Ready-to-eat Meat Products Research Articles

Molecular detection of enterotoxins in multidrug resistant Aeromonas from ready to eat foods in North Western Himalayas: Public health significance

Aeromonas spp. are normal inhabitants of aquatic environments and are emerging foodborne bacterial pathogens. Aeromonas spp. contamination is frequent in ready-to-eat (RTE) seafood and can also occur in products prepared from milk or meat. The study determined the enterotoxin and antimicrobial susceptibility profiles of Aeromonas spp. isolates recovered from RTE milk products (n = 105), RTE meat/fish products (n = 40) and drinking water (n = 60) samples collected from tourist places in Himachal Pradesh, India, in northwestern Himalayas. 7.3 % (16/220) samples were found contaminated with Aeromonas spp. These isolates were identified as A. hydrophila (31.3 %), A. schubertii (25.0 %), A. sobria (25.0 %) and A. veronii (18.8 %). Aeromonas spp. contamination was significantly higher (14.3 %, 15/105, p = 0.0001) in RTE milk products. The contamination levels for water samples were 1.7 % whereas none of the tested RTE meat or fish products yielded Aeromonas spp. Among RTE milk products, contamination was significantly higher in paneer (South Asian soft cheese) (26.1 %, p = 0.0027) and cream (25.0 %, p = 0.046) based RTE foods. All isolates carried alt (361 bp), encoding a cytotonic heat-labile enterotoxin. Ampicillin resistance was 100 % and high levels (>30 %) of resistance were recorded for amoxicillin/clavulanic acid, amikacin, cefotaxime and ceftazidime. Six (37.5 %) isolates were multi drug resistant (MDR), showing resistance to aminoglycosides, cephams and penicillins. Isolation of alt carrying MDR isolates from RTE foods indicates that Aeromonas spp. can be potential foodborne public health threat in northwestern Himalayas.

Antimicrobial resistance of E. coli strains in ready-to-eat red meat products in Nakuru County, Kenya

The demand for Ready-To-Eat (RTE) meat products is rising especially to the busy urban dwellers. Handling, processing, and selling methods of RTE contaminate them with pathogens. However, there is lack of evidence of the risk of antimicrobial resistance (AMR) of the pathogens. In this study, 105 RTE meat products were sampled across Nakuru County and assessed for Escherichia coli load, antimicrobial resistance (AMR), and presence of AMR genes. All the sampled meat products were contaminated with coliforms and E. coli but levels differed significantly (p < 0.05) with location of sample collection and type of RTE. Antimicrobial susceptibility test results of 30 E. coli isolates indicated high prevalence of the isolates’ resistance to co-trimoxazole, tetracycline, streptomycin, and ampicillin at 80%, 73%, 67%, and 67%, respectively. Antibiotic susceptibility of the isolates was highest towards ciprofloxacin and amikacin at 100% and 80%, respectively. All the 30 E. coli isolates showed 14 different AMR patterns, where each isolate was resistant to at least 2 antibiotics; a multiple antibiotic resistance (MAR) index of greater than 0.2. Meat samples collected from one sampling location, Salgaa had the highest number of multi-drug resistant E. coli isolates (88.9%). Molecular identification of AMR genes in four MAR isolates showed that tetA (for tetracycline resistance) and sul1 (for co-trimoxazole resistance) genes were present in all (100.0%) the isolates, while blaTEM (for ampicillin resistance) and strA (for streptomycin) genes were both present in two isolates. The four isolates were not E. coli O157 as confirmed by PCR for the O157 lipopolysaccharide O-antigen synthesis gene rfbE-O157. This study demonstrated the presence of MAR E. coli in RTE red meat products sold in Nakuru County, which is a human and animal public health concern, hence a need to urgently regulate and monitor the use of antimicrobials in animals.

