Agents Of Foodborne Diseases Research Articles

Into the Jungle of Biological Agents of Foodborne Diseases: Time to Put Some Order for the French Risk Manager.

Consumers can be exposed to many foodborne biological hazards that cause diseases with varying outcomes and incidence and, therefore, represent different levels of public health burden. To help the French risk managers to rank these hazards and to prioritize food safety actions, we have developed a three-step approach. The first step was to develop a list of foodborne hazards of health concern in mainland France. From an initial list of 335 human pathogenic biological agents, the final list of "retained hazards" consists of 24 hazards, including 12 bacteria (including bacterial toxins and metabolites), 3 viruses and 9 parasites. The second step was to collect data to estimate the disease burden (incidence, Disability Adjusted Life Years) associated with these hazards through food during two time periods: 2008-2013 and 2014-2019. The ranks of the different hazards changed slightly according to the considered period. The third step was the ranking of hazards according to a multicriteria decision support model using the ELECTRE III method. Three ranking criteria were used, where two reflect the severity of the effects (Years of life lost and Years lost due to disability) and one reflects the likelihood (incidence) of the disease. The multicriteria decision analysis approach takes into account the preferences of the risk managers through different sets of weights and the uncertainties associated with the data. The method and the data collected allowed to estimate the health burden of foodborne biological hazards in mainland France and to define a prioritization list for the health authorities.

Distribution ofListeria spp., andListeria monocytogenesin micro- and small-scale meat product processing plants

Listeriosis is a disease caused by L. monocytogenes, a relevant microorganism as a causative agent of foodborne diseases - FBD. This study aimed to evaluate the distribution of Listeria spp., and L. monocytogenes in different production areas in two small plants (A and B) and two micro-food processing plants (C and D) producing meat derivatives, located in different cities of Colombia. The methodology implemented was i. The analysis of sampling points is based on a harmonised tool. ii. Four samplings in each production plant between 2019 and 2020. iii. Isolation and identification of microorganisms through conventional microbiology, a semi-automated system, molecular serotyping and clonal characterisation by ERIC-PCR. L. monocytogenes frequency in the production plants belonging to the study ranged between 5.9 and 28.6 %; for Listeria spp., plants A and D had isolated, plant A had the highest proportion, while for L. monocytogenes geno-serotypes found were: 1/2a, 1/2c, 4a-4c, 4b, 4d - 4e, with geno-serotype 4b as the most frequent. Furthermore, possible persistent isolates were detected in plant C as the feasible sources of contamination, based on failures in flow management, raw material contaminated with L. monocytogenes, lack of standardised cooking processes and transfer of the microorganism through equipment and surfaces. Finally, in three of the four production plants assayed, L. monocytogenes or Listeria spp. were present in the packaging area in some of the samples taken during the study, which calls for increased and frequent monitoring, as well as constant technical support for the control of L. monocytogenes in micro and small-scale production plants.

Prevalence and colonization of fungi in dried food (garri) obtained from Ikere-Ekiti

Garri is consumed by several millions of people in the West African sub-region and in Nigeria in particular, regardless of ethnicity and socio-economic class. However, production and handling methods have not been standardized resulting in garri product with varying mycological contamination. The objective of this study was to assess the mycological safety and mycological contamination of garri marketed in Ikere-Ekiti, Ekiti State. A total of eight (8) samples of garri displayed in the open at Ikere-Ekiti markets were used for this study. The samples were collected with sterile polythene bags adopting standard procedures and transported to the laboratory for analysis. The result of this study clearly showed fungal contamination resulting from its display in the open market, Aspergillus spp. and Mucor sp. had the highest frequency of occurrence and Aspergillus spp. was the fungi most frequently isolated. Other fungi species isolated in the garri samples were Absidia spp., Botrytis spp., Penicillium spp. and Rhizopus spp. Since this product harbor arrays of fungi, strategy to antagonize their growth and survival in this commodity in order to neutralize the potential of these organisms serving as agents of food borne diseases should be adopted.

