Contamination Of Meat Products Research Articles

Polymerase Chain Reaction (PCR): An Alternative Rapid Method for Detection of Some Microbial Contamination of Meat Products

The use of advanced molecular techniques such as PCR has been introduced as a new fast and reliable method for detection of microbial contamination of food stuff. In this study, a total 160 samples of meat products (40 luncheon, 40 beef burger, 40 minced meat, and 40 fresh sausage) were examined for the presence of E. coli and pathogenic S. aureus using traditional methods of isolation and identification and PCR. The data obtained from this study showed that E. coli was isolated from 9 (22.5%), 13 (32.5%), 19 (47.5%), and 24 (60%) by traditional method comparing with 8 (20%), 13 (32.5%), 17 (42.5%), 23 (57.5%) out of 40 samples of luncheon, beef burger, minced meat, and fresh sausage samples respectively. While, S. aureus was isolated from 17 (42.5%), 11 (27.5%), 28 (70%), and 18 (45%) using traditional methods of isolation in comparison with 13 (32.5%), 8 (20%) 23 (57.5%), and 14 (35%) using PCR method out of 40 samples of luncheon, beef burger, minced meat, and fresh sausage samples correspondingly, with a sensitivity rate ranged from 87 to 96% in case of E. coli and 72 to 82% in case of S. aureus. Collectively, the data presented have revealed that, PCR is considered a fast, reliable and sensitive tool for detection of microbial contamination of food stuff.

Incidence of Listeria monocytogenes in Meat Product Samples by Real-Time PCR

The aim of this study was to trace a contamination of meat products with Listeria monocytogenes. Step One real time Polymerase Chain Reaction (PCR) was used. We used the PrepSEQ Rapid Spin Sample Preparation Kit for isolation of DNA and MicroSEQ® Listeria monocytogenes Detection Kit for the real-time PCR performance. We found out the strains of Listeria monocytogenes in hundred samples of meat products with no incubation. There was Internal Positive Control (IPC) in 40 samples. Our results showed that the real time PCR assay tested in this study might detect Listeria monocytogenes in meat product samples with no incubation sensitively.

Determination of levels of lead and cadmium contamination in meat products sold in northern lebanese markets

The levels of lead and cadmium have been determined in canned and processed meat products sold in North Lebanon. Such products are normally available all year round in the markets. Never before have these meat products been assessed for their levels of toxic metals nor have they been given the deserved attention regarding their impact on human health. Using closed-vessel microwave acid-assisted digestion and graphite furnace atomic absorption spectroscopy, the levels of lead (Pb) and cadmium (Cd) were determined in 75 brands of canned and 33 brands of processed (cold cuts) meat sold in the northern part of the country. The data provided extremely important information to whether or not Lebanese individuals are exposed to high levels of such toxic metals where specifi cally children were found to be more vulnerable to such exposures. In canned meat, the data showed that the levels of Pb ranged from 0.00020 to 0.8161 µg/g with a mean of 0.02696 µg/g, while 29 brands were below the detectable limit. As for Cd, the data revealed levels ranging from 0.00019 to 0.1382 µg/g with a mean of 0.01557 µg/g, while seven brands were below the detectable limit. In processed meat samples, Pb concentrations ranged from 0.00025 to 0.06135 µg/g with a mean of 0.0174 µg/g of which three brands showed nondetectable levels. Concentrations of cadmium ranged from 0.0000245 to 0.0071 µg/g where the mean concentration was found to be 0.002386 µg/g. Two major parameters, amount consumed and body weight, were found to play an important role in determining whether the provisional Tolerable Weekly Intake levels (PTWIs) of Pb and Cd were exceeded or not. Specifi cally for canned meats, certain samples have shown that the PTWI has been markedly exceeded in children for both metals.