Ready-to-eat Meat Plant Characteristics Associated with Food Safety Deficiencies During Regulatory Compliance Audits, Ontario, Canada

Food safety deficiencies in ready-to-eat (RTE) meat processing plants can increase foodborne disease risks. The purpose of this study was to identify common deficiencies and factors related to improved food safety performance in RTE meat plants in Ontario. Routine food safety audit records for licensed provincial free-standing meat processing plants (FSMPs) and abattoirs that process RTE meats were obtained and analyzed in Ontario, Canada, from 2015 to 2019. A Bayesian regression analysis was conducted to examine the association between selected plant characteristics and two outcomes: overall audit rating (pass vs. conditional pass or fail) and individual audit item fail rate. The audit rating was examined in a logistic model, while the audit item fail rate was evaluated in a negative binomial model. The majority (87.7%, n = 800/912) of audits resulted in a pass rating (compared to conditional pass or fail). The mean number of employees per plant, among 200/204 plants with employee data available, was 11.6 (SD = 20.6, range = 1–200). For the logistic regression model, FSMPs were predicted to have a much higher probability of passing audits than abattoirs (32.0% on average, with a 95% credible interval [CI] of 13.8–52.8%). The number of plant employees, water source (municipal vs. private), and types of RTE meat products produced had little to no consistent association with this outcome. The negative binomial model predicted a −0.009 points lower fail rate, on average, for audit items among FSMPs than abattoirs (95% CI: −0.001, −0.018). Meat plants producing jerky had a higher audit item fail rate compared to those that did not produce such products. The other investigated variables had little to no association with this outcome. The results found in this study can support and guide future inspection, audit and outreach efforts to reduce foodborne illness risks associated with RTE meats.

Extending The Shelf Life of Ready-To-Eat (RTE) Meat Product by Using Turmeric and Red Ginger as Film Coating of Active Packaging

The high demand for ready-to-eat (RTE) meat products is attributed to their convenience, safe, and healthy properties. The high nutritional content presence in the RTE meat product promotes the presence and growth of microbial pathogens such as Listeria monocytogenes, Escherichia coli, and Salmonella spp. It is considered to be the post-process contamination that is responsible for the shortening of a product’s shelf life which leads to spoilage or foodborne diseases. The aim of this systematic review is to develop and summarize the use of red ginger and turmeric bioactive compounds as antimicrobial materials to ensure their quality and extend the shelf-life of RTE beef rendang products. Thus, the current studies of coating technology of bioactive compounds and vacuum-sealed packaging are considered to be combined strategies that develop a more robust active packaging system. In order to gain a better understanding of this research field, a literature search was performed using the electronic databases Oxford Journals, Google Scholar, SAGE Journals, ScienceDirect, and Taylor &amp; Francis which describes 26 primary studies. The findings state that the enhanced active packaging system by using bioactive compounds was associated with a significant prolongation of various RTE meat product’s shelf-life of up to 30 days of storage at room temperature. Moreover, the vacuum-sealed packaging in a retort pouch is also considered to improve the food safety environment against microbial contamination

Natural Antimicrobials for Listeria monocytogenes in Ready-to-Eat Meats: Current Challenges and Future Prospects

Listeria monocytogenes, an intra-cellular, Gram-positive, pathogenic bacterium, is one of the leading agents of foodborne illnesses. The morbidity of human listeriosis is low, but it has a high mortality rate of approximately 20% to 30%. L. monocytogenes is a psychotropic organism, making it a significant threat to ready-to-eat (RTE) meat product food safety. Listeria contamination is associated with the food processing environment or post-cooking cross-contamination events. The potential use of antimicrobials in packaging can reduce foodborne disease risk and spoilage. Novel antimicrobials can be advantageous for limiting Listeria and improving the shelf life of RTE meat. This review will discuss the Listeria occurrence in RTE meat products and potential natural antimicrobial additives for controlling Listeria.

