Meat-borne Pathogens Research Articles

Green label marinades: A solution to salmonella and campylobacter in chicken products?

IntroductionThe presence of meat-borne pathogens entering the home remains a concern for consumers, despite advances made in improving antimicrobial interventions and systems within the processing line. Naturally antibacterial food ingredients including citrus juice and essential oils have been proven to inhibit the proliferation of microbial growth with varying success. AimsThis study aims to investigate the antimicrobial and sensory effects of mixtures of essential oils, fruit juices and herbs at established Minimum Inhibitory Concentrations (MICs) for their biopreservative effect on general microbiota of chicken and against chicken challenged with selected pathogenic/surrogate microorganisms. Materials and methodsThree marinade compositions were designed for use on chicken meat; lemon juice, thyme oil and black pepper (M1), lime juice, lemongrass oil and chilli paste (M2), and olive oil, oregano oil, basil oil and garlic paste (M3). These marinades were assessed for antibacterial effects against Salmonella enterica, Campylobacter jejuni and Listeria innocua on marinaded chicken drumsticks stored in aerobic conditions at 4 °C. Consumer tasting sessions were also conducted with a small focus group using selected final marinades. ResultsM1 and M2 were effective at significantly reducing initial pathogen carriage from 6 Log CFU/g to 2 Log CFU/g on refrigerated chicken meat as well as increasing the shelf-life of the product during cold-storage from 2 days to 7 days. However, consumer studies indicate that the flavours these marinades impart to treated products can be strong. ConclusionThese findings indicate that these designed marinades have shown excellent potential to improve food safety as well as shelf-life for the consumer, particularly in settings where food safety is often compromised such as barbecuing or in care settings. However, further recipe optimisation is required to make these marinades acceptable to consumers.

Review of major meat-borne zoonotic bacterial pathogens.

The importance of meat-borne pathogens to global disease transmission and food safety is significant for public health. These pathogens, which can cause a variety of diseases, include bacteria, viruses, fungi, and parasites. The consumption of pathogen-contaminated meat or meat products causes a variety of diseases, including gastrointestinal ailments. Humans are susceptible to several diseases caused by zoonotic bacterial pathogens transmitted through meat consumption, most of which damage the digestive system. These illnesses are widespread worldwide, with the majority of the burden borne by developing countries. Various production, processing, transportation, and food preparation stages can expose meat and meat products to bacterial infections and/or toxins. Worldwide, bacterial meat-borne diseases are caused by strains of Escherichia coli, Salmonella, Listeria monocytogenes, Shigella, Campylobacter, Brucella, Mycobacterium bovis, and toxins produced by Staphylococcus aureus, Clostridium species, and Bacillus cereus. Additionally, consuming contaminated meat or meat products with drug-resistant bacteria is a severe public health hazard. Controlling zoonotic bacterial pathogens demands intervention at the interface between humans, animals, and their environments. This review aimed to highlight the significance of meat-borne bacterial zoonotic pathogens while adhering to the One Health approach for creating efficient control measures.

Bacteriological quality and antimicrobial susceptibility profiles of isolates of ready-to-eat raw minced meat from hotels and restaurants in Arba Minch, Ethiopia.

In Ethiopia, the bacteriological quality of ready-to-eat raw meat is of a great public health concern as it can serve as a source of meat-borne pathogens and worsen the transmission of antimicrobial resistant bacteria, and hence this cross-sectional study, done on 257 meat samples (ie., 169 beef, 50 mutton and 38 chevon) from randomly selected hotels and restaurants (n = 52). Approximately 25 gm of meat samples were taken bi-weekly and subjected to quantitative and qualitative analyses; antimicrobial susceptibility tests were done as per the Kirby-Bauer disk diffusion method. It was found that 13.2 (n = 34), 17.5 (n = 45) and 21.8% (n = 56) samples exceeded the permissible limit for total viable and coliform and S. aureus counts, respectively. At the same time, 24.9% (n = 64) surpassed the bacteriological limit permissible for consumption. Overall, 36.6% (n = 94) of samples were extrapolated as unsatisfactory for consumption due to high bacterial load and or the presence of pathogens. Five different bacterial spp. such as E. coli 65% (n = 167), S. aureus 59% (n = 152), Salmonella spp. 28.4% (n = 73), Campylobacter spp. 14.4% (n = 37) and Shigella spp. 4.3% (n = 11) were isolated in varied proportions. Alarmingly, 60% (n = 264) of the isolates were multi-drug resistant and 51% of S. aureus were found to be MRSA.

