Using GWAS and Machine Learning to Identify and Predict Genetic Variants Associated with Foodborne Bacteria Phenotypic Traits.

One of the main challenges in food microbiology is to prevent the risk of outbreaks by avoiding the distribution of food contaminated by bacteria. This requires constant monitoring of the circulating strains throughout the food production chain. Bacterial genomes contain signatures of natural evolution and adaptive markers that can be exploited to better understand the behavior of pathogen in the food industry. The monitoring of foodborne strains can therefore be facilitated by the use of these genomic markers capable of rapidly providing essential information on isolated strains, such as the source of contamination, risk of illness, potential for biofilm formation, and tolerance or resistance to biocides. The increasing availability of large genome datasets is enhancing the understanding of the genetic basis of complex traits such as host adaptation, virulence, and persistence. Genome-wide association studies have shown very promising results in the discovery of genomic markers that can be integrated into rapid detection tools. In addition, machine learning has successfully predicted phenotypes and classified important traits. Genome-wide association and machine learning tools have therefore the potential to support decision-making circuits intending at reducing the burden of foodborne diseases. The aim of this chapter review is to provide knowledge on the use of these two methods in food microbiology and to recommend their use in the field.

Hybrid recognition-enabled ratiometric electrochemical sensing of Staphylococcus aureus via in-situ growth of MOF/Ti3C2Tx-MXene and a self-reporting bacterial imprinted polymer.

Rapid and effective analysis of foodborne bacteria is crucial for preventing and controlling bacterial infections. Here, we present the synthesis of a self-reporting molecularly imprinted polymer (MIP) as an inner reference probe (IR), and the in-situ growth of metal-organic frameworks on transition metal carbon nitrides (MOF/Ti3C2TX-MXene) as a signaling nanoprobe (SP). These advancements are then applied in a ratiometric electrochemical bioassay for Staphylococcus aureus (S. aureus) using a hybrid recognition mechanism. When S. aureus is present, the aptamer-integrated MIP (MIP@Apt) efficiently captures it, followed by binding with SP to form a sandwich structure. This leads to decreased current response of IR (IIR) and increased current intensity of SP (Isp), enabling quantification through utilization of the ISP to IIR ratio. The biosensor shows a wide detection range (10-108 CFU mL-1) and low detection limit of 1.2 CFU mL-1. Its feasibility for testing complex samples indicates the potential application in food analysis.

Antimicrobial resistance in food-borne pathogens at the human-animal interface: Results from a large surveillance study in India.

Background: The burden of foodborne diseases and antimicrobial resistance carried by key foodborne pathogens in India is unknown due to a lack of an integrated surveillance system at the human-animal interface. Methods: We present data from the WHO-AGISAR (Advisory Group on Integrated Surveillance of Antimicrobial Resistance), India project. Concurrent human and animal sampling was done across a large area across north India. Community-acquired diarrhea cases (n = 1968) of all age groups were included. Cross-sectional sampling of stool/ intestinal contents (n = 487) and meat samples (n = 419) from food-producing animals was done at farms, retail shops, and slaughterhouses. Pathogens were cultured and identified, and antimicrobial susceptibility was performed. Results: Over 80% of diarrhoeal samples were obtained from moderate to severe diarrhea patients, which yielded EAEC (5%), ETEC (4.84%), EPEC (4.32%), and Campylobacter spp. (2%). A high carriage of EPEC (32.11%) and Campylobacter spp. (24.72%) was noted in food animals, but the prevalence of ETEC (2%) and EAEC (1%) was low. Atypical EPEC (aEPEC, 84.52%, p ≤0.0001) were predominant and caused milder diarrhea. All EPEC from animal/poultry were aEPEC. Overall, a very high level of resistance was observed, and the MDR rate ranged from 29.2% in Campylobacter spp., 53.6% in EPEC, and 59.8% in ETEC. Resistance to piperacillin-tazobactam, cefepime, ceftriaxone, and co-trimoxazole was significantly higher in human strains. In contrast, resistance to ciprofloxacin, aminoglycosides, and tetracycline was higher in animal strains, reflecting the corresponding usage in human and animal sectors. ESBL production was commoner in animal isolates than in humans, indicating high use of third-generation cephalosporins in the animal sector. C. hyointestinalis is an emerging zoonotic pathogen, first time reported from India. Conclusion: In one of the most extensive studies from India, a high burden of key foodborne pathogens with MDR and ESBL phenotypes was found in livestock, poultry, and retail meat.