Serotypes, Pathotypes, Shiga Toxin Variants and Antimicrobial Resistance in Diarrheagenic Escherichia coli Isolated from Rectal Swabs and Sheep Carcasses in an Abattoir in Mexico

Sheep represent one of the main reservoirs of diarrheagenic Escherichia coli; this microorganism is an etiological agent of food-borne diseases; therefore, this work aimed to identify and characterize the principal pathotypes of diarrheagenic E. coli (DEC) obtained through rectal swabs and carcasses samples from sheep slaughtered in an abattoir at the central region of Mexico. The isolates were subjected to bacteriological identification, serotyping; phylogenetic classification; detection for virulence factors, and antimicrobial sensibility. A total of 90 E. coli isolates were obtained. It was observed through 49 E. coli isolates (54%), 8 of them from carcasses, and 43 from feces was DEC. DEC serotypes with health public relevance were found: O76:H19 (n = 5), O146:H21 (n = 3), O91:H10 (n = 1), O6:NM (n = 1), and O8:NM (n = 1). Regarding the presence of Shiga toxin-producing E.coli (STEC), 43/90 (47.7%) isolates have the stx1 w/o stx2 genes, and therefore were assigned as STEC non-O157; only one isolate expressed stx1 and eae genes and was classified as t-STEC (typical STEC). Additionally, 3/90 (3.3%) harbored only the eae gene and were classified as enteropathogenic E. coli (EPEC), the stp gene was found in 2/90 isolates (2.2%) and were classified as enterotoxigenic E. coli (ETEC); 1/90 (1.1%) isolates harboring the ipaH were classified as enteroinvasive E. coli EIEC. Regarding stx1 genes subtypes, stx1c only was found in 60.5% (26/43), followed by stx1a-stx1c 20.9% (9/43) and stx1a-stx1d 2.3% (1/43). The presence of both, stx1 and stx2 genes was found in 7/43 isolates (16.3%) from rectal swabs; the combination stx1c-stx2g was detected in 3/43 isolates (6.9%), while 4 (9.4%) isolates showed different patterns (stx1a-stx1c-stx2g; stx1c-stx2b-stx2g; stx1c-stx2b and stx1a-stx1c-stx2b-stx2g). STEC isolates showed the major diversity of phylogenetic groups, although phylogroup B1 was predominant in 90.6% (39/43) while there was only one isolate (2.3%) in each remaining phylogroup (A, B2, C, and F). All EPEC, ETEC, and EIEC isolates were clustered in phylogroup B1. We observed that 27.9% (12/43) of STEC isolates carried at least one antibiotic resistance: nine isolates expressed the tetB gene, one isolate the tetA gene, two isolates the sul2 gene, one isolate the sul1 and one isolate the sul1-tetB genes. These results highlight the importance of diarrheagenic E. coli as a potential risk for public health during the slaughtering process.

Predictive Population Dynamics of Escherichia coli O157:H7 and Salmonella enterica on Plants: a Mechanistic Mathematical Model Based on Weather Parameters and Bacterial State.

