Dangerous Foodborne Pathogens Research Articles

Occurrence, Molecular Serogroups, Antimicrobial Susceptibility and Identification by MALDI-TOF MS of Listeria monocytogenes Isolated from RTE Meat Products in Southern Poland.

L. monocytogenes is considered one of the most dangerous foodborne pathogens. This study aimed to determine the occurrence of L. monocytogenes in RTE meat products from southern Poland, including serogroups and antimicrobial susceptibility, and to assess the usefulness of MALDI-TOF MS as a tool for identifying L. monocytogenes. A total of 848 production batches of RTE meat products were analyzed for L. monocytogenes. All L. monocytogenes isolates were serotyped using the multiplex PCR method, tested for antimicrobial susceptibility using the disk diffusion method and identified using the MALDI-TOF MS method. L. monocytogenes was detected in 52/848 batches of RTE meat products (6.13%). The isolates belonged to four serogroups: 17/52 (33%) isolates to IVb; 15/52 (29%) isolates to IIa; 10/52 (19%) isolates to IIc and 10/52 (19%) isolates to IIb. All isolates (52/52) showed susceptibility to the tested antimicrobials. Using MALDI-TOF MS, 10/52 isolates (19.2%) were identified at the level of secure genus identification, probable species identification; 37/52 isolates (71.2%) were identified at the level of probable genus identification; 3/52 isolates (5.8%) were incorrectly identified as L. innocua; and 2/52 isolates (3.8%) were not identified. The occurrence of L. monocytogenes in RTE meat products was low. Almost half of the analyzed isolates were L. monocytogenes of serogroups, which are most often associated with listeriosis in humans in Poland. All isolates showed susceptibility to five commonly used antimicrobials for treating listeriosis. The use of MALDI-TOF MS as a tool for the identification of L. monocytogenes indicated its limitations related to the insufficient representation of the pathogen in the reference database.

Aptamer-carbon quantum dots and silver nanoparticles construct a FRET sensor for sensitive detection of E. coli

E. coli is considered to be one of the most dangerous foodborne pathogens and precise detection of E. coli in food is required to ensure the quality and safety of food. In this work, carbon quantum dots (CQDs) were prepared from grapefruit peel as a carbon source by microwave heating method. A fluorescent resonance energy transfer (FRET)-based fluorescent biosensor was constructed by combining CQDs with silver nanoparticles (Ag NPs) for rapid detection of E. coli (BL21). The prepared CQDs showed good dispersion under transmission electron microscopy (TEM), with a spherical shape and an average particle size of 7.4 nm. The CQDs showed bright green fluorescence under UV light irradiation, which was strongly fluorescent (> 1.0 × 103 a.u.) and there was no change in fluorescence intensity over 150 days. Its fluorescence transduction is based on the spectral overlap between the donor (CQDs) emission and the acceptor (nanoparticles) absorbance. The fluorescence of CQDs attached to the aptamer is burst in the presence of Ag NPs. Upon addition of a specific E. coli (BL21) solution, an aptamer-target complex is formed and the preferential interaction of the aptamer with the specific bacteria leads to the release of CQDs and Ag NPs. After a period of incubation, the bacteria are centrifuged, resulting in the precipitation of E. coli aptamer couples and Ag NPs, and therefore the recovery of CQDs fluorescence. This method allows specific detection of E. coli (BL21) in a wide range of pathogenic bacteria. The final results show that the sensor has a linear range of 2×103 ∼ 2×108 CFU·mL−1 and a low detection limit of 77 CFU·mL−1 for E. coli.