Comprehensive analysis of predominant pathogenic bacteria and viruses in seafood products.

Given the growing global demand for seafood, it is imperative to conduct a comprehensive study on the prevalence and persistence patterns of pathogenic bacteria and viruses associated with specific seafood varieties. This assessment thoroughly examines the safety of seafood products, considering the diverse processing methods employed in the industry. The importance of understanding the behavior of foodborne pathogens, such as Salmonella typhimurium, Vibrio parahaemolyticus, Clostridium botulinum, Listeria monocytogenes, human norovirus, and hepatitis A virus, is emphasized by recent cases of gastroenteritis outbreaks linked to contaminated seafood. This analysis examines outbreaks linked to seafood in the United States and globally, with a particular emphasis on the health concerns posed by pathogenic bacteria and viruses to consumers. Ensuring the safety of seafood is crucial since it directly relates to consumer preferences on sustainability, food safety, provenance, and availability. The review focuses on assessing the frequency, growth, and durability of infections that arise during the processing of seafood. It utilizes next-generation sequencing to identify the bacteria responsible for these illnesses. Additionally, it analyzes methods for preventing and intervening of infections while also considering the forthcoming challenges in ensuring the microbiological safety of seafood products. This evaluation emphasizes the significance of the seafood processing industry in promptly responding to evolving consumer preferences by offering current information on seafood hazards and future consumption patterns. To ensure the continuous safety and sustainable future of seafood products, it is crucial to identify and address possible threats.

Essential Oil Emulsion from Caper (Capparis spinosa L.) Leaves: Exploration of Its Antibacterial and Antioxidant Properties for Possible Application as a Natural Food Preservative.

This study explored, for the first time, the chemical composition and in vitro antioxidant and antibacterial activities of a caper leaf essential oil (EO) emulsion for possible food applications as a natural preservative. The EO was extracted by hydrodistillation from the leaves of Capparis spinosa growing wild in the Aeolian Archipelago (Sicily, Italy) and exhibited a pungent, sulphurous odour. The volatile fraction of the emulsion, analysed by SPME-GC-MS, consisted of over 100 compounds and was dominated by compounds with recognised antibacterial and antioxidant properties, namely dimethyl tetrasulfide (18.41%), dimethyl trisulfide (12.58%), methyl isothiocyanate (7.97%), and terpinen-4-ol (6.76%). The emulsion was effective against all bacterial strains tested (Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enterica subsp. enterica serovar Enteritidis, Pseudomonas fluorescens), with L. monocytogenes exhibiting the lowest minimum inhibitory concentration (MIC = 0.02 mg/mL) while E. coli had the highest (MIC = 0.06 mg/mL). The emulsion had a good DPPH (2,2-diphenyl-1-picrylhydrazine) radical scavenging activity that was dose-dependent and equal to 42.98% at the 0.08 mg/mL level with an IC50 value of 0.099 mg/mL. Based on the results, the caper leaf EO emulsion has the potential to be proposed as a natural alternative to chemical preservatives in the food industry.

Prevalence and Antimicrobial Resistance of Listeria monocytogenes in Different Raw Food from Reynosa, Tamaulipas, Mexico.