Weather affects key aspects of bacterial behavior on plants but has not been extensively investigated as a tool to assess risk of crop contamination with human foodborne pathogens. A novel mechanistic model informed by weather factors and bacterial state was developed to predict population dynamics on leafy vegetables and tested against published data tracking Escherichia coli O157:H7 (EcO157) and Salmonella enterica populations on lettuce and cilantro plants. The model utilizes temperature, radiation, and dew point depression to characterize pathogen growth and decay rates. Additionally, the model incorporates the population level effect of bacterial physiological state dynamics in the phyllosphere in terms of the duration and frequency of specific weather parameters. The model accurately predicted EcO157 and S. enterica population sizes on lettuce and cilantro leaves in the laboratory under various conditions of temperature, relative humidity, light intensity, and cycles of leaf wetness and dryness. Importantly, the model successfully predicted EcO157 population dynamics on 4-week-old romaine lettuce plants under variable weather conditions in nearly all field trials. Prediction of initial EcO157 population decay rates after inoculation of 6-week-old romaine plants in the same field study was better than that of long-term survival. This suggests that future augmentation of the model should consider plant age and species morphology by including additional physical parameters. Our results highlight the potential of a comprehensive weather-based model in predicting contamination risk in the field. Such a modeling approach would additionally be valuable for timing field sampling in quality control to ensure the microbial safety of produce. IMPORTANCE Fruits and vegetables are important sources of foodborne disease. Novel approaches to improve the microbial safety of produce are greatly lacking. Given that bacterial behavior on plant surfaces is highly dependent on weather factors, risk assessment informed by meteorological data may be an effective tool to integrate into strategies to prevent crop contamination. A mathematical model was developed to predict the population trends of pathogenic E. coli and S. enterica, two major causal agents of foodborne disease associated with produce, on leaves. Our model is based on weather parameters and rates of switching between the active (growing) and inactive (nongrowing) bacterial state resulting from prevailing environmental conditions on leaf surfaces. We demonstrate that the model has the ability to accurately predict dynamics of enteric pathogens on leaves and, notably, sizes of populations of pathogenic E. coli over time after inoculation onto the leaves of young lettuce plants in the field.

The genomic approach of antimicrobial resistance of Salmonella Typhimurium isolates from guinea pigs in Lima, Peru

Salmonella Typhimurium is an important agent of foodborne diseases. In Peru, the emergence of multidrug-resistant isolates of S. Typhimurium from the food chain could be linked to guinea pig farming as a potential reservoir and their uncontrolled antibiotic treatment against salmonellosis. In this study, we performed the sequencing, genomic diversity, and characterization of resistance elements transmitted by isolates from farm and meat guinea pigs. The genomic diversity and antimicrobial resistance of S. Typhimurium isolates were performed using nucleotide similarity, cgMLST, serotyping, phylogenomic analyses, and characterization of resistance plasmids. We found at least four populations of isolates from farm guinea pigs and four populations from meat guinea pigs without finding isolated transmission between both resources. Genotypic resistance to antibiotics was observed in at least 50% of the isolates. Among the farm guinea pig isolates, ten were found to be resistant to nalidixic acid, and two isolates exhibited multidrug resistance to aminoglycosides, tetracycline-fluoroquinolone (carrying strA-strB-tetA-tetB genes and gyrA S83F mutation), or trimethoprim-sulfonamide (carrying AaadA1-drfA15-sul1 genes). Additionally, two isolates from the meat source were resistant to fluoroquinolones (one of which had enrofloxacin resistance). The transmissible resistance plasmids with insertion sequences (IS) such as IncI-gamma-K1-ISE3-IS6, IncI1-I (alpha)-IS21-Tn10, and Col (pHAD28) were commonly found in isolates belonging to the HC100-9757 cluster from both guinea pigs and human hosts. Altogether, our work provides resistance determinants profiles and Salmonella sp. circulating lineages using WGS data that can promote better sanitary control and adequate antimicrobial prescription.

Retrospective Screening of Anthrax-like Disease Induced by Bacillus tropicus str. JMT from Chinese Soft-Shell Turtles in Taiwan.

