic disease, some data support that direction. The spores’ ability to survive standard cooking procedures and on abiotic surfaces, the formation of biofilms, and their survival within biofilms of other bacteria render even a low number of spores capable of food contamination and spread. Adequate enumeration methods for detecting a low number of spores in food have not been developed. Primary care physicians should take CA-CDI into consideration in the differential diagnosis of diarrhea, as there is a thin line between colonization and infection. In patients diagnosed with inflammatory bowel disease and other comorbidities, C. difficile can be the cause of recurrent disease and should be included in the estimation of diarrhea and worsening colitis symptoms. In the community setting, it is difficult to distinguish asymptomatic carriage from true infection. For asymptomatic carriage, antibiotic therapy is not suggested but contact isolation and hand-washing practices are required. Primary healthcare providers should be vigilant and implement infection control policies for the prevention of C. difficile spread. Full article

As a common food-borne pathogen, Vibrio parahaemolyticus comes into direct or indirect contact with gastric acid after ingestion. However, the mechanisms by which Vibrio parahaemolyticus passes through the gastric acid barrier, recovers, and causes pathogenicity remain unclear. In this study, static in vitro digestion simulation experiments showed that some strains can pass through the gastric acid barrier by utilizing microacid tolerance mechanisms and altering their survival state. Food digestion simulation experiments showed that food matrices could help bacteria escape gastric acid stress, with significantly different survival rates observed for bacteria in various food matrices after exposure to gastric acid. Interestingly, surviving Vibrio parahaemolyticus showed a significantly shorter growth lag time (LT) during recovery. Transcriptome sequencing (RNA-seq) analyses indicated that the bacteria adapted to gastric acid stress by regulating the two-component system through stress proteins secreted via the ribosomal pathway. Pathogenic Vibrio parahaemolyticus that successfully passes through the gastric acid barrier potentially exhibits enhanced pathogenicity during recovery due to the significant upregulation of virulence genes such as tdh and yscF. This study provides a scientific basis for revealing the tolerance mechanisms of food-borne pathogens represented by Vibrio parahaemolyticus in the human body. Full article

Histamine is a biogenic amine found across the phylogenetic spectrum, from plants to fish to animals. In farm animal production, the host’s production of histamine within the intestinal tract serves as a neurotransmitter, facilitating communication from the gut to the brain. Histamine functions additionally as a “bridging” chemical between the immune and nervous systems as it facilitates nervous system modulation of host immune response, thereby playing a critical role in host defense within the gut. Increased histamine levels within the gut, whether originating from food-borne sources or produced in situ, can lead to immune dysregulation and consequent physiological harm. As such, control of histamine within the gut can improve overall gut health across a broad range of species. In the present study, we utilized a Microbial Endocrinology-based approach as a platform technology to enable the discovery of unique histamine-degrading bacteria within the gut microbiota. Broiler chickens were fed, or not, a low or high histamine-supplemented diet from one day of age to up to 42 days in order to encourage the increased abundance of putative histamine-degrading bacteria. Intestinal contents were employed in a discovery protocol that involved repeated isolation rounds utilizing a histamine-supplemented minimal medium. We herein report the discovery that the genus Brevibacterium are capable of up to 100% degradation of histamine in vitro. Feeding experiments utilizing one of the identified Brevibacterium spp., a B. sediminis isolate, demonstrated that it reduced the amount of histamine in the gut of broilers fed a histamine-containing diet and enabled an improvement in growth as compared to non-B. sediminis-supplemented animals. As such, this study demonstrates the usefulness of a Microbial Endocrinology-based approach for the discovery of bacteria that may serve as potential probiotic candidates for the control of neurochemical-mediated interactions within the host, thereby improving host health. Full article