Blue Light for Inactivation of Meatborne Pathogens and Maintaining the Freshness of Beef

Beef is rich in various nutrients but easily spoils due to bacterial contamination; thus, a bactericidal method is needed to inactivate meatborne pathogens while maintaining the freshness of beef. The present study was conducted to investigate for the first time the bactericidal effect of blue light (BL) at 415 nm against four meatborne pathogens (methicillin-resistant Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes) both in vitro and inoculated onto the surface of fresh beef. The populations of the four pathogens on the nonirradiated control beef did not change significantly (P > 0.05), whereas a dose-dependent inactivation effect was found for BL-treated beef both in vitro and in vivo. On the beef cuts, BL at 109.44 J/cm2 inactivated 90% of inoculated cells of the tested strains (P < 0.05), and this inactivation effect was sustained during 7 days of cold storage. Insignificant changes in lipid oxidation rate, water holding capacity, and cooking loss were found during storage between the control beef and the beef irradiated at 109.44 J/cm2 at the same time. BL had a minor and nonsignificant effect on surface color and free amino acid concentrations. The pH of the treated beef increased more slowly (P < 0.05) than did that of untreated beef. These results suggest that BL could be a novel bactericide and could help maintain the freshness of beef.

Biosensors for animal health and meat safety monitoring: farm-to-slaughterhouse continuum

The meat supply chain needs to be managed for sufficient levels of consumer protection. Healthy animals are an essential precondition for a safe food supply, since zoonotic diseases, including meatborne pathogens, are a major threat to public health. Information about the livestock’s general health, animal welfare and prevalence of major meatborne hazards such as Salmonella, Campylobacter, STEC and Listeria monocytogenes is of utmost importance for effective biosecurity control on farm. Early detection of these hazards in faecal samples, monitoring blood levels of metabolites relevant for animal welfare (hormones) and animal health (acute phase proteins) can provide high-level control in the animal farming industry. Multiplex biosensors for pathogens and metabolites in the farm-to-slaughterhouse continuum constitute a practical and cost-efficient tool for early detection of signs related to meat safety. Point-of-care multiplex biosensors are an advantage versus commonly used methods ELISA and RT-PCR, since they provide possibilities for early detection and do not require expensive equipment, trained personnel or significant time for sample transfer and analyses. Biosensors can improve meat inspection and meat safety controls, and can serve as a primary tool for monitoring food safety parameters and contribute to the modernization of veterinary inspection and risk-based meat safety assurance system.

Analysis of seroprevalence data on Hepatitis E virus and Toxoplasma gondii in wild ungulates for the assessment of human exposure to zoonotic meat-borne pathogens

Seroprevalence data for Toxoplasma gondii and Hepatitis E virus (HEV) in wild boar (Sus scrofa), roe deer (Capreolus capreolus), red deer (Cervus elaphus), mouflon (Ovis aries/musimon) and chamois (Rupicapra rupicapra) hunted/culled in northern Italy were used to fit seroprevalence distributions describing the exposure and co-exposure of the species to the two pathogens. The higher proportion of T. gondii and HEV seropositive animals was observed in wild boars with point estimate seroprevalence of 49% (N = 331) and 15% (N = 326) respectively. Data allowed comparisons by area (pre-Alpine Vs Alpine environment) for roe deer, red deer and mouflons. Contrasts between the distributions describing the uncertainty in seroprevalence suggest roe deer, red deer and mouflons have higher probability of being seropositive to T. gondii in pre-Alps. When considering HEV, few seropositive animals were detected and contrasts were symmetrically centred to zero for roe deer and red deer; mouflons shown higher probability of being seropositive in Alpine environment. HEV seropositive animals also included chamois (P = 5.1%, N = 97) in the Alpine districts, confirming circulation of HEV in remote areas. Evidence of HEV and T. gondii co-exposure was limited except for wild boars where it was observed in 30 samples representing 60% of the overall HEV-positive samples. Seroprevalence data of single infection and co-infection are extremely useful to investigate circulation of zoonotic pathogens in wild animals and estimate the foodborne risk of human exposure, however, these type of data do not directly translate into the presence/absence of the pathogen in seropositive and seronegative animals. At benefit of future development of quantitative risk assessments aiming at estimating the risk of human infection/co-infection via consumption of game meat, we developed and made available an online application that allows estimating the probability of the pathogen(s) being present as a function of seroprevalence data.