Bacillus cereus is ubiquitous in the environment and a well-known causative agent of foodborne disease. Surprisingly, more and more emerging strains of atypical B. cereus have been identified and related to severe disease in humans and mammals such as chimpanzees, apes, and bovine. Recently, the atypical B. cereus isolates, which mainly derive from North America and Africa, have drawn great attention due to the potential risk of zoonosis. The cluster of B. cereus carries several anthrax-like virulent genes that are implicated in lethal disease. However, in non-mammals, the distribution of atypical B. cereus is still unknown. In this study, we conducted a retrospective screening of the 32 isolates of Bacillus spp. from diseased Chinese soft-shelled turtles from 2016 to 2020. To recognize the causative agent, we used various methods, such as sequencing analysis using PCR-amplification of the 16S rRNA gene, multiplex PCR for discriminating, and colony morphology by following previous studies. Furthermore, the digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were calculated, respectively, below the 70 and 96% cutoff to define species boundaries. According to the summarized results, the pathogen is taxonomically classified as Bacillus tropicus str. JMT (previous atypical Bacillus cereus). Subsequently, analyses such as targeting the unique genes using PCR and visual observation of the bacteria under various staining techniques were implemented in our study. Our findings show that all (32/32, 100%) isolates in this retrospective screening share similar phenotypical properties and carry the protective antigen (PA), edema factor (EF), hyaluronic acid (HA), and exopolysaccharide (Bps) genes on their plasmids. In this study, the results indicate that the geographic distribution and host range of B. tropicus were previously underestimated.

Quantificação deAeromonassp. em peixes de água doce e resistência a antimicrobianos: patógeno emergente

ABSTRACT: The bacteria Aeromonassp. are naturally reported in aquatic ecosystems and possess pathogenic potential, being considered as emerging pathogens in humans and animals. They also cause considerable losses in fish farming and, through water, can contaminate numerous foods. This study quantified and analyzed the antimicrobial resistance profile of Aeromonassp. in fish. A total of 72 samples of two fish varieties (leather fish, Pseudoplatystomafasciatumx Leiariusmarmoratusand round fish, Colossomamacropomumx Piaractusmesopotamicusand Colossomamacropomumx Piaractusbrachypomus) were purchased from two types of sources (fresh and frozen) and three commercial establishments (supermarket, market, and fishmonger). The 55 isolated Aeromonascultures were evaluated for their antimicrobial resistance profile by the disc diffusion method. Upon quantification, the count of Aeromonassp. ranged from 4.22 to 6.00 Log CFU/g; ten different species, including A. eucrenophila, A. hydrophila, A. caviae, A. media, A. jandaei, A. veroniibv. sobria, A. trota, A. schubertii, A. veroniibv. veronii, and A. shigelloides, were identified. Among the 55 isolates, 64.45% showed resistance to Ampicillin-sulbactam, and 75% were sensitive to gentamicin and ciprofloxacin. It was concluded that 100% of the evaluated samples were contaminated by Aeromonassp., which may present a risk to consumer health since bacteria can be etiological agents of Foodborne Diseases. The antimicrobial resistance profile showed resistance to ampicillin and multi-resistance to different classes of antimicrobials, demonstrating problems with choosing an antimicrobial for treatment of any disease.

Detection of Contamination Salmonella sp. of Beef in Banyuwangi Traditional Market

Salmonella sp. is one of the bacteria from Food-Borne Disease agents, can contaminate meat and cause salmonellosis. According to National Indonesian Standard 2009, meat is safe for consumption if it has a negative result of salmonella in 25 grams of meat. The purpose of this study was to determine whether there was contamination of Salmonella sp. on beef sold in the traditional market of Banyuwangi District. A total of 18 samples used in this study were taken according to the criteria for isolation and identification. All samples were enriched with the pre-enrichment stage using Lactose Broth media, and the enrichment medium using Tetrathionate Broth. Furthermore, in the isolation stage using Salmonella Shigella Agar (SSA) media. Then proceed with the identification stage using the Triple Sugar Iron Agar (TSIA) test, the Sulfide Indole Motility (SIM) test, and the Urease test. The results showed that 5 out of 18 samples tested positive for Salmonella.

A quantitative prevalence of Escherichia coliO157 in different food samples using real-time qPCR method.