Coagulase-negative bacteria of the Staphylococcus genus are currently frequent food contaminants. The increase in antibiotic resistance means that these microorganisms are becoming the cause of many serious infections and toxications. Their resistance to routinely used chemical compounds has led to the search for alternative methods to combat food-borne pathogens. For this purpose, plant extracts rich in phenolic compounds are increasingly used. The aim of this study was to assess the effect of extracts obtained from the pseudo-fruits and flesh of Rosa canina, Rosa rugosa and Rosa pomifera ‘Karpatia’ on the growth dynamics of bacterial strains of the Staphylococcus genus (72-h co-culture; plate inoculation method). The conducted studies allowed us to conclude that extracts from Rosa spp. show high antistaphylococcal activity. However, it is not proportional to the dose used. Rosa spp. extracts already at concentrations of ¼ MIC limit the growth of the biomass of bacteria of the Staphylococcus genus. The above-described dependencies are very individual—strain-specific, not species-specific. However, based on SEM analysis, it can be observed that the antistaphylococcal mechanism of action of Rosa spp. extracts is associated with the coating of cell walls by the extracts and the disintegration of cell membranes, as a result of which the cells are destroyed. Full article

Farms are a major source of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB), and previous research mainly focuses on polluted soils and breeding environments. However, slaughtering is an important link in the transmission of ARGs and ARB from farmland to dining table. In this study, we aim to reveal the pollution of ARGs and ARB in the slaughter process of broilers. First, by qualitative and quantitative analysis of ARGs in samples collected from the broiler slaughtering and processing production chain, the contamination level of ARGs was reflected; secondly, potential hosts for ARGs and microbial community were analyzed to reflect the possible transmission rules; thirdly, through the antibiotic susceptibility spectrum analysis of four typical food-borne pathogens, the distribution of ARB was revealed. The results showed that 24 types of ARGs were detected positive on the broiler slaughter production line, and tetracycline-resistance genes (20.45%) were the most frequently detected. The types of ARGs vary with sampling process, and all sampling links contain high levels of sul2 and intI1. The most abundant ARGs were detected in chicken surface in the scalding stage and entrails surface in the evisceration stage. There was a significant correlation between intI1 and tetM, suggesting that tetM might be able to enter the human food chain through class-1 integrons. The host range of the oqxB gene is the most extensive, including Sphingobacterium, Bacteroidia unclassified, Rothia, Microbacterium, Algoriella, etc. In the relevant links of the slaughter production line, the microbial community structure is similar. Removing viscera may cause diffusion of ARGs carried by intestinal microorganisms and contaminate chicken and following processing production. The four food-borne pathogens we tested are widely present in all aspects of the slaughter process, and most of them have multi-drug resistance and even have a high degree of resistance to some veterinary drugs banned by the Ministry of Agriculture. Our study preliminarily revealed the pollution of ARGs and ARB in the slaughter process of broilers, and these results are helpful to carry out food safety risk assessment and formulate corresponding control measures. Full article

Escherichia coli (E. coli), especially the Shiga toxin-producing O157:H7 strain, poses severe health risks. In rural Ecuador, raw milk consumption heightens contamination risks. This study analyzed 633 raw milk samples from Pichincha and Manabí to assess E. coli O157:H7 prevalence. The samples were enriched using BHI broth, and then specific culture media were used to isolate E. coli O157:H7. The pathogen in the enriched raw milk was identified, and the isolates were specifically confirmed through the application of a newly designed qPCR assay. The novel qPCR assay demonstrated remarkable sensitivity, capable of detecting up to one copy of genetic material, and specificity (no amplification of other bacteria). An extremely high E. coli O157:H7 prevalence of 0.63 (n = 401) was detected, where the province with the highest number of positive samples was Manabí with 72.8% (n = 225/309) and 54.3% (n = 179/324) for Pichincha. In both provinces, the presence of E. coli O157:H7 contamination exhibited a favorable correlation with small-scale farms and elevated temperatures. This research provides valuable data on the microbiological contamination of E. coli O157:H7 present in raw milk, in addition to an improved method that has been demonstrated to be faster, more sensitive, and more specific than conventional and previously published methods, highlighting the associated risk of food-borne infections and pointing out potential shortcomings in the regulation of agricultural practices and the need for periodic monitoring of bacterial contamination levels with updated methods. Full article