Antibacterial Activity of Rosmarinus officinalis against Multidrug-Resistant Clinical Isolates and Meat-Borne Pathogens.

Background In developing countries, the prevalence of bacterial infections is quite rampant due to several factors such as the HIV/AIDS pandemic, lack of hygiene, overcrowding, and resistance to conventional antimicrobials. Hence the use of plant-based antimicrobial agents could provide a low-cost alternative therapy. Rosmarinus officinalis is reputed as a medicinal plant in Ethiopia; however, its antibacterial activity against many of the clinical isolates remains overlooked. Methods Tender foliage of R. officinalis was collected and extracted in ethanol (EtOH) and evaluated for their antimicrobial activity against ten multidrug-resistant (MDR) clinical isolates, human type culture pathogens, and meat-borne bacterial isolates by employing agar well diffusion assay. Results EtOH extract of R. officinalis efficiently subdued the growth of all tested MDR clinical isolates in varying degrees. Salmonella sp. and Staphylococcus aureus were found to be the most sensitive clinical isolates. Likewise, it efficiently repressed the growth of meat-borne pathogens, particularly, S. aureus and Salmonella sp. showing its potentiality to be used as a natural antibacterial agent in the meat processing industry. The mechanism of antibiosis of plant extract against meat-borne pathogens is inferred to be bactericidal. Chemical constituents of the crude plant extract were analysed by Gas Chromatography-Mass Spectroscopy (GC-MS), Fourier Transform Infrared (FT-IR), and UV-visible spectroscopy showing genkwanin (26%), camphor (13%), endo-borneol (13%), alpha-terpineol (12%), and hydroxyhydrocaffeic acid (13%) as the major compounds. Conclusion Overall results of the present study conclude that R. officinalis could be an excellent source of antimicrobial agents for the management of drug-resistant bacteria as well as meat-borne pathogens.

Meat borne parasitic zoonoses in India

Meat borne zoonotic parasites prevalent in India include Taenia solium, Toxoplasma gondii and Sarcocystis suihominis. In addition, parasites such as Taenia saginata, Sarcocystis hominis, and Trichinella spiralis have also been reported. Primary routes of transmission of these parasites in the food animals involve consumption of food/water contaminated by eggs/cyst of the parasites. People become infected with meat borne zoonotic parasites after consuming raw or undercooked pork, mutton, chevon, game, and beef. Meat borne zoonoses are usually associated with poor hygiene and sanitary measures, improper cooking practices, lack of meat inspection and dearth of awareness. There is a need to run educational campaigns to create large scale awareness in public about the good hygiene, sanitation, and culinary practices, which could help to reduce the risk of meat borne pathogens. National level surveillance and control programs are required to determine the status of meat borne zoonotic pathogens. One health approach is the most viable solution to control meat-borne zoonotic parasites; the team members for One Health programs should include all the key stake holders for example, veterinarians, medical doctors, epidemiologists, farmers, consumers and policy makers. This review presents comprehensive information on the meat borne zoonotic parasites in India.