LISTERIA MONOCYTOGENES IN READY-TO-EAT CHICKEN PRODUCTS, THEIR ANTIBIOTIC RESISTANCE AND VIRULENCE GENES

Ready-to-eat (RTE) meat products are food items that are extremely popular worldwide. Albeit documented with the alarming prevalence of pathogenic multidrug-resistant Listeria species in these food items worldwide, studies from the perspective of Bangladesh are absent. This study was devised with the aim to detect pathogenic Listeria monocytogenes in some of the most popular RTE meat products in Dhaka, Bangladesh. Thirty-nine such samples were investigated using biochemical tests and the Polymerase Chain Reaction (PCR) analysis. Following confirmatory tests and detection of Listeria species, the isolates were subjected to the Kirby-Bauer disc diffusion test to investigate their antibiotic-susceptibility patterns against some of the most commonly used antibiotics to treat listeriosis – the infection caused by Listeria. Five Listeria species were detected using biochemical and PCR tests. This constituted an overall prevalence rate of 12.8% (n = 39). Four out of the five Listeria species were concluded to be L. monocytogenes, while the remaining one was an L. innocua isolate. PCR analyses revealed all four of the L. monocytogenes isolates to have the virulence genes hlyA, plcB and actA, although no polymorphism was observed for these genes. Despite the presence of these pathogenic genes, antibiotic susceptibility tests showed promising results as some of the most commonly prescribed drugs against listeriosis were highly effective against the isolates. Even though the isolates showed little to no antibiotic resistance against the antibiotics used in the study, the presence of three virulence genes in all four L. monocytogenes isolates is still a cause for concern. Even more so, the prevalence of these pathogenic strains in a food item that is increasing in popularity in a country like Bangladesh, where awareness and surveillance against listeriosis is limited, can have dire consequences should an outbreak occurs. Bioresearch Commu. 9(1): 1160-1169, 2023 (January)

Dynamic Changes of Bacterial Communities and Microbial Association Networks in Ready-to-Eat Chicken Meat during Storage.

Ready-to-eat (RTE) chicken is a popular food in China, but its lack of food safety due to bacterial contamination remains a concern, and the dynamic changes of microbial association networks during storage are not fully understood. This study investigated the impact of storage time and temperature on bacterial compositions and microbial association networks in RTE chicken using 16S rDNA high-throughput sequencing. The results show that the predominant phyla present in all samples were Proteobacteria and Firmicutes, and the most abundant genera were Weissella, Pseudomonas and Proteus. Increased storage time and temperature decreased the richness and diversity of the microorganisms of the bacterial communities. Higher storage temperatures impacted the bacterial community composition more significantly. Microbial interaction analyses showed 22 positive and 6 negative interactions at 4 °C, 30 positive and 12 negative interactions at 8 °C and 44 positive and 45 negative interactions at 22 °C, indicating an increase in the complexity of interaction networks with an increase in the storage temperature. Enterobacter dominated the interactions during storage at 4 and 22 °C, and Pseudomonas did so at 22 °C. Moreover, interactions between pathogenic and/or spoilage bacteria, such as those between Pseudomonas fragi and Weissella viridescens, Enterobacter unclassified and Proteus unclassified, or those between Enterobacteriaceae unclassified and W.viridescens, were observed. This study provides insight into the process involved in RTE meat spoilage and can aid in improving the quality and safety of RTE meat products to reduce outbreaks of foodborne illness.

Isolation, identification, and antibiogram studies of Escherichia coli from ready-to-eat foods in Mymensingh, Bangladesh.

Background and Aim:Ready-to-eat (RTE) foods are widely used at home, restaurants, and during festivals in Bangladesh. So it is very important to investigate possible microbial contamination in RTE foods. Therefore, this study aimed to determine the total coliform count (TCC), isolate, identify, and characterize the Escherichia coli in RTE foods. The antimicrobial sensitivity of E. coli obtained from RTE foods was also performed using 12 commonly used antibiotics.Materials and Methods:A total of 100 RTE food samples were collected aseptically and comprised of ten samples each: Burger, pizza, sandwich, chicken roll, chicken meat loaf, chicken fry, salad vegetable, ice-cream, yogurt, and milkshake sold in Mymensingh City. Samples were inoculated onto Eosin methylene blue agar and incubated at 37°C for 24 h. Isolation and identification of bacteria were performed based on cultural, staining, and biochemical properties, followed by a polymerase chain reaction.Results:The TCC in Chicken meat loaf, burger, pizza, sandwich, salad vegetable ice-cream, and yogurt samples were 3.57 ± 0.96, 3.69 ± 0.08, 3.50 ± 0.60, 2.60 ± 0.20, 4.09 ± 0.29, 4.44 ± 0.25, and 3.14 ± 0.30 mean log colony-forming units ± standard deviation/mL, respectively. The study found a higher prevalence of E. coli in RTE salad vegetable products than in RTE meat and milk products. Forty percent of the mixed vegetable salad samples showed positive results for E. coli. Whereas E. coli prevalence in RTE meat and milk products was 20% and 16.7%, respectively. All the 21 isolates were subjected to antibiotic susceptibility test against 12 different antibiotics. It was observed that 46.1% were susceptible, 16.6% were intermediate, 46.1% were resistant, and 47.6% were multidrug-resistant (MDR) among seven different antibiotic classes. E. coli isolates were resistant to cephalexin, ceftazidime, oxytetracycline, and ampicillin and sensitive to gentamycin, followed by kanamycin, ceftriaxone, colistin, and enrofloxacin.Conclusion:The study revealed that RTE foods are a serious issue from a public health point of view. To achieve a safer level of E. coli in RTE foods sold for human consumption, public food outlets must improve hygienic and good production procedures. Moreover, MDR E. coli in these foods pose serious public health threats.