Drain biofilm microbiota inside a cheese processing facility: Comparison of Listeria positive and Listeria negative drains

Listeria monocytogenes was identified as one of the most dangerous food-borne pathogens of the 21st century, not only due to its high mortality rate but also because of its ability to establish itself as a part of drain biofilms and persist there over long periods of time. The insides of twelve drains in a cheese processing facility were swabbed over a period of five months. Bacterial DNA was isolated and quantified to ascertain the presence and abundance of the biofilm. Presence of Listeria spp. prs gene was found in four of the twelve drains, with one drain testing positive for the prs gene presence on three different occasions. 16S rRNA amplicon sequencing was conducted on the isolated DNA from two Listeria positive and two Listeria negative drains. The microbial community composition was evaluated. Most notably genera Streptococci and unclassified Lactobacillales were significantly different in abundance in the Listeria negative drains. Genera Flavobacterium and unclassified Xanthomonadaceae were found to be significantly more different in abundance in the LisTeria positive drains. The latter two genera were not previously associated with Listeria spp. or reported to be widespread in food processing environments (FPE), however, they help to illustrate the higher diversity that was seen in Listeria positive drains. This study suggests that even though the alpha diversity is not sigN ificantly different, there are differences between the drain biofilm composition between Listeria positive and Listeria negative drains, which can be further researched to ascertain how these organisms affect the presence of Listeria spp. inside drain biofilms.

Why does Listeria monocytogenes survive in food and food-production environments?

Listeria monocytogenes is one of the most dangerous food-borne pathogens and is responsible for human listeriosis, a severe disease with a high mortality rate, especially among the elderly, pregnant women and newborns. Therefore, this bacterium has an important impact on food safety and public health. It is able to survive and even grow in a temperature range from -0.4°C to 45°C, a broad pH range from 4.6 to 9.5 and at a relatively low water activity (aW < 0.90), and tolerates salt content up to 20%. It is also resistant to ultraviolet light, biocides and heavy metals and forms biofilm structures on a variety of surfaces in food-production environments. These features make it difficult to remove and allow it to persist for a long time, increasing the risk of contamination of food-production facilities and ultimately of food. In the present review, the key mechanisms of the pathogen's survival and stress adaptation have been presented. This information may grant better understanding of bacterial adaptation to food environmental conditions.

Whole-Genome Analysis of Antimicrobial-Resistant Salmonella enterica Isolated from Duck Carcasses in Hanoi, Vietnam.

Salmonella enterica is one of the most dangerous foodborne pathogens listed by the World Health Organization. In this study, whole-duck samples were collected at wet markets in five districts in Hanoi, Vietnam, in October 2019 to assess their Salmonella infection rates and evaluate the susceptibility of the isolated strains to antibiotics currently used in the prophylaxis and treatment of Salmonella infection. Based on the antibiotic resistance profiles, eight multidrug resistance strains were whole-genome-sequenced, and their antibiotic resistance genes, genotypes, multi-locus sequence-based typing (MLST), virulence factors, and plasmids were analyzed. The results of the antibiotic susceptibility test indicate that phenotypic resistance to tetracycline and cefazolin was the most common (82.4%, 28/34 samples). However, all isolates were susceptible to cefoxitin and meropenem. Among the eight sequenced strains, we identified 43 genes associated with resistance to multiple classes of antibiotics such as aminoglycoside, beta-lactam, chloramphenicol, lincosamide, quinolone, and tetracycline. Notably, all strains carried the blaCTX-M-55 gene, which confers resistance to third-generation antibiotics including cefotaxime, cefoperazone, ceftizoxime, and ceftazidime, as well as resistance genes of other broad-spectrum antibiotics used in clinical treatment such as gentamicin, tetracycline, chloramphenicol, and ampicillin. Forty-three different antibiotic resistance genes were predicted to be present in the isolated Salmonella strains' genomes. In addition, three plasmids were predicted in two strains, 43_S11 and 60_S17. The sequenced genomes also indicated that all strains carried SPI-1, SPI-2, and SPI-3. These SPIs are composed of antimicrobial resistance gene clusters and thus represent a potential threat to public health management. Taken together, this study highlights the extent of multidrug-resistant Salmonella contamination in duck meat in Vietnam.