Escherichia coli serogroup O157 is the main causative agent of several intestinal and extra-intestinal foodborne diseases in humans through consumption of low-dose contaminated foods such as milk, beef, and vegetables. To date, studies regarding the quantitative prevalence of E.coli O157 in foods are so limited. Therefore, this study aimed to evaluate the quantitative prevalence rate of E.coli serogroup O157 in raw milk (n= 144), vegetable salad (n= 174), and minced beef samples (n= 108) using the real-time qPCR SYBR green melting curve method targeting the rfbA gene. First, we evaluated the method and found a sensitive and specific qPCR assay with 1 log of CFU/ml detection limit to detect E.coli O157 (Tm=80.3± 0.1°C). About 2.77%, 10.18%, and 9.19% of raw milk, minced beef, and vegetable salad samples, respectively, were contaminated with E.coli O157. Minced beef and vegetable salad samples were significantly more contaminated than raw milk samples. Population average of E.coli O157 in raw milk, minced beef, and vegetable salad samples were 2.22 ± 0.57, 3.30 ± 0.40, and 1.65 ± 0.44 log CFU/ml or gr, respectively. Significantly higher levels of population of E.coli O157 were observed in minced beef samples. Minced beef can be regarded as the main food in the transmission of this foodborne pathogen. Routine quantitative rapid monitoring is strongly suggested to be carried out to prevent foodborne diseases caused by E.coli O157.

Occurrence of Cryptosporidium spp. in Traditional Milk and Dairy Products Supplied in Yazd City, Central Iran

Background: Cryptosporidium is one of the most important agents of food-borne diseases with gastrointestinal symptoms such as diarrhea in either livestock or humans. This protozoon can be transmitted to human through consuming contaminated raw milk and dairy products. The present study aimed to detect Cryptosporidium spp. in traditional raw cow milk, cream, and cheese consumed in Yazd city, Central Iran.
 Methods: Two hundred traditional (unpasteurized) milk and dairy samples were collected from five different regions of the studied area, including 100 traditional cow milk, 50 cow cheese, and 50 cow cream. DNA extraction was performed. Then, molecular detection was performed using the nested Polymerase Chain Reaction technique. Statistical analysis was performed using SPSS version 23.0.
 Results: The findings of this study showed that 11% samples were contaminated with Cryptosporidium spp., including 4.0% (4/100) milk, 18.0% (9/50) cream, and 18.0% (9/50) cheese (p<0.05). Besides, parasite contamination was 8.8, 12.5, 12.8, 8.3, and 12.8% in the Center, North, East, South, and West of the studied region, respectively (p>0.05).
 Conclusion: Due to the occurrence of Cryptosporidium spp. in unpasteurized dairy samples in Central Iran, developing and designing control and prevention programs is necessary against this parasite.

A Small‐molecule Inhibitor VM17 Targeting a Transcriptional Regulator HlyU Attenuates the Virulence of Vibrio vulnificus

Vibrio vulnificusis a causative agent of food‐borne diseases including gastroenteritis and life‐threatening septicemia. Exotoxins such as a multifunctional‐autoprocessing repeats‐in‐toxin (MARTX) toxin, a hemolysin, and a phospholipase A2 encoded by rtxA, vvhA, and plpAgenes, respectively, are essential virulence factors. Interestingly, the expression of rtxA, vvhA, and plpA is activated by a transcriptional regulator HlyU. Therefore, HlyU can be an attractive target to control the virulence of V. vulnificus. We performed a high‐throughput screening of 8,364 molecules at 20 µM using Escherichia coli containing HlyU‐expressing and HlyU‐dependent reporter plasmids. A small molecule VM17 exhibiting the most effective HlyU‐inhibiting activity was selected and verified. VM17 did not affect the cellular HlyU levels, indicating that VM17 could inhibit the HlyU activity. The expression of rtxA, vvhA, and plpAin the wild type was significantly reduced in the presence of 20 µM of VM17. Consistent with this, VM17 enhanced the survival rate of the mice infected with V. vulnificus, indicating that the small molecule inhibits the virulence of V. vulnificus in vitroand in vivo. In conclusion, the combined results suggested that VM17 could be a novel lead compound to attenuate the virulence of V. vulnificuswith a low probability of developing resistance.