Phenotypic characterization of some foodpoisoning bacteria isolated from meat and meat products in Kaliobia, Egypt

The present study was performed on 250 random samples of fresh meat and meat products viz: Beef burger, kofta; minced meat and sausage (50 for each), were collected from different shops (25gm from each sample) at Kaliobia Governorate, Egypt, for detection the prevalence of some toxigenic food-borne bacteria , beside the phenotypic characterization and detection of some virulence genes . Bacteriological examination of the collected samples resulted in, isolation of 90 (36.0%) isolates of S. aureus isolates (41/16.4%); E. coli (25 /10.0%); B. cereus (21/8.4%) and Salmonella (3/1.2%) were recovered from 250 samples. ,Seven serogroups (O55:H7; O111:H4; O125:H18; O126:H7; O128:H27; O142:H2and O158:H2) were detected in 25 isolated E. coli strains. The antibiotic sensitivity tests for the isolated strains show multiple antibiotic resistances (ampicillin; methicillin; oxytetracycline; amoxicillin; streptomycin; erythromycin; doxycycline and cefotaxime). Therefore, E. coli; S. aureus and B. cereus strains especially antibiotic resistances ones are meat-borne pathogens of public health important.

Molecular studies on antibiotic resistant Bacillus cereus isolated from meat products and human in Kaliobia, Egypt

The current study was conducted on 210 random samples of meat products (beef burger, kofta, luncheon, minced meat, sausage) and diarrheic human stool of patients suffering from vomiting and diarrhoea (35 for each). The meat products were collected from different shops and hospitals at Kaliobia Governorate, Egypt, for detection of B. cereus strains, and their phenotypic characterization as well as antibiotic resistant genes. Bacteriological examination of the collected samples indicated the identification of 51 (24.3%) isolates of B. cereus from 210 samples as 11/31.4% from kofta 13/37.1% from minced meat; 9/25.7% from sausage; 7/20.0% from beef burger; 6 /17.1% from luncheon samples; and 5/14.3% from human stool specimens. Most of 51 isolated B. cereus strains had the ability for biofilm production. The antibiotic sensitivity profiles revealed that, the isolated B. cereus were highly resistant for Penicillin-G followed by methicillin; ampicillin; oxytetracycline; sulfa-trimethoprim and cefotaxime. Meanwhile, they were highly sensitive to to gentamycin and norfloxacin followed by ciprofloxacin; meropenem and florphenicol. Further, PCR declared that bla; tetA and erm genes were amplified in 9; 7; 6 out of 10 studied B. cereus isolates giving products of 680 bp.; 502 bp. and 645 bp. respectively. Therefore, one can conclude that; B. cereus especially antibiotic resistances ones are meat-borne pathogens of public health importance and they may be the causative agents in patients suffering from vomiting and diarrhoea.

Assessment of hygienic and nutritive quality of retailed minced meat in Egypt

The study was conducted on ninety fresh, chilled and frozen minced meat to determine their bacterial and nutritional quality and to be screened for meat-borne pathogens in the Menofiya governorate. Statistically, the findings of Aerobic mesophilic, coliform, Staphylococci, and Staphylococcus aureus counts were not significantly different (P >0.05) between the three meat types. Compared to the Egyptian organization standards (EOS), 82.2 % of minced meat had unacceptable Aerobic mesophilic counts, while 79% showed higher levels of S. aureus. In addition, the highest loads of Psychrotrophic counts (5.62 log cfu / g), Coliform counts (3.98 log cfu/g) and Mold and Yeast counts (4.99 log cfu /g) were found, correspondingly, in frozen, chilled and fresh minced meat. The overall incidence of Salmonella sp. out of the three meat types, was 27.8 %. Salmonellae was also isolated from fresh (33.3%), chilled (26.7%) and frozen (23.3%) minced meat. Salmonella Enteritidis and Salmonella Typhimurium were the major isolated strains. Regarding protein content, 73.3%, 80% and 66.7% of fresh, chilled and frozen minced meat were approved comparable to EOS, while all samples were accepted for fat content. In conclusion, the results of the current study indicate that the three minced meat types sold in the Menofiya governorate were not adequately hygienic. The Egyptian food hygiene authorities shall therefore consider the implementation of a pathogen-specific control system, beginning with primary production units, and strictly track compliance with hygiene measures during the preparation, processing and exhibiting of raw meat to obtain safe food.