Мультирезистентные к антибиотикам штаммы и гены вирулентности salmonella strains, выделенной из мяса кур (Ханой, Вьетнам)

Salmonella enterica is one of dangerous food-borne pathogens listed by the World Health Organization (WHO). In Vietnam, poultry is one of the most widely eaten meats and is reported as a common source of S. enterica contamination. The aim of this study was to examine multi-resistant Salmonella strains, to identify susceptibility to antibiotics by using 15 different types of medications and to perform sequencing to analyze antibiotic resistance genes, genotypes, multi-locus sequence-based typing (MLST), and plasmids. The result of the antibiotic susceptibility test indicated that phenotypic resistance to 9–11 types of antimicrobials was confirmed in all strains. Among 06 sequenced strains, we identified 43 genes associated with antibiotic resistance: strains carrying a range of genes that are associated with aminoglycoside resistance (aac(3), aac(6), ant(3), aph(3), aph(6), aadA); all strains carried blaCTX-M-55 or blaCTX-M-65 gene, which were resistant to the 3rd generation antibiotics; there were also frequently observed sul1, sul2, sul3, tet (A), qnrS1, floR, dfrA14 or dfrA27 genes in sequenced isolates. Besides, the genome sequencing also indicated that all strains carried pathogenicity islands SPI 1, SPI 2, and SPI 3 thereby creating many potential triggers of the disease. Additionally, some carried C63PI, SPI 9, SPI 13, SPI 14, and plus some plasmids such as Col156, IncHI2, IncHI2A, IncFIB, Col (MGD2).

Strains and virulence genes of salmonella with multidrug resistance isolated from chicken carcasses (Hanoi, Vietnam)

Salmonella enterica is one of dangerous food-borne pathogens listed by the World Health Organization (WHO). In Vietnam, poultry is one of the most widely eaten meats and is reported as a common source of S. enterica contamination. The aim of this study was to examine multi-resistant Salmonella strains, to identify susceptibility to antibiotics by using 15 different types of medications and to perform sequencing to analyze antibiotic resistance genes, genotypes, multi-locus sequence-based typing (MLST), and plasmids. The result of the antibiotic susceptibility test indicated that phenotypic resistance to 9–11 types of antimicrobials was confirmed in all strains. Among 06 sequenced strains, we identified 43 genes associated with antibiotic resistance: strains carrying a range of genes that are associated with aminoglycoside resistance (aac(3), aac(6), ant(3), aph(3), aph(6), aadA); all strains carried blaCTX-M-55 or blaCTX-M-65 gene, which were resistant to the 3rd generation antibiotics; there were also frequently observed sul1, sul2, sul3, tet (A), qnrS1, floR, dfrA14 or dfrA27 genes in sequenced isolates. Besides, the genome sequencing also indicated that all strains carried pathogenicity islands SPI 1, SPI 2, and SPI 3 thereby creating many potential triggers of the disease. Additionally, some carried C63PI, SPI 9, SPI 13, SPI 14, and plus some plasmids such as Col156, IncHI2, IncHI2A, IncFIB, Col (MGD2).

Prevalence and whole-genome analysis of multidrug-resistant Salmonella isolated from chicken carcasses in Hanoi

Salmonella enterica is one of the most dangerous food-borne pathogens posing a significant global concern especially to travelers returning from developing countries. Given that chicken is the main reservoir for Salmonella, the emergence and spread of multi-drug resistant Salmonella from chicken have not been fully described in Vietnam. The present study aimed to evaluate the phenotypic and genotypic antimicrobial resistances of Salmonella from chicken carcasses. Among 104 raw chickens collected from 5 districts in Hanoi city, 65 samples were contaminated with Salmonella of which the highest contamination rate was found in Thanh Xuan. A total of 63/65 (96.9%) of Salmonella isolates were resistant to at least one antibiotic and 61/65 (93.9%) of the isolates were found to be multidrug resistant. Whole-genome sequencing was employed to analyze 4 strains with high (12_S2 and 61_S18) and low (19_S4 and 8_S1) antimicrobial resistance patterns. Genomic analysis indicated the presence of 27 genes conferring antibiotic resistance. Genotypes were highly correlated to observed phenotypes in 4 strains. Importantly, extended-spectrum β-lactamase blaCTX-M-55 and colistin resistance mcr-3 were reported in isolates of Salmonella enterica serovar Typhimurium. This is the first report showing the prevalence and genome sequences of Salmonella from chicken carcasses collected in Hanoi, Vietnam. The results represented herein provided the basis to understand the dynamics of antibiotic resistance of Salmonella in Vietnam and to spot antimicrobial resistance determinants for early diagnosis.