Listeria (L.) monocytogenes is an opportunistic foodborne pathogen that causes listeriosis in humans and animals, reaching up to 30% case mortality. There are only a few reports in Mexico about the L. monocytogenes strains found in various foods. The aim of this study was to determine the prevalence of L. monocytogenes, serogroups, virulence genes, and antimicrobial resistance in different foods from Reynosa, Tamaulipas, Mexico. L. monocytogenes strains were characterized by microbiological and molecular methods. Susceptibility to 12 antibiotics was determined according to CLSI and EUCAST. A total of 300 samples of seafood, pasteurized and raw milk, cheese, beef, and chicken were collected from supermarkets and retail markets. The presence of L. monocytogenes was detected in 5.6% of the samples. Most strains belonged to serogroups 4b, 4d, and 4e (68.4%). All strains presented a minimum of four virulence genes; the most common were actA, hly, and plcB (92.1%). A high percentage of antimicrobial susceptibility was observed, with resistance only to STX-TMP (78.9%), STR (26.3%), MEM (21.0%), and E (2.6%). These results show that the foods in Reynosa, Tamaulipas, are a reservoir of L. monocytogenes and represent a potential health risk.

Analysis of Antimicrobial Resistance in Bacterial Pathogens Recovered from Food and Human Sources: Insights from 639,087 Bacterial Whole-Genome Sequences in the NCBI Pathogen Detection Database.

Understanding the role of foods in the emergence and spread of antimicrobial resistance necessitates the initial documentation of antibiotic resistance genes within bacterial species found in foods. Here, the NCBI Pathogen Detection database was used to query antimicrobial resistance gene prevalence in foodborne and human clinical bacterial isolates. Of the 1,843,630 sequence entries, 639,087 (34.7%) were assigned to foodborne or human clinical sources with 147,788 (23.14%) from food and 427,614 (76.88%) from humans. The majority of foodborne isolates were either Salmonella (47.88%), Campylobacter (23.03%), Escherichia (11.79%), or Listeria (11.3%), and the remaining 6% belonged to 20 other genera. Most foodborne isolates were from meat/poultry (95,251 or 64.45%), followed by multi-product mixed food sources (29,892 or 20.23%) and fish/seafood (6503 or 4.4%); however, the most prominent isolation source varied depending on the genus/species. Resistance gene carriage also varied depending on isolation source and genus/species. Of note, Klebsiella pneumoniae and Enterobacter spp. carried larger proportions of the quinolone resistance gene qnrS and some clinically relevant beta-lactam resistance genes in comparison to Salmonella and Escherichia coli. The prevalence of mec in S. aureus did not significantly differ between meat/poultry and multi-product sources relative to clinical sources, whereas this resistance was rare in isolates from dairy sources. The proportion of biocide resistance in Bacillus and Escherichia was significantly higher in clinical isolates compared to many foodborne sources but significantly lower in clinical Listeria compared to foodborne Listeria. This work exposes the gaps in current publicly available sequence data repositories, which are largely composed of clinical isolates and are biased towards specific highly abundant pathogenic species. We also highlight the importance of requiring and curating metadata on sequence submission to not only ensure correct information and data interpretation but also foster efficient analysis, sharing, and collaboration. To effectively monitor resistance carriage in food production, additional work on sequencing and characterizing AMR carriage in common commensal foodborne bacteria is critical.

Vine-Winery Byproducts as Precious Resource of Natural Antimicrobials: In Vitro Antibacterial and Antibiofilm Activity of Grape Pomace Extracts against Foodborne Pathogens.

Grape pomace is the main by-product of vine-winery chains. It requires adequate treatment and disposal but is also an economically underused source of bioactive plant secondary metabolites. This study aimed to investigate the antibacterial effects of polyphenolic extracts from Aglianico (Vitis vinifera L.) grape pomace. In particular, hydroethanolic extracts obtained via an ultrasonic-assisted extraction technique were selected for antimicrobial tests. The extracts were screened for their antibacterial effects against foodborne pathogens that were both Gram-positive, in the case of Staphylococcus aureus and Bacillus cereus, and Gram-negative, in the case of Escherichia coli and Salmonella enterica subsp. enterica serovar Typhimurium, showing variable bacteriostatic and bactericidal effects. In addition, our results demonstrated that the tested grape pomace extracts can reduce the inhibitory concentration of standard antibiotics. Interestingly, selected extracts inhibited biofilm development by S. aureus and B. cereus. Overall, these new insights into the antibacterial properties of grape pomace extracts may represent a relevant step in the design of novel therapeutic tools to tackle foodborne diseases, and in the management of resistant biofilm-related infections.