Background: Fresh produce such as leafy green salads have recently become recognized as a potential source of food-borne infection by enteric pathogens This study investigated whether compounds released from damaged salad leaves were recognized by Listeria monocytogenes strain EGD and if they impacted its growth and virulence. Methods: The effects of extracts of salad leaves or salad bag fluids were tested on the growth, biofilm formation, and colonization of salad leaves and host cell virulence. Results: The presence of salad extract at a concentration of less than 0.5% v/v and salad bag fluids at a concentration of 10% v/v enhanced the growth in water and serum-based medium by more than 10,000 times over un-supplemented control cultures. Light and scanning electron microscopy, as well as eukaryotic Caco-2 and Galleria mellonella models of infection, showed that leafy green extracts from rocket, lettuce, spinach, and their salad bag fluids significantly increased the ability of Listeria to establish biofilms and infect host cells. Conclusions: This investigation showed that salad leaf extracts can markedly enhance bacterial virulence, which has implications for bagged salad leaf consumer safety if the leaves become contaminated with pathogenic bacteria such as Listeria. Full article

The drying of insects is an important step in their processing. This research aimed to investigate the impact of a pulsed electric field (PEF), immersion in ethanol (EtOH), and combined (immersion in EtOH followed by PEF) treatment on the convective drying process, the emission of CO_2, and the quality of the dried insects with regard to such elements as water content and activity, rehydration and hygroscopic properties, optical properties, internal structure, and microbiological quality. In applying a PEF, the drying time was made longer (up to 21%), but the rehydration and hygroscopic properties were improved (about 15–16.5% and 8.3–21.7%, respectively) compared to the untreated sample. Using a PEF prior to EtOH treatment improved the rehydration properties (about 3.9–5.9%), while the hygroscopicity was slightly lower compared to the PEF-treated samples. Furthermore, immersion in ethanol (both alone and after PEF) provided a lighter color of dried insects and more outstanding microbiological quality, e.g., the absence of water-borne and food-borne pathogens and anaerobic spore-forming bacteria. This study revealed that combined pretreatment seems to be the most promising method for insects as regards obtaining better rehydration and comparable hygroscopic properties, as well as an attractive color compared to untreated insects, and, above all, in ensuring suitable microbiological quality. Full article

Thyme essential oils (EOs) have antioxidant, antiviral, antifungal, antibacterial, anti-inflammatory, and immunological properties and are used in medicine, food, feed additives, and cosmetics. Here, we made use of a multidimensional analytical method to analyze the differences in the chemical components, chemotypes, and antioxidant and antibacterial activities of EOs from 24 Chinese native thymes. These Chinese native thymes comprised 10 species (Thymus quinquecostatus, T. mongolicus, T. inaequalis, T. mandschuricus, T. curtus, T. amurensis, T. roseus, T. proximu, T. marschallianus, and T. altaicus) and two varieties (T. quinquecostatus var. asiaticus and T. quinquecostatus var. przewalskii). Four primary chemotype groups were identified, namely carvacrol, thymol, geraniol, and α-terpineol. The maximum carvacrol, thymol, geraniol, and α-terpineol contents were 72.4, 58.6, 59.5, and 65.4%, respectively. The antioxidant capacities of the thymol and carvacrol chemotype EOs were found to be significantly superior to the other chemotypes using three antioxidant assays: DPPH, ABTS, and FRAP. Moreover, the thymol and carvacrol EO chemotypes could significantly inhibit the growths of the common food-borne pathogenic bacteria Staphylococcus aureus and Escherichia coli. A correlation analysis between the EO components and the bacteria showed that thymol significantly positively correlated with the bacteria. In summary, we analyzed the thyme EOs’ antioxidant and antibacterial activities, which laid a foundation for their use in medicines, foods, feed additives, and cosmetics. The results will also be very useful for the selection of wild thymes for functional research on carvacrol-, thymol-, geraniol-, and α-terpineol-rich essential oil chemotypes and the product development of feed additives, cosmetics, etc. Full article