Ampicillin Treatment of Intracellular Listeria monocytogenes Triggers Formation of Persistent, Drug-Resistant L-Form Cells.

Listeria monocytogenes is an opportunistic intracellular pathogen causing an infection termed listeriosis. Despite the low incidence of listeriosis, the high mortality rate in individuals at risk makes this bacterium one of the most dangerous foodborne pathogens. Reports about a relapse of infection after antibiotic treatment suggest that the bacteria may be able to evade antibiotic treatment and persist as a dormant, antibiotic-tolerant subpopulation. In this study, we observed intracellular generation of antibiotic-resistant L-forms of Listeria monocytogenes following Ampicillin treatment of Listeria monocytogenes infected cells. Detection and identification of intracellular Listeria L-forms was performed by a combination of fluorescence in-situ hybridization and confocal laser scanning microscopy. Using micromanipulation, it was possible to isolate single intracellular L-form cells that following transfer into fresh medium gave rise to pure cultures. In conclusion, the results obtained here provide strong evidence that antibiotic treatment of infected host cells can induce the formation of L-forms from intracellular Listeria monocytogenes. Furthermore, our results suggest that intracellular L-forms persist inside host cells and that they represent viable bacteria, which are still able to grow and proliferate.

Chickensplash! Exploring the health concerns of washing raw chicken.

The Food and Drug Administration recommends against washing raw chicken due to the risk of transferring dangerous food-borne pathogens through splashed drops of water. Many cooks continue to wash raw chicken despite this warning, however, and there is a lack of scientific research assessing the extent of microbial transmission in splashed droplets. Here, we use large agar plates to confirm that bacteria can be transferred from the surface of raw chicken through splashing. We also identify and create a phylogenetic tree of the bacteria present on the chicken and the bacteria transferred during splashing. While no food-borne pathogens were identified, we note that organisms in the same genera as pathogens were transferred from the chicken surface through these droplets. Additionally, we show that faucet height, flow type, and surface stiffness play a role in splash height and distance. Using high-speed imaging to explore splashing causes, we find that increasing faucet height leads to a flow instability that can increase splashing. Furthermore, splashing from soft materials such as chicken can create a divot in the surface, leading to splashing under flow conditions that would not splash on a curved, hard surface. Thus, we conclude that washing raw chicken does risk pathogen transfer and cross-contamination through droplet ejection, and that changing washing conditions can increase or decrease the risk of splashing.

An antimicrobial peptide specifically active against Listeria monocytogenes is secreted by Bacillus pumilus SF214

BackgroundMembers of the Bacillus genus produce a large variety of antimicrobial peptides including linear or cyclic lipopeptides and thiopeptides, that often have a broad spectrum of action against Gram-positive and Gram-negative bacteria. We have recently reported that SF214, a marine isolated strain of Bacillus pumilus, produces two different antimicrobials specifically active against either Staphylococcus aureus or Listeria monocytogenes. The anti-Staphylococcus molecule has been previously characterized as a pumilacidin, a nonribosomally synthesized lipopetide composed of a mixture of cyclic heptapeptides linked to fatty acids of variable length.ResultsOur analysis on the anti-Listeria molecule of B. pumilus SF214 indicated that it is a peptide slightly smaller than 10 kDa, produced during the exponential phase of growth, stable at a wide range of pH conditions and resistant to various chemical treatments. The peptide showed a lytic activity against growing but not resting cells of Listeria monocytogenes and appeared extremely specific being inactive also against L. innocua, a close relative of L. monocytogenes.ConclusionsThese findings indicate that the B. pumilus peptide is unusual with respect to other antimicrobials both for its time of synthesis and secretion and for its strict specificity against L. monocytogenes. Such specificity, together with its stability, propose this new antimicrobial as a tool for potential biotechnological applications in the fight against the dangerous food-borne pathogen L. monocytogenes.