Strategies for Biocontrol of Listeria monocytogenes Using Lactic Acid Bacteria and Their Metabolites in Ready-to-Eat Meat- and Dairy-Ripened Products.

Listeria monocytogenes is one of the most important foodborne pathogens. This microorganism is a serious concern in the ready-to-eat (RTE) meat and dairy-ripened products industries. The use of lactic acid bacteria (LAB)-producing anti-L. monocytogenes peptides (bacteriocins) and/or lactic acid and/or other antimicrobial system could be a promising tool to control this pathogen in RTE meat and dairy products. This review provides an up to date about the strategies of use of LAB and their metabolites in RTE meat products and dairy foods by selecting the most appropriate strains, by analysing the mechanism by which they inhibit L. monocytogenes and methods of effective application of LAB, and their metabolites in these kinds of products to control this pathogen throughout the processing and storage. The selection of LAB with anti-L. monocytogenes activity allows to dispose of effective strains in meat and dairy-ripened products, achieving reductions form 2–5 logarithmic cycles of this pathogen throughout the ripening process. The combination of selected LAB strains with antimicrobial compounds, such as acid/sodium lactate and other strategies, as the active packaging could be the next future innovation for eliminating risk of L. monocytogenes in meat and dairy-ripened products.

Antibiotic resistance in the pathogenic foodborne bacteria isolated from raw kebab and hamburger: phenotypic and genotypic study

BackgroundIn recent years, interest in the consumption of ready-to-eat (RTE) food products has been increased in many countries. However, RTE products particularly those prepared by meat may be potential vehicles of antibiotic-resistance foodborne pathogens. Considering kebab and hamburger are the most popular RTE meat products in Iran, this study aimed to investigate the prevalence and antimicrobial resistance of common foodborne pathogens (Escherichia coli, Salmonella spp., Staphylococcus aureus, and Listeria monocytogenes) in raw kebab and hamburger samples collected from fast-food centers and restaurants. Therefore, total bacterial count (TBC), as well as the prevalence rates and antibiogram patterns of foodborne pathogens in the samples were investigated. Also, the presence of antibiotic-resistance genes (blaSHV, blaTEM,blaZ, and mecA) was studied in the isolates by PCR.ResultsThe mean value of TBC in raw kebab and hamburger samples was 6.72 ± 0.68 log CFU/g and 6.64 ± 0.66 log CFU/g, respectively. E. coli had the highest prevalence rate among the investigated pathogenic bacteria in kebab (70%) and hamburger samples (48%). Salmonella spp., L. monocytogenes, and S. aureus were also recovered from 58, 50, and 36% of kebab samples, respectively. The contamination of hamburger samples was detected to S. aureus (22%), L. monocytogenes (22%), and Salmonella spp. (10%). In the antimicrobial susceptibility tests, all isolates exhibited high rates of antibiotic resistance, particularly against amoxicillin, penicillin, and cefalexin (79.66–100%). The blaTEM was the most common resistant gene in the isolates of E. coli (52.54%) and Salmonella spp. (44.11%). Fourteen isolates (23.72%) of E. coli and 10 isolates (29.41%) of Salmonella spp. were positive for blaSHV. Also, 16 isolates (55.17%) of S. aureus and 10 isolates (27.27%) of L. monocytogenes were positive for mecA gene.ConclusionsThe findings of this study showed that raw kebab and hamburger are potential carriers of antibiotic-resistance pathogenic bacteria, which can be a serious threat to public health.