The irrational use of antimicrobials has led to the emergence of resistance, impacting not only pathogenic bacteria but also commensal bacteria. Resistance against colistin, a last-resort antibiotic, mediated by globally disseminated plasmid-borne mobile colistin resistance (mcr) genes, has raised significant global concerns. This cross-sectional study aimed to investigate the antimicrobial resistance patterns of colistin-resistant Escherichia coli (E. coli) and mobilised colistin resistance (mcr 1–5) genes from broiler meat. A total of 570 broiler samples (285 liver and 285 muscle) were collected from 7 supermarkets and 11 live bird markets (LBMs) in Chattogram metropolitan areas of Bangladesh. The isolation and identification of E. coli were carried out using standard bacteriological and molecular techniques. Antimicrobial susceptibility testing (AST) was performed using the Kirby–Bauer disc diffusion method, and colistin’s minimum inhibitory concentration (MIC) was determined by the broth microdilution (BMD) method. Colistin-resistant isolates were further tested for the presence of mcr (1–5) genes using polymerase chain reaction (PCR). Out of the 570 samples, 311 (54.56%; 95% confidence interval: 50.46–58.60) were positive for E. coli. AST results showed the highest resistance to sulphamethoxazole–trimethoprim (89.39%), while the highest susceptibility was observed for cefalexin (62.70%). A total of 296 isolates (95.18%) were found to be multidrug-resistant (MDR), with the multiple antibiotic resistance (MAR) index ranging from 0.38 to 1. Additionally, 41 isolates (13.18%) exhibited resistance to five antimicrobial classes, with resistance patterns of CIP + SXT + AMP + DO + TE + CT. A total of 233 isolates (74.92%) were resistant to colistin (MIC > 2 mg/L). A strong correlation between colistin resistance and the presence of the mcr-1 gene was observed (r = 1). All phenotypic colistin-resistant E. coli isolates carried the mcr-1 gene, while no isolates were positive for mcr (2–5). The detection of mcr genes in E. coli strains from poultry sources poses a significant risk, as these resistance genes can be transferred to humans through the food chain. The prevalence of multidrug-resistant Escherichia coli and the mcr-1 gene in poultry products in Bangladesh presents a significant public health and food safety concern. Full article

Arcobacter-related species are considered emerging food-borne and waterborne pathogens, with shellfish being a suggested reservoir. In a published study that investigated 204 shellfish samples and 476 isolates, the species Arcobacter butzleri (now known as Aliarcobacter butzleri) and Arcobacter molluscorum (now known as Malaciobacter molluscorum) have been isolated as the most dominant species. However, the efficiency of depuration for eliminating A. butzleri and M. molluscorum in comparison with Escherichia coli from mussels and oysters is unknown and is therefore the objective of this investigation. The shellfish depuration process was evaluated in the laboratory, in summer and winter, using mussels and oysters collected from the Ebro Delta harvesting areas after performing a natural contamination and an artificial contamination using the same conditions for both mollusk and seasons. The natural contamination was performed by exposing the shellfish to a freshwater channel that receives untreated sewage from the village of Poble Nou (PNC) and that had a salinity of 10.7–16.8‰. The artificial contamination exposed the shellfish to A. butzleri and E. coli (in one tank) and to M. molluscorum and E. coli in another tank under controlled conditions of salinity (34.5‰) and temperature (20 °C summer and 14 °C winter). When evaluating the reduction in the bacteria load (every 24 h) throughout 120 h, the naturally contaminated shellfish at the PNC showed a higher reduction than the shellfish contaminated at the laboratory, with the exception of M. molluscorum, that at 24 h could not be detected in summer, neither in mussels nor in oysters. This may be attributed to the fact that the bacteria from the PNC were less adapted to the conditions of high salinity (34.5‰) in which the depuration process was performed. Although temperature did not statistically make a difference in depuration, at 20 °C a higher elimination of all bacteria was recorded relative to 14 °C. In general, E. coli survived more in mussels than in oysters, and M. molluscorum suffered in both mollusks a higher reduction than A. butzleri. New studies are required to determine further the safety of bivalves regarding the presence of Arcobacter-related species. Full article