A 3-year hygiene and safety monitoring of a meat processing plant which uses raw materials of global origin

A systematic approach in monitoring the hygiene of a meat processing plant using classical microbiological analyses combined with molecular characterization tools may assist in the safety of the final products. This study aimed: (i) to evaluate the total hygiene level and, (ii) to monitor and characterize the occurrence and spread of Salmonella spp. and Listeria monocytogenes in the environment and the final products of a meat industry that processes meat of global origin. In total, 2541 samples from the processing environment, the raw materials, and the final products were collected from a Greek meat industry in the period 2011–2013. All samples were subjected to enumeration of total viable counts (TVC), Escherichia coli (EC) and total coliforms (TCC) and the detection of Salmonella spp., while 709 of these samples were also analyzed for the presence L. monocytogenes. Pathogen isolates were serotyped and further characterized for their antibiotic resistance and subtyped by PFGE. Raw materials were identified as the primary source of contamination, while improper handling might have also favored the proliferation of the initial microbial load. The occurrence of Salmonella spp. and L. monocytogenes reached 5.5% and 26.9%, respectively. Various (apparent) cross-contamination or persistence trends were deduced based on PFGE analysis results. Salmonella isolates showed wide variation in their innate antibiotic resistance, contrary to L. monocytogenes ones, which were found susceptible to all antibiotics except for cefotaxime. The results emphasize the biodiversity of foodborne pathogens in a meat industry and may be used by meat processors to understand the spread of pathogens in the processing environment, as well as to assist the Food Business Operator (FBO) in establishing effective criteria for selection of raw materials and in improving meat safety and quality. This approach can limit the increase of microbial contamination during the processing steps observed in our study as well as the cross contamination of meat products.

Mechanically tenderized meat


 Background: In 2012, mechanically tenderized meat raised public health concern when an E.Coli 0157:H7 outbreak was linked to the tenderization process. It was discovered that the machinery pushed the E.Coli from the surface of contaminated meat products such as steaks and roasts, into the interior, where it was able to survive the cooking process. Concerns were raised by Lorraine McIntyre and the BCCDC about this issue, and their desire to improve their knowledge base in order to adequately assess the risk. Methods: Data was gathered via a survey conducted electronically and by telephone. Questions were asked to determine the proportion of retail establishments that use their own tenderizing equipment. Questions also asked about other industry practices such as current sanitization and labeling practices. Results: The results of this study were that 24% of surveyed establishments mechanically tenderize their meat products. Of these establishments, 33% have a label that states the meat has been tenderized mechanically and 17% provide cooking instructions on this label. An association was found between mechanically tenderizing meat and establishment type, which suggests that grocery stores are more likely to mechanically tenderize than other establishments, such as restaurants. On the other hand, no association was found between operator experience and their level of knowledge regarding the risks of mechanical tenderization. Conclusions: Overall, this study has demonstrated the likelihood is high that consumers purchase and consume beef that has been mechanically tenderized at the retail level. The results from this study can be used to aid public health officials in quantifying the risk of mechanical tenderization at a retail level and aid in the development and implementation of new legislation such as mandatory labeling of all mechanically tenderized meat.

Humoral immune responses in chickens and turkeys after infection with Toxoplasma gondii by using recombinant antigens

Toxoplasma gondii is a parasite which can be transmitted to humans via the consumption of contaminated meat products derived from different animal species, e.g., poultry. In Europe, the consumption rate of poultry meat is high and may pose a risk for humans. However, little is known about the prevalence and immune response against T. gondii in these animals. Based on these circumstances, we experimentally infected 18 turkeys and 16 chickens with the parasite. Turkeys were infected either with tachyzoites on different routes or with various amounts of oocysts. In contrast, chickens were only infected with different doses of oocysts. The immunoglobulin (Ig) Y humoral immune responses of these animals were investigated in a lineblot assay against the recombinant T. gondii antigens rGRA1, rGRA6, rGRA9, rSAG1, and rSUB1. By using the recombinant antigens rGRA6, rGRA9, and rSUB1 in the lineblot assay, we found a correlation between the humoral immune response and the parasite stage in turkeys. Thereby, an infection with oocysts induced a stronger, permanent long-lasting antibody response compared to tachyzoite-infected animals. Only a minor relation between the oocyst infection dose and the manifestation of the immune response in chickens was found 7days post infection (dpi) by using rGRA1 and rGRA9. However, an inconstant detection of antigen-specific IgY antibodies in the lineblot assay seems not to be a sufficient method for the identification of a Toxoplasma infection in chickens. In contrast, the detection of anti-rGRA6, anti-rGRA9, and anti-rSUB1 IgY antibodies showed potential for the identification of an infection in turkeys.