Presence of Listeria monocytogenes in Ready-to-Eat Meat Products Sold at Retail Stores in Costa Rica and Analysis of Contributing Factors

Listeria monocytogenes is a pathogenic bacterium associated with ready-to-eat (RTE) meat products sold at the retail level. The objective of this research was to determine the prevalence of L. monocytogenes in RTE meat products sold at retail in Costa Rica and to study the factors associated with the levels of contamination; analyzed factors include hygienic practices within stores (cutting techniques and microbial contamination of products) and the behavior of the isolates (persistence against antimicrobials and transfer potential). A total of 190 samples of RTE meat products were collected and analyzed for the presence of coliforms and Listeria spp. Isolates of L. monocytogenes were then evaluated in terms of resistance to disinfectants (quaternary ammonium compound [QAC] and chlorine) and their transfer potential from food contact surfaces (knife and cutting boards). Overall Listeria spp. prevalence was 37.4% (71 of 190); Listeria innocua was present in 32.1% (61 of 190) of the products, and L. monocytogenes was found in just 2.6% (5 of 190) of the samples. Most contaminated samples were cut with a knife at the moment of purchase (44.2%). When analyzing practices within the stores, it was observed that L. monocytogenes transfer from inoculated knife to salchichón was higher for samples cut at the beginning of the experiment. In addition, L. monocytogenes transfer from inoculated cutting boards was independent of the number of slices but contamination from plastic was higher than wood. Regarding L. monocytogenes resistance to disinfectants, average reductions of 2.6 ± 1.1 log CFU/mL were detected after 6 min of exposure to 200 ppm of chlorine; however, chlorine resistance varied among the strains. Prevalence of L. monocytogenes in RTE meat products sold at retail could be associated with handling practices within the stores; further studies are necessary to estimate the impact of these practices on the overall risk for consumers.

Predicting the effect of salt on heat tolerance of Listeria monocytogenes in meat and fish products

Listeria monocytogenes is a potentially fatal foodborne pathogen that can be found in various ready-to-eat (RTE) products. It tolerates adverse conditions such as high salt concentrations and refrigerated storage, thus, the elimination of the pathogen in food processing often relies on heat processing. The objective of this study was to create a model to predict the effect of salt on heat tolerance of L. monocytogenes in meat and seafood products during heat treatments conducted at 57 to 65 °C to reduce numbers by ≥3 log10 cycles. Salt concentrations, up to 6% in the water phase (WPS%), were applied to cover a variety of lightly salted RTE meat and seafood products. The experimental work involved samples of ground pork tenderloin, ground chicken breast fillet and skinned, ground salmon fillet adjusted to different WPS% i.e., 3.6 and 5.2 WPS% for pork samples, 2.0, 3.0, 3.5 and 6.0 WPS% for chicken samples and 3.0 and 6.0 WPS% for salmon samples. All samples were inoculated with late-stationary phase L. monocytogenes cultures. For pork samples, a two-strain mixture of a pork isolate (MS22254) and an environmental isolate (MS22246) was applied. For chicken and salmon samples, a seafood isolate (MS22258) and isolate MS22246 was applied as single cultures. Samples were vacuum-packed in sterile bags, immerged in water bath, and held at constant temperatures of 57, 60 and 65 °C for pork samples and 58, 61 and 62.5 °C for chicken and salmon samples. For survivor curves, where at least 3 log10-reduction were obtained, heat tolerance was expressed as decimal reduction times, D-values. D-values were observed to increase with increasing WPS%. The effect of salt on heat tolerance of L. monocytogenes was defined as the relative increase (RI-value) in D-value obtained when salt had been added to the food. The effect of WPS% on RI-values was independent of heating temperatures, foods and strains. For secondary modelling, RI-values were transformed using the natural logarithm, ln(RI) and fitted to a linear model as a function of WPS%. Model validation, with 56 independent values collected from the scientific literature, resulted in bias and accuracy factors of 0.89 and 1.26, respectively, suggesting acceptable performance with tendency to slightly under-predict. The developed predictive model can be used to guide the design of heat processes for manufacturers of lightly preserved and mildly processed meat and seafood products requiring more than 3 log10 reduction of L. monocytogenes to ensure safety.

First Report of a Foodborne Salmonella enterica Serovar Gloucester (4:i:l,w) ST34 Strain Harboring bla CTX-M- 55 and qnrS Genes Located in IS26-Mediated Composite Transposon.