Antimicrobial Resistance and Molecular Detection of Extended

Escherichia coli (E. coli) are common etiological agents of food borne diseases. A study on antimicrobial resistance and molecular detection of Extended-Spectrum β-lactamase resistance (ESBL) in E. coli from road-side suya meat was carried out. Suya meat (50 each from Akwanga, Nasarawa Eggon and Wamba) were collected; and E. coli was isolated and identified using cultural, morphological and biochemical characteristics. Antimicrobial susceptibility testing was carried out using disc diffusion method and interpreted as described by the Clinical and Laboratory Standards Institute. The phenotypic detection of ESBL production in multi-drug resistant isolates was carried using double disc synergy test. Screening for ESBL genes namely blaTEM, blaSHV and blaCTX-M was carried out using polymerase chain reaction (PCR) method. The overall percentage occurrence of the isolates was 11(7.3%), being highest in wamba (10.0%), and lowest in Nasarawa Eggon (4.0%). The isolates were more resistant to amoxicillin/clavulanic acid, cefotaxime, and ceftazidine (54.5%). Percentage occurrence of ESBL producing isolates was 4(36.4%). Multidrug resistance (MDR) isolates (63.6%) occurred more than extensive drug resistance (XDR) (36.4%). The percentage occurrence of ESBL genes namely: blaSHV and blaTEM were 3 (75.0%). The Beta-lactam antibiotics such as amoxicillin/clavulanic acid, ceftazidime and cefotaxime were effective against the isolates and most of the isolates were ESBL resistant.

Molecular analysis of pathogenic Escherichia coli isolated from cow meat in Yogyakarta, Indonesia using 16S rRNA gene

Abstract. Indraswari A, Suardana IW, Haryanto A, Widiasih DA. 2021. Molecular analysis of pathogenic Escherichia coli isolated from cow meat in Yogyakarta, Indonesia using 16S rRNA gene. Biodiversitas 22: 4566-4573. Meat has been recognized as a major source of foodborne disease and a public health problem. The characteristics of meat become an ideal growth medium for various microorganisms if not handled properly. Pathogenic Escherichia coli is one of the foodborne disease agents that causes diarrhea. Identification of pathogenic E. coli isolated from cow meat needs to be done. This research aims to study nucleotide sequence of 16S rRNA gene of pathogenic E. coli isolated from cow meat in Yogyakarta, Indonesia using Polymerase Chain Reaction (PCR). These fifteen isolates have been detected for eae target gene, then amplification of the 16S rRNA gene was carried out using primers 27F and 1492R. Phylogenetic tree reconstruction was performed on the fifteen isolates of pathogenic E. coli to figure out the relationship to reference strains available at the GenBank. Results show that nucleotide sequence among the fifteen isolates from different traditional markets in Yogyakarta, Indonesia and reference strains are very similar. The fifteen isolates have small genetic distance to the reference strains, and these fifteen isolates are also in the same clade with reference strains. This research shows that the fifteen isolates under investigation are closely related to the reference strains, which is Shiga-toxin producing E. coli (STEC). People should pay more attention in processing food stock, especially cow meat. Further research may focus on determining the strain of those fifteen isolates.

Genomic and Phenotypic Characteristics for Vibrio vulnificus Infections.

BackgroundVibrio vulnificus (VV) is a causative agent of foodborne diseases with high mortality. The aim of this study was to investigate the genomic and phenotypic profiles of VV.MethodsSix VV isolates were collected and conducted whole-genome sequencing. Biofilm formation and anti-complement killing test were performed to evaluate the pathogenicity. Subsequently, 157 publicly available genomes of VV isolates were selected to determine the evolutionary relationship.ResultsThe resistant genes norM and tet34 were identified in six isolates. A total of 156 virulence genes were identified. However, there is no obvious difference between strains isolated from blood and puncture fluid. The tendency of growth for six isolates decreased with the lapse of time, while the biofilm formation increased. The genes tadC and flp related to Flp pili were found in isolate 25506 and 30896, resulting in more obvious biofilm formation. In addition, the survival rate of 19656 was less than 20% due to lack of one genomic island including virulence genes (impD-H, clpV-1) relevant to type VI secretion system (T6SS). Multi-locus sequence typing (MLST) revealed 95 different STs and 19 novel STs, indicating that the tendency of 163 isolates was sporadic. Further comparative genomics analysis clearly classified 163 isolates into three distinct evolutionary lineages.ConclusionVV infections were sporadic in humans and the environment. Virulence genes impD-H and clpV-1 related to T6SS were associated with pathogenicity phenotype of VV.