Microbial contamination of moose (Alces alces) and white-tailed deer (Odocoileus virginianus) carcasses harvested by hunters

Hunting is currently a very popular activity, and interest in game meat is increasing. However, only limited research is available on the bacterial quality and safety of moose (Alces alces) and white-tailed deer (Odocoileus virginianus) harvested by hunters. Poor hunting hygiene can spread bacteria onto the carcasses, and inadequate chilling of the carcasses may increase the bacterial load on the carcass surface. We studied the bacterial contamination level on carcasses of 100 moose and 100 white-tailed deer shot in southern Finland. Hunters eviscerated carcasses in the field and skinned them in small slaughter facilities. During the sampling, same person visited 25 facilities located in 12 municipalities of four provinces. Moose carcasses had mean mesophilic aerobic bacteria (MAB), Enterobacteriaceae (EB) and Escherichia coli (EC) values of 4.2, 2.6 and 1.2 log10 cfu/cm2, respectively, while deer carcass values were 4.5, 1.5 and 0.7 log10 cfu/cm2, respectively. Moose carcasses were significantly more contaminated with EB and EC than deer carcasses. High bacterial counts (MAB>5.0 log10 cfu/cm2 and EB > 2.5 log10 cfu/cm2) on the carcasses were associated with the smallest facilities having only one room. The outdoor temperature and days between hunting and sampling affected the bacterial counts. High EB counts on the carcasses indicated a gut hit. Male gender was significantly more contaminated by EC and meat-borne pathogenic bacteria: Campylobacter spp., Salmonella spp., enteropathogenic Yersinia spp., stx-harbouring EC (STEC) and Listeria monocytogenes. STEC (28/200) and L. monocytogenes (20/200) were the most commonly detected bacteria by PCR. L. monocytogenes isolates of different sequence types (ST7, 18, 29, 37, 249, 412, 451 and 611) belonged to serotypes 1/2a (seven isolates) and 4b (three isolates). The virulence gene ail was detected in four Yersinia enterocolitica biotype 1A isolates and one Yersinia kristensenii isolate. The bacterial counts on the moose and deer carcasses varied highly, and more attention should be paid to hunting hygiene and training of hunters. Game meat may be a source of meat-borne pathogens, and close attention should therefore be paid when handling and preparing game.

Pasture is a risk factor for Toxoplasma gondii infection in fattening pigs

As consumer awareness of animal welfare increases throughout Europe, housing of pigs in more animal-friendly systems is becoming more common. There is concern that these free-range and organic management systems increase the prevalence of zoonotic meat-borne pathogens, such as Toxoplasma gondii. In this study we compared the seroprevalence of T. gondii between commercial fattening pigs raised on conventional and on organic farms in Sweden. Furthermore, potential associations between presence of T. gondii antibodies and type of production, access to pasture, and geographical region were analysed. A significant difference in T. gondii seroprevalence was found between conventional (1%) and organic pigs (8%). The higher odds of seropositivity in organic production was attributed to pasture access specifically (OR=1.8 for a one-month increase in length of pasture exposure). This study shows that the prevalence of T. gondii in Swedish conventional pigs is low. However, as pigs with access to pasture are at higher risk of infection and because the demand for animal-friendly production systems is increasing, there is an obvious need to practically manage the higher T. gondii presence in products from pigs raised in organic systems with outdoor access.

Bacteriological safety issues in red meat and ready-to-eat meat products, as well as control measures

The importance of Eschericha coli O157, Listeria monocytogenes and Salmonella typhimurium DT104 as meat-borne pathogens is well established. Pathogenic bacteria such as Aeromonas spp., Arcobacter spp., psychrotrophic Bacillus cereus, Campylobacter spp., Clostridium botulinum and non-invasive Listeria monocytogenes can be regarded as rookies, but not yet firmly associated with today's production of red meat and meat products. The development of PCR and other DNA-based techniques will shed new light on so called emerging pathogens. Important safety issues in meat production, such as insufficient cleaning and disinfection (including the stable/lairage, processing environment), carcass decontamination and chilling, and cross contamination are discussed. Furthermore, probability modelling of survival and growth is identified as an important way to achieve a better understanding of how to deal with the complexity of further processing, including heat treatment and storage.