Assessing the difference in contamination of retail meat with multidrug-resistant bacteria using for-consumer package label claims that indicate on-farm antibiotic use practices- United States, 2016-2019.

BACKGROUND: Antibiotic use in food-producing animals can select for antibiotic resistance in bacteria that can be transmitted to people through contamination of food products during meat processing. Contamination resulting in foodborne illness contributes to adverse health outcomes. Some livestock producers have implemented antibiotic use reduction strategies marketed to consumers on regulated retail meat packaging labels ("label claims"). OBJECTIVE: We investigated whether retail meat label claims were associated with isolation of multidrug-resistant organisms (MDROs, resistant to ≥3 classes of antibiotics) from U.S. meat samples. METHODS: We utilized retail meat data from the U.S. Food and Drug Administration National Antimicrobial Resistance Monitoring System (NARMS) collected during 2016-2019 for bacterial contamination of chicken breast, ground turkey, ground beef, and pork chops. We used modified Poisson regression models to compare the prevalence of MDRO contamination among meat samples with any antibiotic restriction label claims versus those without such claims (i.e., conventionally produced). RESULTS: In NARMS, 62,338 meat samples were evaluated for bacterial growth from 2016-2019. Of these, 24,446 (39%) samples had label claims that indicated antibiotic use was restricted during animal production. MDROs were isolated from 2252 (4%) meat samples, of which 71% (n = 1591) were conventionally produced, and 29% (n = 661) had antibiotic restriction label claims. Compared with conventional samples, meat with antibiotic restriction label claims had a statistically lower prevalence of MDROs (adjusted prevalence ratio: 0.66; 95% CI: 0.61, 0.73). This relationship was consistent for the outcome of any bacterial growth. IMPACT: This repeated cross-sectional analysis of a nationally representative retail meat surveillance database in the United States supports that retail meats labeled with antibiotic restriction claims were less likely to be contaminated with MDROs compared with retail meat without such claims during 2016-2019. These findings indicate the potential for the public to become exposed to bacterial pathogens via retail meat and emphasizes a possibility that consumers could reduce their exposure to environmental reservoirs of foodborne pathogens that are resistant to antibiotics.

Bioactivity of Microencapsulated Cell-Free Supernatant of Streptococcus thermophilus in Combination with Thyme Extract on Food-Related Bacteria.

The bioactive properties of the combination of microencapsulated cell-free supernatant (CFS) from Streptococcus thermophilus and thyme extract on food-related bacteria (Photobacterium damselae, Proteus mirabilis, Vibrio vulnificus, Staphylococcus aureus ATCC29213, Enterococcus faecalis ATCC29212, and Salmonella Paratyphi A NCTC13) were investigated. The microencapsulated CFS of S. thermophilus, in combination with ethanolic thyme extract, had a particle size in the range of 1.11 to 11.39 µm. The microencapsulated CFS of S. thermophilus had a wrinkled, spherical form. In the supernatant, especially at 2% (v/w), the thyme extract additive caused a decrease in the wrinkled form and a completely spherical structure. A total of 11 compounds were determined in the cell-free supernatant of S. thermophilus, and acetic acid (39.64%) and methyl-d3 1-dideuterio-2-propenyl ether (10.87%) were the main components. Thyme extract contained seven components, the main component being carvacrol at 67.96% and 1,2,3-propanetriol at 25.77%. Significant differences (p < 0.05) were observed in the inhibition zones of the extracts on bacteria. The inhibitory effect of thyme extract on bacteria varied between 25.00 (P. damselae) and 41.67 mm (V. vulnificus). Less antibacterial activity was shown by the microencapsulated CFS from S. thermophilus compared to their pure form. (p < 0.05). As a result, it was found that microencapsulated forms of CFS from S. thermophilus, especially those prepared in combination with 2% (v/w) thyme extract, generally showed higher bioactive effects on bacteria.