Detection of SHIGA-TOXIN producing E. coli in some retail markets in Egypt using qPCR assay with special reference to serotyping

Background: Shiga toxin-producing Escherichia coli are dangerous foodborne pathogens that represent a severe public health issue worldwide. Raw foods are considered an important source of STEC infection in humans. Objective: In the current study, STEC contamination was investigated in 80 raw foods (chicken, beef, and milk) and water collected from different localities of Greater Cairo using Real-Time PCR. Moreover, the virulence genes of isolates were characterized. Results: STEC was detected in eight samples, (7 beef and 1 chicken), which represent about 10% of the tested samples. Positive beef and chicken samples show the presence of 13 and 2 STEC genes, respectively. Five samples were positive for eaeA (intemin), two samples were positive for stx1 gene and eight samples were positive for stx2 gene. Beef samples reveal the highest incidence of virulence gene stx2 (35%), followed by eaeA (20%), then stx1 (10%). The incidence of STEC was lower in chicken samples and the prevalence of virulence gene was 5% for stx2 and eaeA, respectively. Stx2 gene was the most prevalent subtype identified in beef samples. Serotyping of isolated STEC strains (14) revealed isolation of seven STEC strains belong to O157 serogroup, two strains belong to O111and five strains belong to serogroup O26. Conclusion: The current study concluded that recovery of STEC from raw chicken and beef samples is of important concern.

Rapid detection of trace Salmonella in milk using an effective pretreatment combined with droplet digital polymerase chain reaction

Salmonella is one of the most dangerous food-borne pathogens around the world to cause a threat to humans and it is urgent to develop the rapid detection method of trace Salmonella in food. Although many advanced techniques have been widely applied to shorten the detection time, the pretreatment method usually used of traditional enrichment and plate culturing to separate Salmonella are complicated and time-consuming. Herein, we developed an effective pretreatment method based on in situ enrichment culture with an immunomagnetic separation step, combined with droplet digital polymerase chain reaction (ddPCR) technology to achieve rapid detection of trace Salmonella in milk, which allowed detecting as low as 10−1 CFU/mL level of Salmonella. It took 8 h to perform the entire testing process from pretreatment to ddPCR detection and analysis. The pretreatment method could be a suitable platform integrating with many detection techniques for the rapid detection of trace Salmonella.

Prevalence and Characterization of Extended-Spectrum β-Lactamase-Producing Antibiotic-Resistant Escherichia coli and Klebsiella pneumoniae in Ready-to-Eat Street Foods.

As the global urban populations increase with rapid migration from rural areas, ready-to-eat (RTE) street foods are posing food safety challenges where street foods are prepared with less structured food safety guidelines in small and roadside outlets. The increased presence of extended-spectrum-β-lactamase (ESBL) producing bacteria in street foods is a significant risk for human health because of its epidemiological significance. Escherichia coli and Klebsiella pneumoniae have become important and dangerous foodborne pathogens globally for their relevance to antibiotic resistance. The present study was undertaken to evaluate the potential burden of antibiotic-resistant E. coli and K. pneumoniae contaminating RTE street foods and to assess the microbiological quality of foods in a typical emerging and growing urban suburb of India where RTE street foods are rapidly establishing with public health implications. A total of 100 RTE food samples were collected of which, 22.88% were E. coli and 27.12% K. pneumoniae. The prevalence of ESBL-producing E. coli and K. pneumoniae was 25.42%, isolated mostly from chutneys, salads, paani puri, and chicken. Antimicrobial resistance was observed towards cefepime (72.9%), imipenem (55.9%), cefotaxime (52.5%), and meropenem (16.9%) with 86.44% of the isolates with MAR index above 0.22. Among β-lactamase encoding genes, blaTEM (40.68%) was the most prevalent followed by blaCTX (32.20%) and blaSHV (10.17%). blaNDM gene was detected in 20.34% of the isolates. This study indicated that contaminated RTE street foods present health risks to consumers and there is a high potential of transferring multi-drug-resistant bacteria from foods to humans and from person to person as pathogens or as commensal residents of the human gut leading to challenges for subsequent therapeutic treatments.