Integrating microbial decontamination with organic acids in HACCP programmes for muscle foods: prospects and controversies

A considerable literature reports the antibacterial efficacy of dilute solutions of organic acids (lactic, acetic). With carcasses an overall reduction in surface contaminants of 1.5 log cycles can be expected. Carcass decontamination may not improve the safety of the resultant meat, but laboratory trials confirm that acid decontamination of subprimal and retail cuts is more efficacious. An advantage over many other intervention strategies is that residual antimicrobial activity is demonstrable over extended periods of storage. These studies have also shown that some meatborne pathogens are particularly sensitive to organic acids (i.e., Yersinia enterocolitica) while others are resistant (i.e., E. coli 0157:H7). Dilute solutions of organic acids (1 to 3%) are generally without effect on the desirable sensory properties of meat when used as a carcass decontaminant. However, dependent on treatment conditions, lactic and acetic acid can produce adverse sensory changes when applied directly to meat cuts, with irreversible changes in appearance being a frequent occurrence. It is speculated that organic acid decontamination will be implemented in American abattoirs in an effort to meet specified performance standards for pathogen reduction as part of an overall HACCP program. In contrast, the EU advocates that strictly controlled processing hygiene is sufficient to ensure the safety of the product. Additional research is necessary to establish a set of treatment conditions that may permit a practicable reduction in bacterial contamination throughout the processing chain with a measurable effect on safety and storage life, without imposing any change in sensory properties. It will also be necessary to develop standard, objective measures to assess HACCP and the efficacy of decontamination procedures. Without such commercial studies controversy on the practicality of acid decontamination will persist.

The immediate bactericidal effect of lactic acid on meat-borne pathogens

The kinetics of the bactericidal effect of lactic acid decontamination (LAD) on meat-borne pathogens (Salmonella spp., Campylobacter jejuni and Listeria monocytogenes) was studied in an in-vitro model. The bactericidal effect was greatest on organisms in the lactic acid film that replaced the natural fluid on the meat surface during LAD. A stepwise increase in pH from 2.6 to 3.5 and 4.0 progressively reduced the bactericidal effect of decontamination. For treatment with 2% lactic acid for 30-90 s at 21 degrees C, the immediate death of Salmonella spp. decreased from about 0.5-2 log10 cfu at pH 2.6 to an insignificant level at pH 4.0. The immediate death for Camp. jejuni decreased from 2.6 to > 5.3 at pH 2.6 to 0.3-1.0 at pH 4.0. The decrease in bactericidal effect with increasing pH could, however, be countered by an increase in the temperature from 21 degrees C to 37 degrees C. It is suggested that 2% LAD at 37 degrees C for 30-90 s is suitable for elimination of salmonellas on meat but not for L. monocytogenes. Decontamination with 1% lactic acid at pH 3.0 and 21 degrees C for at least 30 s was effective for Camp. jejuni. Mesophilic Enterobacteriaceae were reliable indicators of the LAD-induced bactericidal effect on Salmonella spp. and Camp. jejuni.

Factors affecting the susceptibility of meatborne pathogens and spoilage bacteria to organic acids

The bactericidal effects of lactic and acetic acids were assessed on artificially inoculated lean beef. The test bacteria included cold tolerant pathogens ( Listeria monocytogenes, Yersinia enterocolitica), mesophilic pathogens ( Salmonella typhimurium, Escherichia coli, Campylobacter jejuni and Staphylococcus aureus) and spoilage bacteria ( Pseudomonas fragi and Brochothrix thermosphacta). Acid temperature (20°C, 55°C), acid concentration (1%, 3%) and initial numbers of contaminating bacteria (log CFU/cm 2 of 3–6) were the variables studied. The bactericidal efficacy of organic acids was influenced by two- and three-way interactive effects that were often distinct for each organism. The magnitude of the reductions in bacterial numbers on acid-treated beef was similar with lactic and acetic acids. Bacterial numbers were maximally reduced with 3% acid at 55°C. The variations in the reductions in the numbers of bacteria on acid-treated beef were significantly affected by initial levels of bacterial contamination, but this effect followed no consistent pattern and varied with bacterial species. Of the pathogens tested, S. aureus was the most susceptible to acid (1·4 log cycle reduction) and S. typhimurium the least susceptible (0·4 log cycle reduction). The spoilage bacteria P. fragi (2·3 log cycle reduction) and B. thermosphacta (3·5 log cycle reduction) were more sensitive to the lethal effects of acid treatment than the pathogens.