Nucleic acid strand displacement for indirect determination of foodborne bacteria by capillary electrophoresis and its application in antagonism and bacteriostasis studies.

Foodborne bacteria threaten human's health. Capillary electrophoresis (CE) is a powerful separation means for the determination of bacteria. Direct separation of bacteria suffers from the shortages of low resolution, channel adsorption, and bacterial aggregation. In this work, a method of nucleic acid strand displacement was developed to indirect separate the bacteria by CE. DNA complexes, consisting of probes and aptamers, were mixed with the three bacteria Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The aptamers could specifically bond with bacteria and release the probes. Through the separation of the probes, the bacteria could be indirectly determined by CE. This method avoided the shortages of direct separation of bacteria. Under the optimized conditions, the three probes for the bacteria could be separated and detected within 2.5 min by high-speed CE with laser-induced fluorescence detection. The limits of detection for the bacteria were in the range 4.20 × 106 to 1.75 × 107  CFU/mL. Finally, the developed method was applied on the study of antagonism of the coexistent bacteria to reveal the relationship between them. Furthermore, the efficiency of bacteriostasis of three traditional Chinese medicines, Coptis chinensis, Schisandra chinensis, and honeysuckle, was also studied by this method.

The Primary Mode of Action of Lippia graveolens Essential Oil on Salmonella enterica subsp. Enterica Serovar Typhimurium.

Essential oils are known to exhibit diverse antimicrobial properties, showing their value as a natural resource. Our work aimed to investigate the primary mode of action of Cuban Lippia graveolens (Kunth) essential oil (EO) against Salmonella enterica subsp. enterica serovar Typhimurium (S. enterica ser. Typhimurium). We assessed cell integrity through various assays, including time-kill bacteriolysis, loss of cell material with absorption at 260 and 280 nm, total protein leakage, and transmission electron microscopy (TEM). The impact of L. graveolens EO on membrane depolarization was monitored and levels of intracellular and extracellular ATP were measured by fluorescence intensity. The minimum inhibitory and bactericidal concentrations (MIC and MBC) of L. graveolens EO were 0.4 and 0.8 mg/mL, respectively. This EO exhibited notable bactericidal effects on treated cells within 15 min without lysis or leakage of cellular material. TEM showed distinct alterations in cellular ultrastructure, including membrane shrinkage and cytoplasmic content redistribution. We also observed disruption of the membrane potential along with reduced intracellular and extracellular ATP concentrations. These findings show that L. graveolens EO induces the death of S. enterica ser. Typhimurium, important information that can be used to combat this foodborne disease-causing agent.

Triazine-based covalent-organic framework embedded with cuprous oxide as the bioplatform for photoelectrochemical aptasensing Escherichia coli.

A superior photoelectrochemical (PEC) aptasensor was manufactured for the detection of Escherichia coli (E. coli) based on a hybrid of triazine-based covalent-organic framework (COF) and cuprous oxide (Cu2O). The COF synthesized using 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and 1,3,5-triformylphloroglucinol (Tp) as building blocks acted as a scaffold for encapsulated Cu2O nanoparticles (denoted as Cu2O@TAPB-Tp-COF), which then was employed as the bioplatform for anchoring E. coli-targeted aptamer. Cu2O@Cu@TAPB-Tp-COF demonstrated enhanced separation of the photogenerated carriers and photoabsorption ability and boosted photoelectric conversion efficiency. The developed Cu2O@TAPB-Tp-COF-based PEC aptasensor exhibited a lower detection limit of 2.5 CFU mL-1 toward E. coli within a wider range of 10 CFU mL-1 to 1 × 104 CFU mL-1 than most of reported aptasensors for determining foodborne bacteria, together with high selectivity, good stability, and superior ability and reproducibility. The recoveries of E. coli spiked into milk and bread samples ranged within 95.3-103.6% and 96.6-102.8%, accompanying with low RSDs of 1.37-4.48% and 1.74-3.66%, respectively. The present study shows a promising alternative for the sensitive detection of foodborne bacteria from complex foodstuffs and pathogenic bacteria-polluted environment.