Extended-spectrum β-lactamases (ESBLs) production and (fluoro)quinolone (FQ) resistance among Salmonella pose a public health threat. The objective of this study was the phenotypic and genotypic characterization of an ESBL-producing and nalidixic acid-resistant Salmonella enterica serovar Gloucester isolate (serotype 4:i:l,w) of sequence type 34 (ST34) from ready-to-eat (RTE) meat products in China. Whole-genome short and long read sequencing (HiSeq and MinION) results showed that it contained blaCTX–M–55, qnrS1, and tetB genes, with blaCTX–M–55 and qnrS1 located in chromosomal IS26-mediated composite transposon (IS26–qnrS1–IS3–Tn3–orf–blaCTX–M–55–ISEcp1–IS26). The same genetic structure was found in the chromosome of S. enterica subsp. enterica serovar Typhimurium strain and in several plasmids of Escherichia coli, indicating that the IS26-mediated composite transposon in the chromosome of S. Gloucester may originate from plasmids of E. coli and possess the ability to disseminate to Salmonella and other bacterial species. Besides, the structural unit qnrS1–IS3–Tn3–orf–blaCTX–M–55 was also observed to be linked with ISKpn19 in both the chromosomes and plasmids of various bacteria species, highlighting the contribution of the insertion sequences (IS26 and ISKpn19) to the co-dissemination of blaCTX–M–55 and qnrS1. To our knowledge, this is the first description of chromosomal blaCTX–M–55 and qnrS in S. Gloucester from RTE meat products. Our work expands the host range and provides additional evidence of the co-transfer of blaCTX–M–55 and qnrS1 among different species of Salmonella through the food chain.

Occurrence of Listeria monocytogenes in Ready-to-Eat Meat and Poultry Product Verification Testing Samples from U.S. Department of Agriculture–Regulated Producing Establishments, 2005 through 2017

Ready-to-eat (RTE) meat and poultry product samples collected between 2005 and 2017 from RTE-producing establishments for the U.S. Department of Agriculture, Food Safety and Inspection Service (FSIS) ALLRTE/RTEPROD_RAND (random) and RTE001/RTEPROD_RISK (risk-based) sampling projects were tested for Listeria monocytogenes (Lm). Data for 45,897 ALLRTE/RTEPROD_RAND samples collected from 3,607 distinct establishments and 112,347 RTE001/RTEPROD_RISK samples collected from 3,283 distinct establishments were analyzed for the presence of Lm. These data were also analyzed based upon the percentages of establishments with positive samples, annual production volume, sanitation control alternatives, geographic location, and season or month of sample collection. Results revealed low occurrence of Lm-positive samples from the random and risk-based sampling projects, with 152 (0.33%) positive samples for ALLRTE/RTEPROD_RAND and 403 (0.36%) positive samples for RTE001/RTEPROD_RISK. The percentage of positive samples significantly decreased over time, from about 0.7% in 2005 and 2006 to about 0.2% in 2017 (P < 0.05). From 2005 to 2017, 3.9% of establishments sampled under the ALLRTE/RTEPROD_RAND sampling project had at least one Lm-positive sample. Similarly, 10.0% of establishments sampled under the RTE001/RTEPROD_RISK sampling project had at least one positive sample. Samples positive for Lm were found in all geographic regions in all months. Thus, in 13 years of RTE product sampling in FSIS-regulated establishments (2005 through 2017), <0.4% of samples were positive for Lm in both risk-based and random sampling projects. The low prevalence of Lm in these products suggests that the combination of FSIS policies and industry practices may be effective for controlling Lm contamination. Information obtained from these sampling projects is relevant to the ongoing prevention of foodborne Lm illnesses from RTE meat and poultry products.

Microbiological quality of ready-to-eat food products in southern Taiwan

This study was to assess the microbiological quality of commercial ready-to-eat (RTE) food products sold in southern Taiwan. A total of 126 RTE food samples, including staple, meat, seafood, and vegetarian food products, were purchased from traditional markets, supermarkets, and warehouse stores. These foods were kept at refrigerator, room temperature, or hot stored at the time of sale. Aerobic plate count (APC), coliform, Escherichia coli, and Staphylococcus aureus were evaluated. APC in excess of 5 log CFU/g was obtained in traditional markets (27 samples), supermarkets (20 samples), and warehouse stores (15 samples). Seafood products were the most contaminated compared to staple products, meat products, or vegetarian foods. The highest incidence of APC greater than 5 log CFU/g was detected from food products stored at room temperature. Refrigerator stored food products were the second incidence, followed by hot kept food products. No significant differences were found for coliform and E. coli among the various markets or food types (p > 0.05). RTE food products sold in the traditional market, supermarkets, and warehouse stores contaminated with S. aureus were 19.0%, 12.7%, and 9.5%, respectively. The percentage of samples over-contaminated with S. aureus was 15.9% (seafood), 9.5% (staple and meat products), and 6.3% (vegetarian food products). RTE food products stored at room temperature had the highest contamination of S. aureus, followed by refrigerator and hot stored food products (p < 0.05).