Evaluation of PhageDX Salmonella Assay for Salmonella Detection in Hydroponic Curly Lettuce.

Lettuce is one of the most consumed leafy vegetables worldwide and has been involved in multiple foodborne outbreaks. Salmonella is one of the most prevalent etiological agents of foodborne disease (FBD) in lettuces, and its detection may take several days depending on the chosen method. This study evaluates a new rapid method that uses recombinant bacteriophages to detect Salmonella in hydroponic curly lettuce. First, the ability of the assay to detect six Salmonella serovars at three different concentrations (1, 10, and 100 CFU/well) was tested. Second, the detection of Salmonella was tested in lettuces using a cocktail of the same Salmonella serovars and concentrations after a 7 h enrichment. The results of these experiments showed that the detection limit was dependent on the serovar tested. Most serovars were detected in only 2 h when the concentration was 100 CFU/well. Salmonella was detected in 9 h (7 h enrichment + 2 h bioluminescence assay) in all lettuce samples with 10 CFU/25 g or more. Salmonella detection was not influenced by natural microbiota of lettuces. This study demonstrated that the phage assay was sensitive and faster than other detection methods, indicating that it is a better alternative for Salmonella detection on lettuces.

Antiviral Potential of Plants against Noroviruses.

Human noroviruses, which belong to the enterovirus family, are one of the most common etiological agents of food-borne diseases. In recent years, intensive research has been carried out regarding the antiviral activity of plant metabolites that could be used for the preservation of fresh food, because they are safer for consumption when compared to synthetic chemicals. Plant preparations with proven antimicrobial activity differ in their chemical compositions, which significantly affects their biological activity. Our review aimed to present the results of research related to the characteristics, applicability, and mechanisms of the action of various plant-based preparations and metabolites against norovirus. New strategies to combat intestinal viruses are necessary, not only to ensure food safety and reduce infections in humans but also to lower the direct health costs associated with them.

Bacillus cereus food intoxication and toxicoinfection.

Bacillus cereus is one of the leading etiological agents of toxin-induced foodborne diseases. Its omnipresence in different environments, spore formation, and its ability to adapt to varying conditions and produce harmful toxins make this pathogen a health hazard that should not be underestimated. Food poisoning by B. cereus can manifest itself as an emetic or diarrheal syndrome. The former is caused by the release of the potent peptide toxin cereulide, whereas the latter is the result of proteinaceous enterotoxins (e.g., hemolysin BL, nonhemolytic enterotoxin, and cytotoxin K). The final harmful effect is not only toxin and strain dependent, but is also affected by the stress responses, accessory virulence factors, and phenotypic properties under extrinsic, intrinsic, and explicit food conditions and host-related environment. Infamous portrait of B. cereus as a foodborne pathogen, as well as a causative agent of nongastrointestinal infections and even nosocomial complications, has inspired vast volumes of multidisciplinary research in food and clinical domains. As a result, extensive original data became available asking for a new, both broad and deep, multifaceted look into the current state-of-the art regarding the role of B. cereus in food safety. In this review, we first provide an overview of the latest knowledge on B. cereus toxins and accessory virulence factors. Second, we describe the novel taxonomy and some of the most pertinent phenotypic characteristics of B. cereus related to food safety. We link these aspects to toxin production, overall pathogenesis, and interactions with its human host. Then we reflect on the prevalence of different toxinotypes in foods opening the scene for epidemiological aspects of B. cereus foodborne diseases and methods available to prevent food poisoning including overview of the different available methods to detect B. cereus and its toxins.