Environmental Monitoring of Food Manufacturing Facilities for Listeria: A Case Study.

Environmental monitoring programs (EMPs) for food production facilities are useful for verifying general sanitation controls and are recommended as verification measures to ensure that the Hazard Analysis Critical Control Point plan is working effectively. In this study, EMPs for Listeria were conducted at three food production facilities to assess the efficacy of sanitation control and establish effective sanitation control methods. In Facility A, L. monocytogenes was detected in the clean area although in Zone 3, non-food-contact surfaces. To prevent contamination from dirty areas, the cleaning practices in the preparation room were investigated. Normal cleaning combined with disinfection with carbonated hypochlorite water (chlorine concentration, 150 ppm) proved effective. At Facility B, a salad product and its ingredients (pastrami and salami) were positive for L. monocytogenes serotype 3b. The bacterial count was <10/g in all samples. However, when inoculated with L. monocytogenes isolates, the growth of approximately 2 log cfu/g was observed on pastrami after 48 h of incubation at 10°C. The ingredients were commercially purchased blocks that were sliced in a slicer at Facility B and used as salad toppings. Because both unopened blocks were negative for L. monocytogenes, contamination of the slicer was suspected. Sampling of the slicer revealed that contamination by L. monocytogenes serotype 3b was more extensive after use than before use. Therefore, the slicer was disassembled, cleaned, and disinfected thoroughly. In Facility C, L. monocytogenes serotype 4b (4e) was detected in all the dirty, semiclean, and clean areas. The strain was also isolated from the wheels of a smoking cart transported across the zones. Therefore, efforts were made to frequently clean and disinfect the cart. EMPs revealed the presence of Listeria in each facility and allowed remedial measures to be undertaken. Continued monitoring and Plan-Do-Check-Act cycles were considered desirable.

Rapid and Online Detection of Foodborne Bacteria via a Novel Ultraviolet Photoionization Time-of-Flight Mass Spectrometry.

Foodborne bacteria are widespread contaminated sources of food; hence, the real-time monitoring of pathogenic bacteria in food production is important for the food industry. In this study, a novel rapid detection method based on microbial volatile organic compounds (MVOCs) emitted from foodborne bacteria was established by using ultraviolet photoionization time-of-flight mass spectrometry (UVP-TOF-MS). The results showed obvious differences of MVOCs among the five species of bacteria, and the characteristic MVOCs for each bacterium were selected by a feature selection algorithm. Online monitoring of MVOCs during bacterial growth displayed distinct metabolomic patterns of the five species. MVOCs were most abundant and varied among species during the logarithmic phase. Finally, MVOC production by bacteria in different food matrixes was explored. The machine learning models for bacteria cultured in different matrixes showed a good classification performance for the five species with an accuracy of over 0.95. This work based on MVOC analysis by online UVP-TOF-MS achieved effective rapid detection of bacteria and showed its great application potential in the food industry for bacterial monitoring.

Commonly Consumed Vegetables as a Potential Source of Multidrug-Resistant and ß-Lactamase-Producing Bacteria in Debre Berhan Town, Ethiopia.