Occurrence and Characteristics of Listeria monocytogenes in Ready-to-Eat Meat Products in Poland

Listeria monocytogenes is a potential hazard for food safety and therefore for public health. The aim of the present study was to determine the prevalence and characteristics of L. monocytogenes in Polish ready-to-eat (RTE) meat products for retail sale. Among the 184,439 food samples collected within the framework of a national official control and monitoring program, only 0.3% were positive for L. monocytogenes. A significant group of products that did not meet the criteria were RTE meat products. This group accounted for 40% of all noncompliant samples. Seventy L. monocytogenes isolates from these RTE meat products (meat, sausages, and delicatessen products with meat) were examined. The majority of the tested isolates (51%) belonged to serogroup 1/2a-3a followed by 1/2c-3c (21%), 1/2b-3b-7 (14%), and 4ab-4b-4d-4e (13%). Serogroup 4a-4c was not present among the tested isolates. All L. monocytogenes isolates harbored the virulence-associated genes inlA, inlC, inlJ, and lmo2672. The llsX marker was detected in 12 (17%) of the 70 isolates. Ampicillin resistance was the most common resistance phenotype and was identified in 83% of the L. monocytogenes isolates. A low incidence of resistance to amoxicillin-clavulanic acid (6% of isolates) was also detected. All L. monocytogenes isolates were susceptible to chloramphenicol, gentamicin, ciprofloxacin, meropenem, sulfamethoxazole-trimethoprim, tetracycline, and erythromycin. This work provides useful information regarding contamination of RTE meat products with L. monocytogenes, which may have implications for food safety risks.

Multisite survey of bacterial contamination in ready-to-eat meat products throughout the cooking and selling processes in urban supermarket, Nanjing, China.

ObjectiveReady‐to‐eat (RTE) meat is a kind of popular instant food easily contaminated by microbes, which is one of the causes of foodborne diseases. This study analyzes the possible sources of RTE food bacterial contamination during processing and subsequent selling.MethodSamples of eight kinds of RTE meat were collected from four supermarkets in Nanjing, China. The knives, chopping boards, trays(containers of food), clamps, air, water, and hands of the sales staff were sampled, and the enumeration of aerobic plate count and total coliforms and pathogenic bacteria was performed.ResultsThe survey revealed that poor hygienic levels was the causes that RTE meat products were contaminated by bacteria at different levels. With regard to pathogen, the incidences of Salmonella spp. and Staphylococcus aureus were 4.2% and 2.1%, respectively. These results also revealed that the bacterial contamination of RTE food was caused by the air, as well as clamps, chopping boards, knives, trays, and hands of the operators. The total number of aerobic colonies were positively correlated with the amount of RTE food in one pot (r = .87728, p = .0217), and negatively correlated with the maximum temperature in the center of the meat (r = −.81633, p = .0475).ConclusionThe high number of bacteria in RTE foods indicates potential food safety risks and the need to improve the health of supermarket sales staff. The most important thing is to determine how to raise hygiene awareness of employees through food safety education. Meanwhile, a comprehensive set of regulations on hand cleaning and disinfection should be developed to facilitate public health and reduce foodborne illness caused by the consumption of RTE food.

Bacillus cereus: public health burden associated with ready-to-eat foods in Himachal Pradesh, India.

