Ground Beef Samples Research Articles

The antimicrobial effect of fresh garlic and garlic oil supplemented with ground beef

Objective: The study was designed to investigate the antibacterial effect of fresh garlic and garlic oil against the aerobic bacteria in beef meatballs during their cold storage at 4°C. Design: Observational study Procedures: Three concentrations of fresh garlic (FG) (2%, 3%, and 5%) and garlic oil (GO) (250 mg/kg, 360 mg/kg, and 600 mg/g) were added to ground beef samples then treated meat and untreated (control) were kept in refrigeration at 4 °C for 15 days and their aerobic bacteria were determined. Results: The addition of garlic to ground beef significantly reduced (more than 3 log10 CFU/g) their aerobic bacteria during their refrigerated storage, in comparison with untreated meat. Furthermore, FG achieved a maximal reduction than GO, however, FG 5% and GO 600 mg/kg showed the most potent antibacterial effect. The sensory evaluation of treated meat revealed that FG 5% and GO 600 mg/kg had a significant strongest garlic flavor and the least acceptable score than other meat investigated. Conclusion and clinical relevance: The results indicated that garlic added to ground beef tested exhibited obvious effect against aerobic bacteria and can be used as a useful preservative in meat products.

Virulence genotyping and antimicrobial resistance profiles of Yersinia enterocolitica isolated from meat and meat products in Egypt.

Pathogenic Yersinia enterocolitica (Y. enterocolitica) is one of the food-borne entero-pathogen responsible for yersiniosis in humans. The purpose of this research was to survey the prevalence, virulence-associated genes, and antimicrobial resistance of Y. enterocolitica isolated from meat and meat product samples in Egypt. Forty-one (5.9%) out of 700- samples of chicken meat, beef, ground beef, and sausage were positive Y. enterocolitica with a high prevalence in chicken meat (12%). Five virulence genes (ail, inv, ystA, ystB, and yadA) were characterized among 41 Y. enterocolitica isolates with variable frequencies. Among the strains tested, the ystB gene was detected with a high percentage (78.1%), followed by inv gene (70.7%), ail gene (14.6%), ystA gene (12.2%), and yadA gene (2.4%). A high resistance rate was estimated to amoxicillin-clavulanic acid (100%), followed by cefazolin (95%), ampicillin (65.9%), and doxycycline (51.2%), whilst a high sensitivity rate was observed to gentamicin and ciprofloxacin (97.6% each). Interestingly, the multidrug resistance was specified in the 70.7% of strains and showing 13 resistance patterns. Based on nucleotide sequence analysis of the 16s rRNA gene, the phylogenetic tree showed the genetic relatedness amongst Y. enterocolitica isolates. These findings highlighted the emergence of virulent and multidrug-resistant pathogenic Y. entrocolitica in retailed meat and meat products in Egypt.

Antimicrobial Resistance in U.S. Retail Ground Beef with and without Label Claims Regarding Antibiotic Use

Antibiotics used during food animal production account for approximately 77% of U.S. antimicrobial consumption by mass. Ground beef products labeled as raised without antibiotics (RWA) are perceived to harbor lower levels of antimicrobial-resistant bacteria than conventional (CONV) products with no label claims regarding antimicrobial use. Retail ground beef samples were obtained from six U.S. cities. Samples with an RWA or U.S. Department of Agriculture Organic claim (n = 299) were assigned to the RWA production system. Samples lacking these claims (n = 300) were assigned to the CONV production system. Each sample was cultured for the detection of five antimicrobial-resistant bacteria. Genomic DNA was isolated from each sample, and a quantitative PCR assay was used to determine the abundance of 10 antimicrobial resistance (AMR) genes. Prevalence of tetracycline-resistant Escherichia coli (CONV, 46.3%; RWA, 34.4%; P < 0.01) and erythromycin-resistant Enterococcus (CONV, 48.0%; RWA, 37.5%; P = 0.01) was higher in CONV ground beef. Salmonella was detected in 1.2% of samples. The AMR gene blaCTX-M (CONV, 4.1 log-normalized abundance; RWA, 3.8 log-normalized abundance; P < 0.01) was more abundant in CONV ground beef. The AMR genes mecA (CONV, 4.4 log-normalized abundance; RWA, 4.9 log-normalized abundance; P = 0.05), tet(A) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), tet(B) (CONV, 3.9 log-normalized abundance; RWA, 4.5 log-normalized abundance; P < 0.01), and tet(M) (CONV, 5.4 log-normalized abundance; RWA, 5.8 log-normalized abundance; P < 0.01) were more abundant in RWA ground beef. Although these results suggest that antimicrobial use during U.S. cattle production does not increase human exposure to antimicrobial-resistant bacteria via ground beef, quantitative microbiological risk assessments are required for authoritative determination of the human health impacts of the use of antimicrobial agents during beef production.