Staphylococcus aureus resistente à meticilina (MRSA) em alimentos de origem animal: uma revisão sistemática

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of infections in humans and onset of this bacterium in hospitalized individuals has been well documented. However, a report on MRSA colonization and infection of individuals in the community, without prior contact with hospital environment, suggests the occurrence of other sources of contamination, such as the use of drugs in livestock, causing colonization of production animals with MRSA, and resulting in contamination of meat products. This study aimed at compiling and analyzing the scientific publications on the occurrence of MRSA in foods. A systematic review of the literature was performed in Lilacs, Medline and Pubmed databases, and the articles published from 2000 to 2013 were selected. A significant number of studies involving different samples was observed. Wide variations on the MRSA prevalence were found, and also on the methodologies used for the analyses. The MLST strain ST398 is commonly detected in pigs, and it was the most isolated bacterium from samples analyzed in different studies. ST8 and ST5 strains, belonging to human biovar, have also been frfrequently isolated, suggesting that food handlers have been a source for meat contamination with MRSA.

Assessment of the Contamination of Some Foodstuffs by Escherichia coli O157 in Benin, West Africa.

Escherichia coli O157 is a pathogenic bacterium causing haemorrhagic colitis. It represents a serious public health problem in Northern America and Europe, which can plague Africa. Most cases of mentioned poisoning were related to contaminated meat products and vegetables. The present work aimed to estimate the prevalence of E. coli O157 in meat and vegetables in Benin. For this purpose, 6 lots of faeces samples from pigs and 8 from cattle were collected at the farms on the outskirts of Cotonou. Similarly, 20 samples of carcasses, 20 samples of intestines and stomach, and 20 surfaces samples of slaughtering equipment were taken. Vegetables and environment materials in gardens have also been sampled for 84 samples. Bacteriological analyses revealed a percentage of contamination of 50% for pig faeces and 25% for cattle ones. All the meats from stalling parks have been contaminated by this bacterium. For vegetables, 14.6% of samples were contaminated by E. coli O157. The presence of this pathovar in animal breeding and slaughtering environment and in the gardens shows that Benin is not aware of the risks of foodborne illness associated with the consumption of contaminated products. Therefore, it urges including that germ in a systematic search during safety control of food products in Benin.

Survival of Methicillin-ResistantStaphylococcus aureusDuring Thermal Processing of Frankfurters, Summer Sausage, and Ham

Infections from antibiotic-resistant bacteria are a major concern for human health professionals around the world. Methicillin-resistant Staphylococcus aureus (MRSA) is just one of the resistant organisms of concern. MRSA prevalence has also been recently reported in retail meat products at rates higher than originally thought. Although the risk of contracting an infection from handling contaminated meat products is thought to be low, very little is known about this organism from a food safety perspective. The objective of this study was to determine the survival of MRSA during thermal processing of frankfurters, summer sausage, and boneless ham. Frankfurters, summer sausage, and boneless ham were manufactured using formulations and processing procedures developed at the Iowa State University meat laboratory. Thermal processing resulted in a significant log reduction (p<0.05) for boneless ham, summer sausage, and frankfurters when compared to uncooked, positive controls for each of the three processed meat products. All products were thermally processed to an internal temperature of 70°C and promptly cooled to 7.2°C. Boneless ham showed the highest log reduction (7.28 logs) from cooking, followed by summer sausage (6.75 logs) and frankfurters (5.53 logs). The results of this study indicate that thermal processing of ham, summer sausage, and frankfurters to 70°C is sufficient to reduce the risk of MRSA as a potential food safety hazard.

Prevalence ofEscherichia coliO157 in Midwestern United States cattle

Abstract. Cattle fecal material has been shown to be a major reservoir for the foodborne pathogen Escherichia coli O157. Contaminated fecal material that comes into contact with the hide can lead to contamination of the carcass at slaughter. Thus, it is essential to minimize the prevalence of E. coli O157 in cattle feces in order to minimize the number of contaminated meat products. The Midwestern United States has variable weather patterns and is home to a large percentage of cattle used in the beef industry. The objective of this study was to determine if a prevalence difference of E. coli O157 exists among different Midwestern cattle herds and to assess fecal shedding in the winter and spring. Five Midwestern herds entering a single feedlot in Nebraska were sampled in February and May. Fecal samples (n=50) from each herd were collected and processed by multiple culture-dependent methods. Results of this study indicated that there was no difference in prevalence rates by location but a prevalence rate d...