Rapid nucleic acid detection of Escherichia coli O157:H7 based on CRISPR/Cas12a system

Escherichia coli O157:H7 ( E. coli O157:H7) is one of the most dangerous foodborne pathogens causing severe illnesses in the elderly, children and immunocompromised people. Traditional methods could not meet the detection requirements of high speed, sensitivity, and specificity. The clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostic is a novel high sensitivity and specificity detection method. In this study, a rapid nucleic acid of Escherichia coli O157:H7 was detected using rfbE gene based on CRISPR/Cas12a system. The limit of detection for DNA and bacterial concentrations was 0.9 pg/μL and 6.5 × 10 4 CFU/mL, respectively. Furthermore, when the initial bacterial inoculum was 14 CFU/mL in the ground beef sample, the target was detected after 4 h of culture through Metal Organic Framework immunomagnetic beads (Fe 3 O 4 @PDA@UiO-66-NH 2 ) enrichment. • A rapid detection method based on CRISPR/Cas12a system to detect E. coli O157: H7. • CRISPR/Cas12a system was more accurate and better than g-MIRA and RT-PCR. • CRISPR/Cas12a system demonstrated the limit of 14 CFU⋅mL −1 in beef within 4h. • The detection time was 1 h earlier enriched by immunomagnetic beads.

An Aggregation-Induced Emission Material Labeling Antigen-Based Lateral Flow Immunoassay Strip for Rapid Detection of Escherichia coli O157:H7.

Escherichia coli O157:H7 (E. coli O157:H7) is a dangerous foodborne pathogen, mainly found in beef, milk, fruits, and their products, causing harm to human health or even death. Therefore, the detection of E. coli O157:H7 in food is particularly important. In this paper, we report a lateral flow immunoassay strip (LFIS) based on aggregation-induced emission (AIE) material labeling antigen as a fluorescent probe for the rapid detection of E. coli O157:H7. The detection sensitivity of the strip is 105 CFU/mL, which is 10 times higher than that of the colloidal gold test strip. This method has good specificity and stability and can be used to detect about 250 CFU of E. coli O157:H7 successfully in 25 g or 25 mL of beef, jelly, and milk. AIE-LFIS might be valuable in monitoring food pathogens for rapid detection.

Fe3O4@silica nanoparticles for reliable identification and magnetic separation of Listeria monocytogenes based on molecular-scale physiochemical interactions

Listeria monocytogenes (L. monocytogenes) is one of the top five dangerous foodborne pathogens which widely exists in most raw food and has approximately 30 % mortality rate in high-risk groups. Food safety caused by foodborne pathogens is still a major problem faced by humans in all world. The conventional analytical methods currently used involve complex bacteriological tests and usually take several days for incubation and analysis. Thus, in order to prevent the spread of disease, the development of a detection method with high speed, high accuracy and sensitivity is urgent and necessary. Herein, we developed an approach for the identification and magnetic capture of L. monocytogenes by using core@shell Fe3O4@silica nanoparticles terminated with hydroxyl or amine groups. Our results show that both amine- and hydroxyl-terminated Fe3O4@silica core@shell nanoparticles functionalized with specific antibodies, present 95.2 %±6.2 % and 98.6 %±0.3 % capture efficacies, respectively. However, without conjugating the specific antibodies, the hydroxyl-terminated Fe3O4@silica nanoparticles exhibit 17.6 %±1.6 % efficacy, while the amine-terminated one remains 93.2 %±9.2 % capture efficiency ascribed to the high affinity. This study quantitatively uncovers the specific and non-specific recognitions relevant to the molecular-scale physiochemical interactions between the microorganisms and the functionalized particles, and the results from this work can be generalized and extended to other bacterial species by changing antibodies, also have important implications in developing advanced analytic methods.