Culture-Dependent Evaluation of Microbial and Proximate Composition of Ready-to-Eat (RTE) African Salad Sold at Nkpolu-Oroworukwo Ultra-Modern Market (Mile 3, Diobu), Port Harcourt, Rivers State, Nigeria

This study attempts to evaluate culture-dependent microbial and proximate composition of African salad (Abacha) sold at Nkpolu Oroworukwo (mile 3) market, Port Harcourt, Rivers State, Nigeria. Samples were bought from stationary vendors at market within the months of March, 2019 to March, 2021. Garnished African salad (GAS) and ungarnished African salad (UAS) samples were determined by standard microbiological techniques whereas proximate composition (PC) was analysed by the methods of Association of Official of Analytical Chemists (AOAC) Total aerobic plate counts (TAPCs), total coliform counts (TCCs) and fungal counts (FCs) of GAS were higher 4.5x104CFU/g, 5.3x104CFU/g and 1.1x104CFU/g respectively as against 3.4x104CFU/g, 3.8x104 CFU/g and 0.8x104CFU/g for UAG. Microfloral diversity were more in GAS with species such as Escherichia coli, Bacillus subtilis, Klebsiella sp., Micrococcus sp.. Bacillus sp., Enterobacter sp., and Aspergillus sp., Penicillium sp., Rhizopus sp., Fusarium sp., Mucor sp., Saccharomyces and Candida species than in UAS. Nutrient composition, energy (116.00Kcal/100g) and pH (6.4) values were higher in GAS. In contrast, only the moisture (62.52±0.53%) and carbohydrate (23.21±0.21%) contents were slightly higher in UAS than those in GAS. The study revealed that African salad’ bioburden was slightly above the microbiological standard limits of International Commission on Microbiological Specification for Foods (ICMSF) and (Public Health Laboratory Service (PHLS) for RTE foods for mesophilic aerobic bacteria (MAB)/TAPC but exceeded that for total coliforms. However, the microbes detected are likely aetiologic agents of several food borne diseases (FBDs) in human and animal pathologies. Therefore, adequate surveillance, monitoring and compliance with hygienic practices and environmental sanitary measures during processing, fortification and distribution should be enforced by regulatory agencies and stakeholders for wholesome and palatable RTE foods.

Antimicrobial resistance genes and class 1 integrons in MDR Salmonella strains isolated from swine lymph nodes

Food safety is essential to the development of a society, and foodborne diseases affect thousands of people worldwide every year. Among the main foodborne disease agents, Salmonella stands out as the most often associated with hospitalizations and deaths. Pork products are an important source of nutrients for the population, considered the most consumed meat in the world. Several reports revealed the presence of Multidrug-Resistant (MDR) Salmonella strains along the pork production chain, and the occurrence of elements that allow for the transference of resistance genes between bacterial populations is a public health concern. The present work aimed to evaluate the resistance genes and integrons in MDR Salmonella strains isolated from swine mesenteric lymph nodes. Nine strains had the genome sequenced with the Illumina NextSeq system. The results were submitted to the Resfinder server for evaluation of acquired genes and point mutations related to AMR and the presence and sequences of integrons were determined with a BLAST search. Different resistance genes for the same antimicrobial class were present in each strain. In two samples, resistance genes for olaquindox, a growth promoter outlawed in Brazil since 2004, were found. All observed phenotypic resistance had a genetic basis. Five isolates harbored class 1 integrons, which were classified in three distinct Integron Profiles (IPs). The IPs were also reported in animal source food and human clinical isolates. The diversity of resistance genes for the same antimicrobial class in each strain and the presence of Class 1 Integrons, reflect the high selection pressure that these bacterial lineages face along the pork production chain, and reinforces the role of animal production as a reservoir and disseminator of AMR genes.