Quantification of viable Escherichia coli O157:H7 in meat products by duplex real-time PCR assays

Rapid and specific detection of viable Escherichia coli O157:H7 cells in ready-to-eat (RTE) meat products, by duplex quantitative PCR (qPCR) procedures with mRNA and SYBR Green and TaqMan methodologies were developed. Specific primers and probes were designed based on the serotype of E. coli O157:H7, fliCh7 and rfbE genes. No cross-reactivity with other microorganisms was observed. The detection limit of the assays was 101 or 102CFU/g for artificially contaminated meat products, and after a 4h enrichment period at 37°C, the detection limit decreased to about 1CFU/g. Time-to completion of the assay was approximately 8h. Thus, these qPCR methods offer a useful, rapid and efficient tool for screening viable E. coli O157:H7 in RTE meat products. This tool could also be proposed for monitoring these foodborne pathogens in HACCP programs.

Absence of E coli O157:H7 in sheep and cattle faeces in North Wales

Escherichia coli O157:H7 is a human pathogen associated with haemolytic uraemic syndrome and haemorrhagic colitis cases throughout the developed world (Garcia and others 2010). The faeces of ruminant animals, in...

Predictive model for the reduction of heat resistance of Listeria monocytogenes in ground beef by the combined effect of sodium chloride and apple polyphenols

We investigated the combined effect of three internal temperatures (57.5, 60, and 62.5°C) and different concentrations (0 to 3.0wt/wt.%) of sodium chloride (NaCl) and apple polyphenols (APP), individually and in combination, on the heat-resistance of a five-strain cocktail of Listeria monocytogenes in ground beef. A complete factorial design (3×4×4) was used to assess the effects and interactions of heating temperature, NaCl, and APP. All 48 combinations were tested twice, to yield 96 survival curves. Mathematical models were then used to quantitate the combined effect of these parameters on heat resistance of the pathogen. The theoretical analysis shows that compared with heat alone, the addition of NaCl enhanced and that of APP reduced the heat resistance of L. monocytogenes measured as D-values. By contrast, the protective effect of NaCl against thermal inactivation of the pathogen was reduced when both additives were present in combination, as evidenced by reduction of up to ~68% in D-values at 57.5°C; 65% at 60°C; and 25% at 62.5°C. The observed high antimicrobial activity of the combination of APP and low salt levels (e.g., 2.5% APP and 0.5% salt) suggests that commercial and home processors of meat could reduce the salt concentration by adding APP to the ground meat. The influence of the combined effect allows a reduction of the temperature of heat treatments as well as the salt content of the meat. Meat processors can use the predictive model to design processing times and temperatures that can protect against adverse effects of contaminated meat products. Additional benefits include reduced energy use in cooking, and the addition of antioxidative apple polyphenols may provide beneficial health affects to consumers.

In Romania, exposure to Toxoplasma gondii occurs twice as often in swine raised for familial consumption as in hunted wild boar, but occurs rarely, if ever, among fattening pigs raised in confinement

A wide range of swine husbandry practices prevail in Romania: pork for human consumption is derived from hunting wild boar, from household rearing of small numbers of backyard pigs, and from indoor, industrial production of swine raised in confinement indoors. Romania thus represents an instructive place for evaluating the influence of animal management on the exposure risk of the zoonotic parasite, Toxoplasma gondii. The fact that many Romanians eat uncooked or undercooked pork, especially when raised for household consumption, elevates the public health imperative to understand these risks. The aim of the study, therefore, was to evaluate the seroprevalence of T. gondii in pigs and wild boars from Romania. During 2008-2010, we collected 3,595 serum samples from pigs (fattening pigs, sows, backyard pigs) and 150 serum samples from wild boars. The sera were assayed by immunofluorescence antibody test (cutoff, 1:32) for antibodies against T. gondii. The overall seroprevalence of T. gondii infection was 23.1% (829/3,595) in pigs and 16% (24/150) in wild boars. The seroprevalence was significantly higher (p < 0.001) in backyard pigs (30.5%; 783/2,564) than in sows (12.4%; 46/371) or fattening pigs (none of the sera was positive). The management system (indoor pigs versus backyard pigs) represented the most important factor in the epidemiology of T. gondii infection. The proximity of backyard pigs to the definitive host of this parasite (cats), as well as their access to contaminated meat products, elevated their exposure risk well above that of pigs raised in confinement, and even above that of wild boars inhabiting sylvatic environments.