Background: Recently, antibiotic resistance of bacteria contained in foods such as vegetables has become a public health problem. In Ethiopia, the diversity of bacterial contamination and level of antibiotic resistance in vegetables are poorly understood. Local analysis of vegetable contamination and its contribution to the spread of antibiotic resistance are therefore essential for One Health interventions. Therefore, the aim of this study was to investigate the level of bacterial contamination of commonly consumed vegetables and their antimicrobial resistance patterns. Methods: A cross-sectional research was conducted in Debre Berhan town from February to August 2022. Questionnaires were used to collect data on sociodemographic variables, hygiene practices, and market hygiene. Six carefully selected vegetables (30 each, 180 in total) were purchased at a local market. Bacterial isolation and identification, multidrug-resistant (MDR) screening and confirmation, extended-spectrum ß-lactamase (ESBL) screening and confirmation, and antibiotic susceptibility tests were performed using standard operating procedure. The data were analysed statistically using SPSS software version 25. Results: The contamination rate of vegetables was 119 (66.1%). Of the 176 bacteria isolates, E. coli (26.1%; 46/176), S. aureus (18.8%; 176), S. epidermidis (10.8%; 19/176), Klebsiella spp. (9.1%; 16/179) and Acinetobacter spp. (6.8%; 12/176) were the most frequently detected isolates. Of the 180 samples tested, (66.1%; 119/180) were contaminated with at least one type of bacteria. Lettuce (22.7%; 40/176), spinach (18.6%; 33/176), and cabbage (19.2%; 32/176) were the most contaminated vegetables. Of the 176 bacteria isolates, (64.8%; 114/176) were MDR, and (18.5%; 23/124) isolates were ESBL producers. The kind of vegetables, vendor/seller finger-nail status, medium of display, market type, and not cleaned before to display were all significantly associated with bacterial contamination. Conclusion: This study found that commonly consumed vegetables are contaminated with antibiotic-resistant bacteria. Vegetables were also notable for the incidence of multidrug-resistant, extended ß-lactamase-resistant, and methicillin-resistant bacterial isolates. Therefore, we urge local health authorities to develop and implement effective control strategies to reduce vegetable contamination.

Salmonella typhimurium detection and ablation using OmpD specific aptamer with non-magnetic and magnetic graphene oxide.

Foodborne diseases have increased in the last few years due to the increased consumption of packaged and contaminated food. Major foodborne bacteria cause diseases such as diarrhea, vomiting, and sometimes death. So, there is a need for early detection of foodborne bacteria as pre-existing detection techniques are time-taking and tedious. Aptamer has gained interest due to its high stability, specificity, and sensitivity. Here, aptamer has been developed against Salmonella Typhimurium through the Cell-Selex method, and to further find the reason for specificity and sensitivity, OmpD protein was isolated, and binding studies were done. Single molecular FRET experiment using aptamer and graphene oxide studies has also been done to understand the mechanism of FRET and subsequently used for target bacterial detection. Using this assay, Salmonella Typhimurium can be detected up to 10 CFU/mL. Further, Magnetic Graphene oxide was used to develop an assay to separate and ablate bacteria using 808 nm NIR where temperature increase was more than 60 °C within 30 s and has been shown by plating as well as a confocal live dead assay. Thus, using various techniques, bacteria can be detected and ablated using specific aptamer and Graphene oxide.

Facile Synthesis, Characterization, and Antimicrobial Assessment of a Silver/Montmorillonite Nanocomposite as an Effective Antiseptic against Foodborne Pathogens for Promising Food Protection.

Foodborne pathogens can have devastating repercussions and significantly threaten public health. Therefore, it is indeed essential to guarantee the sustainability of our food production. Food preservation and storage using nanocomposites is a promising strategy. Accordingly, the present research's objectives were to identify and isolate a few foodborne pathogens from food products, (ii) synthesize and characterize silver nanoparticles (AgNPs) using wet chemical reduction into the lamellar space layer of montmorillonite (MMT), and (iii) investigate the antibacterial potential of the AgNPs/MMT nanocomposite versus isolated strains of bacteria. Six bacterial species, including Escherichia coli, Salmonella spp., Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus were isolated from some food products (meat, fish, cheese, and vegetables). The Ag/MMT nanocomposite was synthesized and characterized using UV-visible spectroscopy, transmission electron microscopy, particle size analyzer, zeta potential, X-ray diffraction (XRD), and scanning electron microscopy with dispersive energy X-ray (EDX). The antibacterial effectiveness of the AgNPs/MMT nanocomposite further investigated distinct bacterial species using a zone of inhibition assay and microtiter-based methods. Nanoparticles with a narrow dimension range of 12 to 30 nm were identified using TEM analysis. The SEM was employed to view the sizeable flakes of the AgNPs/MMT. At 416 nm, the most excellent UV absorption was measured. Four silver metallic diffraction peaks were found in the XRD pattern during the study, and the EDX spectrum revealed a strong signal attributed to Ag nanocrystals. AgNPs/MMT figured out the powerful antibacterial action. The AgNPs/MMT nanocomposite confirmed outstanding minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against six isolates of foodborne pathogens, ranging from 15 to 75 µg/mL, respectively. The AgNPs/MMT's antibacterial potential against gram-negative bacteria was noticeably better than gram-positive bacteria. Therefore, the AgNPs/MMT nanocomposite has the potential to be used as a reliable deactivator in food processing and preservation to protect against foodborne pathogenic bacteria. This suggests that the nanocomposite may be effective at inhibiting the growth and proliferation of harmful bacteria in food, which could help to reduce the risk of foodborne illness.