The study determined incidence, enterotoxigenecity and antimicrobial susceptibility profiles of Bacillus cereus isolated from ready-to-eat (RTE) milk products (n = 80), RTE meat products (n = 40), beverages (n = 40) and water samples (n = 60, from food preparing and serving outlets/restaurants) collected from eight different tourist places of Himachal Pradesh. 11.4% (25/220) samples were contaminated with Bacillus and isolates were identified as B. cereus (76.0%, n = 19), B. alvei (12.0%, n = 3), B. polymyxa (8.0%, n = 2) and B. firmus (4.0%, n = 1) by conventional and molecular methods. B. cereus incidence was highest in cheese based foods (25.0%) followed by vegetable soups (16.7%), khoa based foods (14.0%), milk based beverages (10.5%), paneer based foods (8.6%), cream based foods (8.3%) and water (8.3%) samples. Multiplex polymerase chain reaction detected enterotoxigenic genes only in B. cereus isolates. nhe complex (encoding non-haemolytic enterotoxins, ABC) genes were detected only in B. cereus isolates. 57.6% (11/19), 36.8% (7/19) and 5.3% (1/19) harboured all three (nheA, nheB, nheC), two (nheB, nheC) and one (nheC) nhe gene, respectively. Among hbl complex genes (encoding haemolytic enterotoxins CAD), only hblC (36.8%, 7/19)was detected. Incidence B. cereus cytK (encoding cytotoxin enterotoxin) was 52.6% (10/19). Each B. cereus isolate harboured two or more enterotoxigenic genes. Seven isolates had at least one gene from haemolytic and non-haemolytic complexes along with cytK. High levels (> 50%) of antimicrobial resistance were recorded for penicillin, amoxicillin, ampicillin cefixime and ceftazidine in tested B. cereus isolates. Two isolates were identified as multidrug resistant isolates with resistance to ≥ 3 antibiotic classes.

Development of a multiplex real-time PCR to differentiate the four major Listeria monocytogenes serotypes in isolates from meat processing plants

Listeria monocytogenes is an important foodborne pathogen, causative agent of listeriosis. The epidemiology and persistence of this bacterium in meat processing plants may be related to its serotype, so it is of utmost importance to carry out a correct differentiation of L. monocytogenes serotypes. The objective of this study was to develop a unique quadruplex real-time quantitative PCR (qPCR) method able to differentiate the four most predominant and worrying L. monocytogenes serotypes (1/2a, 1/2b, 1/2c and 4b) in isolates from meat processing plants and ready-to-eat (RTE) dry-cured meat products. The design of specific primers and probes was based on the lmo0737, lmo0308, ORFC (locus genomically equivalent to gltA-gltB) and ORF2110 genes. A qPCR based on a fragment of the 16S rRNA gene was used to ensure the amplification of Listeria spp. genomic DNA. The standard curves showed efficiency values ranging between 92.3% and 105.8% and, R2 values > 0.98. The specificity of the method was also confirmed by the comparison of the results with those obtained by a previously reported conventional multiplex PCR. In addition, none of the strains which were not ascribed to L. monocytogenes amplified any of the target genes related to the four major serotypes of this pathogenic species. The qPCR, therefore, provides a sensitive, specific and rapid tool for identifying the L. monocytogenes serotypes 1/2a, 1/2b, 1/2c and 4b. This method could be very useful for identifying sources of L. monocytogenes contamination in the meat industry or for epidemiological monitoring of persistent strains throughout the processing of RTE meat products.

Molecular detection of enterotoxigenic Staphylococcus aureus in ready to eat beef products

Ready to eat (RTE) meat products are considered a rapid way to animal protein intake which may be preferred by consumers due to its palatability and quality; unfortunately, cooked meat products may be loaded by many foodborne pathogens especially Staphylococcus aureus (S. aureus) due to post cooking cross-contamination through mishandling andor getting in touch with raw materials; so, this study aimed to investigate the incidence of S. aureus in some RTE meat products followed by molecular detection of enterotoxigenic S. aureus isolates and its enterotoxin genes in 120 RTE meat products represented by luncheon, burger, shawerma and kofta (30 of each) which were collected from different restaurants and street vendors in Benha city, Qalubiya governorate, Egypt. Results revealed that kofta samples were the most contaminated samples with mean values 3.42x103, and 5.2x10 CFUg for total staphylococci and S. aureus counts, respectively; followed by burger, shawerma and luncheon samples. Multiplex PCR detection of S. aureus enterotoxins (SE) genes revealed detection of different isolates carrying staphylococcal enterotoxin type A, type B, mixed strain carrying both staphylococcal enterotoxins type A and type D was detected. So, RTE meat products of low hygienic measures may be risky to consumer’s health.