Importance of the producer on retail broiler meat product contamination with Campylobacter spp

Campylobacter spp. are a leading cause of human bacterial gastroenteritis worldwide, with poultry meat being considered the most important source of the infection. To obtain data on broiler meat contamination with Campylobacter spp. in Lithuania, the occurrence, counts and genotypes of these pathogens on raw broiler meat products from different producers were examined. Out of 312 broiler meat product samples examined, 46.8% were contaminated with Campylobacter spp. Campylobacter jejuni was identified in 51.4% and Campylobacter coli in 37.7% of positive samples. Campylobacter jejuni was more frequently found in the warm period (April-October) and C. coli in the cold period (November-March) of the year (P < 0.05). The overall mean count of Campylobacter spp. was 3.55 and 3.50 log10 colony-forming units (CFU) on wings and drumsticks respectively. The occurrence and counts of Campylobacter spp. varied significantly between producers examined (P < 0.05). Analysis of flaA-RFLP genotyping revealed C. jejuni genotypes common to all producers as well as producer-specific genotypes. Both the occurrence and counts of Campylobacter spp. on broiler meat products were producer-dependent, so this should be kept in mind when risk-based control measures at national level are applied.

Isolation and Characterization of Clostridium difficile Associated with Beef Cattle and Commercially Produced Ground Beef

The incidence of Clostridium difficile infection has recently increased in North American and European countries. This pathogen has been isolated from retail pork, turkey, and beef products and reported associated with human illness. This increase in infections has been attributed to the emergence of a toxigenic strain designated North America pulsed-field gel electrophoresis type 1 (NAP1). The NAP1 strain has been isolated from calves as well as ground meat products, leading to speculation of illness from consumption of contaminated meat products. However, information on C. difficile associated with beef cattle during processing and commercially produced ground beef is limited. To address this data gap, samples from various steps during beef production were collected. Samples from hides (n = 525), preevisceration carcasses (n = 475), postintervention carcasses (n = 471), and 956 commercial ground beef samples were collected from across the United States. The prevalence of C. difficile spores on hides was 3.2%. C. difficile spores were not detected on preevisceration and postintervention carcasses or in commercially produced ground beef. Phenotypic and genetic characterizations were carried out for all 18 isolates collected from hide samples. Twenty-two percent of the isolates were nontoxigenic strains, while 78% of the isolates were toxigenic. Toxinotyping and PCR ribotyping patterns revealed that 6 and 33% of the isolates were identified as NAP1 and NAP7 strains, respectively. This article evidences that the prevalence of C. difficile, specifically pathogenic strains, in the U.S. beef production chain is low.

Characterization of clostridial species and sulfite-reducing anaerobes isolated from foie gras with respect to microbial quality and safety

Anaerobic sulfite-reducing bacteria are generally considered as indicators of clostridial contamination in meat products. We reconsidered the relevance of this indicator for crude and pasteurized foie gras. A three-year study was conducted to recover anaerobic sulfite-reducing bacteria from foie gras manufactures. Under anaerobic culture at 37 °C, 98 isolates were obtained from crude or pasteurized foie gras, surfaces and pepper used in the recipe and further identified. Heat-treated products lead to the exclusive isolation of Clostridium strains, but other samples demonstrated a high diversity of non-spore forming bacterial species. The diversity in the Clostridium group was also high, with 14 different species represented from the 49 clostridial isolates, including Clostridium perfringens and psychrotolerant species. All the 12 C. perfringens isolates belonged to type A, but none carried the enterotoxin gene. In addition, none of them was able to grow in foie gras at 8 °C over a 130-days period. Other species were also tested for their ability to grow in these conditions: only three isolates, identified as Clostridium sordellii, Clostridium tertium and Clostridium algidicarnis/putrefaciens, grew at 8 °C, exhibiting 5 to 6 log of population increase in 70 days. Consequently, regarding the risk of product spoilage, we recommend anaerobes enumeration at 37 °C for pasteurized foie gras products, or after a thermal treatment aiming at spore selection, for crude foie gras.