Banana is an important fruit and food crop in tropical and subtropical regions worldwide. Banana production is seriously threatened by Fusarium wilt of banana (FWB), a disease caused by Fusarium oxysporum f. sp. cubense, and biological control is an important means of curbing this soil-borne disease. To reveal the effects of biocontrol agents on inhibiting FWB and altering the soil bacterial community under natural ecosystems, we conducted experiments at a banana plantation. The control efficiency of a compound microbial agent (CM), Paenibacillus polymyxa (PP), Trichoderma harzianum (TH), and carbendazim (CA) on this disease were compared in the field. Meanwhile, the alterations in structure and function of the rooted soil bacterial community in different treatments during the vigorous growth and fruit development stages of banana were analyzed by microbiomics method. The results confirmed that the different biocontrol agents could effectively control FWB. In particular, CM significantly reduced the incidence of the disease and showed a field control efficiency of 60.53%. In terms of bacterial community, there were no significant differences in the richness and diversity of banana rooted soil bacteria among the different treatments at either growth stage, but their relative abundances differed substantially. CM treatment significantly increased the ratios of Bacillus, Bryobacter, Pseudomonas, Jatrophihabitans, Hathewaya, and Chujaibacter in the vigorous growth stage and Jatrophihabitans, Occallatibacter, Cupriavidus, and 1921-3 in the fruit development stage. Furthermore, bacterial community function in the banana rooted soil was affected differently by the various biocontrol agents. CM application increased the relative abundance of multiple soil bacterial functions, including carbohydrate metabolism, xenobiotic biodegradation and metabolism, terpenoid and polyketide metabolism, lipid metabolism, and metabolism of other amino acids. In summary, our results suggest that the tested biocontrol agents can effectively inhibit the occurrence of banana Fusarium wilt and alter the soil bacterial community in the field. They mainly modified the relative abundance of bacterial taxa and the metabolic functions rather than the richness and diversity. These findings provide a scientific basis for the use of biocontrol agents to control banana Fusarium wilt under field conditions, which serves as a reference for the study of the soil microbiological mechanisms of other biocontrol agents. Full article

Wine production is one of the most important agricultural activities. The winemaking process generates a considerable volume of different residues characterized as by-products, such as pomace, seeds, stems, and skins. By-products are rich in polyphenols with antioxidant and antibacterial properties and may act as bacteriostatic or bactericidal agents against food-borne pathogens, improving food safety by enhancing antibiotic efficacy and reducing bacterial resistance. The aim of this study was to evaluate the phenolic composition and antioxidant activity of grape components (skins, seeds, and stems) from three red grape varieties (Periquita, Gamay, and Donzelinho Tinto) and determine their antibacterial activity against antibiotic-resistant bacteria, including Escherichia coli in food-producing animals and Listeria monocytogenes from food products and food-related environments. Ten phenolic compounds were quantified in these red grape varieties, with specific compounds found in different parts of the grape, including phenolic acids and flavonoids. Flavonoids are abundant in seeds and stems, malvidin-3-O-glucoside being the main anthocyanin in skins. The ethanolic extract from the seeds showed in vitro concentration-dependent activity against reactive species like ^•NO and O₂^•−. Gamay extract was the most effective, followed by Donzelinho Tinto and Periquita. Extracts showed varying antibacterial activity against Gram-positive and Gram-negative bacteria, with stronger effects on Gram-positive bacteria. L. monocytogenes was more susceptible, while E. coli was limited to three strains. Seeds exhibited the strongest antibacterial activity, followed by stems. The results of our study provide evidence of the potential of grape by-products, particularly seeds, as sources of bioactive compounds with antioxidant and antibacterial properties, offering promising avenues for enhancing food safety and combating antibiotic resistance in food production and related environments. Full article