In silico identification of novel PrfA inhibitors to fight listeriosis: A virtual screening and molecular dynamics studies

Listeria monocytogenes is considered to be one of the most dangerous foodborne pathogens as it can cause listeriosis, a life-threatening human disease. While the incidence of listeriosis is very low its fatality rate is exceptionally high. Because many multi-resistance Listeria monocytogenes strains that do not respond to conventional antibiotic therapy have been recently described, development of new antimicrobials to fight listeriosis is necessary. The positive regulatory factor A (PrfA) is a key homodimeric transcription factor that modulates the transcription of multiple virulence factors which are ultimately responsible of Listeria monocytogenes’ pathogenicity. In the present manuscript we describe several new potential PrfA inhibitors that were identified after performing ligand-based virtual screening followed by molecular docking calculations against the wild-type PrfA structure. The three top-scored drug-likeness inhibitors bound to the wild-type PrfA structure were further assessed by Molecular Dynamics (MD) simulations. Besides, the three top-scored inhibitors were docked into a constitutive active apoPrfA mutant structure and the corresponding complexes were also simulated by MD. According to the obtained data, PUBChem 87534955 (P875) and PUBChem 58473762 (P584) may not only bind and inhibit wild-type PrfA but the aforementioned apoPrfA mutant as well. Therefore, P875 and P584 might represent good starting points for the development of a completely new set of antimicrobial agents to treat listeriosis.

An Overview of the Elusive Passenger in the Gastrointestinal Tract of Cattle: The Shiga Toxin Producing Escherichia coli.

For approximately 10,000 years, cattle have been our major source of meat and dairy. However, cattle are also a major reservoir for dangerous foodborne pathogens that belong to the Shiga toxin-producing Escherichia coli (STEC) group. Even though STEC infections in humans are rare, they are often lethal, as treatment options are limited. In cattle, STEC infections are typically asymptomatic and STEC is able to survive and persist in the cattle GIT by escaping the immune defenses of the host. Interactions with members of the native gut microbiota can favor or inhibit its persistence in cattle, but research in this direction is still in its infancy. Diet, temperature and season but also industrialized animal husbandry practices have a profound effect on STEC prevalence and the native gut microbiota composition. Thus, exploring the native cattle gut microbiota in depth, its interactions with STEC and the factors that affect them could offer viable solutions against STEC carriage in cattle.

Efficacy of household washing pre-treatments and cooking methods for reduction of Listeria monocytogenes in artificially contaminated chicken offal

Consumption of chicken offal is common and famous among Malaysians as it is often served as one of the side dishes with rice. Chicken offal can be a potential source of Listeria monocytogenes because slaughtered animals are recognized as a reservoir for foodborne pathogens. L. monocytogenes is a dangerous foodborne pathogen which can cause severe foodborne listeriosis with high fatality rate. This study aimed to determine the efficacy of different washing pre-treatment and cooking methods to reduce L. monocytogenes in artificially contaminated chicken offal. All the washing pre-treatments (dip treatment in different water sources and wash treatment with different water flow rates) showed significant reduction of the pathogen (p&lt;0.05) when the inoculated samples were treated from 2 mins onwards. Washing the inoculated samples under the water flow rate of 2 L/min was the most effective way to reduce the number of L. monocytogenes (approximately 1.97 log reduction after washing for 10 mins). For heat treatment study, deep-frying was the most effective cooking method followed by boiling and pan-frying to reduce L. monocytogenes where all L. monocytogenes cells (7.91 log10 CFU/g) were killed within 45 s under deep-frying treatment. Overall, the study indicated that washing under running tap water (2 L/min) and deep-frying was effective in reducing and controlling the microbial populations during food preparation. The findings from this study can serve as a safe preparation step and cooking guideline. It is necessary to implement safe steps in food handling practices among food handlers to minimize the risk of foodborne infection.