Evaluation of the Concentration of Nonessential and Essential Elements in Chicken, Pork, and Beef Samples Produced in Brazil

Food safety is a global concern. Meat represents the most important protein source for humans. Thus, contamination of meat products by nonessential elements is a ready source of human exposure. In addition, knowledge of the concentration of essential elements is also relevant with respect to human nutrition. The aim of the present study was to determine the concentration of 17 elements in pork, beef, and chicken produced in Brazil. Meat samples were analyzed by inductively coupled plasma mass spectrometry. The estimated daily intake for nonessential elements including arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and antimony (Sb) through meat consumption is below the toxicological reference values. However, high levels were detected for the nonessential element cesium (Cs), mainly in beef samples, an observation that deserves future studies to identify the source of contamination and potential adverse consequences.

Interferon-γ Restricts Toxoplasma gondii Development in Murine Skeletal Muscle Cells via Nitric Oxide Production and Immunity-Related GTPases

The apicomplexan parasite Toxoplasma gondii is regularly transmitted to humans via the ingestion of contaminated meat products from chronically infected livestock. This route of transmission requires intracellular development and long-term survival of the parasite within muscle tissue. In this study, we determined the cell-autonomous immunity of mature primary embryonic or C2C12 skeletal muscle cells (SkMCs) to infection with T. gondii. Non-activated SkMCs and control fibroblasts sustained parasite replication; however, interferon (IFN)-γ significantly inhibited parasite growth in SkMCs but not in fibroblasts. Intracellular parasite replication was diminished by IFN-γ whereas host cell invasion was not affected. Tumor necrosis factor (TNF) did not further increase the IFN-γ-triggered host defense of SkMCs against Toxoplasma. Remarkably, IFN-γ alone or in combination with TNF decreased the high level of T. gondii bradyzoite formation being observed in non-activated SkMCs. Stimulation of SkMCs with IFN-γ strongly triggered expression of inducible nitric oxide synthase (iNOS) transcripts, and induced significantly higher levels of nitric oxide (NO) in SkMCs than in fibroblasts. Consequently, pharmacological inhibition of iNOS partially abrogated the IFN-γ-induced toxoplasmacidal activity of SkMCs. In addition, SkMCs strongly up-regulated immunity-regulated GTPases (IRGs) following stimulation with IFN-γ. IRGs accumulated on Toxoplasma-containing vacuoles in SkMCs in a parasite strain-dependent manner. Subsequent vacuole disruption and signs of degenerating parasites were regularly recognized in IFN-γ-treated SkMCs infected with type II parasites. Together, murine SkMCs exert potent toxoplasmacidal activity after stimulation with IFN-γ and have to be considered active participants in the local immune response against Toxoplasma in skeletal muscle.

The rapid detection of E. coli 0157 Antigen in meat products by using ELISA Test Kit

This study was conducted for rapid detection of contamination of meat products with E. coli 0157 by usage of ELISA test kit as one of the most rapid and newest test. The study showed the efficiency of ELISA test kit used in this study in detection of bacteria antigen in meat products samples of raw beef meat , kabab and beef burger which subjected to improper storage conditions or undercooked and hence when some peoples uptake some of these products they suffered from clinical intoxication signs like diarrhea ,vomiting and hyperthermia. The kit showed the presence of (9) samples positive among (90) samples ; (2) positive out of (30) kabab samples,(3) positive out of (30) beef burger and (4) positive out of (30) raw beef meat after 16 hrs of enrichment of all samples in EC Modified broth including Novobiocin supplement as inhibitor of other bacteria and then the liquid supernatants from all prepared samples got tested by ELISA kit used in this study and the data recovered in less than 1 hr.The study indicated the ability of using ELISA kit for detection of E. coli 0157 antigens in food stuffs and reduce the time for releasing the results in less than 24 hrs when compared with conventional culturing procedure which reuiqred more than 3 days and launch the food products for consumption with focusing on the main point here which is the protection of our consumer safety.