Utilization of Piper betle L. Extract for Inactivating Foodborne Bacterial Biofilms on Pitted and Smooth Stainless Steel Surfaces.

Biofilms are a significant concern in the food industry. The utilization of plant-derived compounds to inactivate biofilms on food contact surfaces has not been widely reported. Also, the increasing negative perception of consumers against synthetic sanitizers has encouraged the hunt for natural compounds as alternatives. Therefore, in this study we evaluated the antimicrobial activities of ethanol extracts, acetone extracts, and essential oils (EOs) of seven culinary herbs against Salmonella enterica serotype Typhimurium and Listeria innocua using the broth microdilution assay. Among all tested extracts and EOs, the ethanol extract of Piper betle L. exhibited the most efficient antimicrobial activities. To evaluate the biofilm inactivation effect, S. Typhimurium and L. innocua biofilms on pitted and smooth stainless steel (SS) coupons were exposed to P. betle ethanol extract (12.5 mg/ml), sodium hypochlorite (NaClO; 200 ppm), hydrogen peroxide (HP; 1100 ppm), and benzalkonium chloride (BKC; 400 ppm) for 15 min. Results showed that, for the untreated controls, higher sessile cell counts were observed on pitted SS versus smooth SS coupons. Overall, biofilm inactivation efficacies of the tested sanitizers followed the trend of P. betle extract ≥ BKC > NaClO > HP. The surface condition of SS did not affect the biofilm inactivation effect of each tested sanitizer. The contact angle results revealed P. betle ethanol extract could increase the surface wettability of SS coupons. This research suggests P. betle extract might be utilized as an alternative sanitizer in food processing facilities.

Bacteriological Quality and Biotoxin Profile of Ready-to-Eat Foods Vended in Lagos, Nigeria.

A comprehensive study of bacterial and biotoxin contaminants of ready-to-eat (RTE) foods in Nigeria is yet to be reported. Hence, this study applied 16S rRNA gene sequencing and a dilute-and-shoot LC-MS/MS method to profile bacteria and biotoxins, respectively, in 199 RTE food samples comprising eko (n = 30), bread (n = 30), shawarma (n = 35), aadun (n = 35), biscuits (n = 34), and kokoro (n = 35). A total of 631 bacterial isolates, clustered into seven operational taxonomic units, namely Acinetobacter, Bacillus, Klebsiella, Proteus and Kosakonia, Kurthia, and Yokenella, that are reported for the first time were recovered from the foods. One hundred and eleven metabolites comprising mycotoxins and other fungal metabolites, phytoestrogenic phenols, phytotoxins, and bacterial metabolites were detected in the foods. Aflatoxins, fumonisins, and ochratoxins contaminated only the artisanal foods (aadun, eko, and kokoro), while deoxynivalenol and zearalenone were found in industrially-processed foods (biscuit, bread, and shawarma), and citrinin was present in all foods except eko. Mean aflatoxin (39.0 µg/kg) in artisanal foods exceeded the 10 µg/kg regulatory limit adopted in Nigeria by threefold. Routine surveillance, especially at the informal markets; food hygiene and safety education to food processors and handlers; and sourcing of high-quality raw materials are proposed to enhance RTE food quality and safeguard consumer health.