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

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

Sodium sulfite research and microbiological analysis of ground beef and fresh sausage

In general, the meat contains nutrients of high biological value and susceptible to contamination by enteropathogens. One way of minimizing/eliminating this contamination is the use of food additives, in the case of meat, usually sodium sulphite. This technological resource is used to inhibit the growth of pathogenic bacteria such as Salmonella spp. and thermotolerant coliforms, mandatory parameters foreseen in sanitary legislation. Therefore, the objective of this article was to evaluate the presence of sodium sulfite and detection of Salmonella spp., total and thermotolerant coliforms in 23 samples of ground beef and 7 of fresh pork sausage, marketed in open markets and public markets of Grande Recife - PE. In a total of 30 samples analyzed, it was not detected in any presence of sodium sulphite. In the microbiological assays, also it was not detected the presence of Salmonella spp. and thermotolerant coliforms. The Total Coliforms was found in 20 meat samples (87%), at the maximum concentration of 35 MPN/g-1 and in all sausages (100%) at the concentration of 35 to 36 MPN/g-1. Although the Total Coliforms is not considered pathogenic, the presence of this indicates unsatisfactory sanitary conditions in the production, which may constitute biological risk for vulnerable groups.

Standardized Shiga-Toxin Encoding Genes Real-Time PCR Screening Methods Comparison and Development of an Internally Controlled Assay for Pan-stx2 Detection.

Various primer and probe sets have been developed and standardized, but certain sets may have low efficiency or miss some stx-subtypes. To compare the efficiency of the recommended stx screening primers and probe sets in four standardized methods and develop a new primers and probe system with an internal amplification control (IAC) for all known stx2 subtypes. The inclusivity and specificity of recommended screening primers and probe sets in four standardized methods were compared. A new pan-stx2 primer and probe set was adapted from the International Organization for Standardization (ISO) method for all known stx2 subtypes. The robustness of the new method was assessed in seven laboratories and also assessed in ground beef and bean sprout samples. None of the recommended screening primers and probe sets in the four standardized methods could efficiently amplify all the stx2 subtypes because of various mismatches in the primers or the probe sequences. A new primers and probe system adapted from the ISO method, through introducing degenerate bases in primers and probe sequences with an IAC, showed high amplification efficiency and specificity for all known stx2 subtypes in ground beef and bean sprouts samples. The specificity of the new method was assessed in seven laboratories and showed robust and consistent results. This study provided evidence for Shiga-toxin producing Escherichia coli (STEC) screening method development, and the newly developed primers and probes system should be considered in the revision of the standardized methods. None of the recommended screening primer and probe set in the four official methods could efficiently amplify all the stx2 subtypes. A new developed primer and probe set showed high amplification efficiency and specificity for all known stx2 subtypes in fresh ground beef and bean sprouts samples. The newly developed stx2 screening system showed robustness and consistency during interlaboratory study.

Recovery Rate of Cells of the Seven Regulated Serogroups of Shiga Toxin–Producing Escherichia coli from Raw Veal Cutlets, Ground Veal, and Ground Beef from Retail Stores in the Mid-Atlantic Region of the United States

A total of 482 veal cutlet, 555 ground veal, and 540 ground beef samples were purchased from retail establishments in the mid-Atlantic region of the United States over a noncontiguous 2-year period between 2014 and 2017. Samples (325 g each) were individually enriched and screened via real-time PCR for all seven regulated serogroups of Shiga toxin-producing Escherichia coli (STEC). Presumptive STEC-positive samples were subjected to serogroup-specific immunomagnetic separation and plated onto selective media. Up to five isolates typical for STEC from each sample were analyzed via multiplex PCR for both the virulence genes (i.e., eae, stx1 and/or stx2, and ehxA) and serogroup-specific gene(s) for the seven regulated STEC serogroups. The recovery rates of non-O157 STEC from veal cutlets (3.94%, 19 of 482 samples) and ground veal (7.03%, 39 of 555 samples) were significantly higher (P < 0.05) than that from ground beef (0.93%, 5 of 540 samples). In contrast, only a single isolate of STEC O157:H7 was recovered; this isolate originated from 1 (0.18%) of 555 samples of ground veal. Recovery rates for STEC were not associated with state, season, packaging type, or store type (P > 0.05) but were associated with brand and fat content (P < 0.05). Pulsed-field subtyping of the 270 viable and confirmed STEC isolates from the 64 total samples testing positive revealed 78 pulsotypes (50 to 80% similarity) belonging to 39 pulsogroups, with ≥90% similarity among pulsotypes within pulsogroups. Multiple isolates from 43 (67.7%) of 64 samples testing positive had an indistinguishable pulsotype. STEC serotypes O26 and O103 were the most prevalent serogroups in beef and veal, respectively. These findings support related findings from regulatory sampling studies over the past decade and confirm that recovery rates for the regulated STEC serogroups are higher for raw veal than for raw beef samples, as was observed in the present study of meat purchased at food retailers in the mid-Atlantic region of the United States.

Investigation of Aeromonas spp. in ground beef marketed in Afyonkarahisar

Ground beef as commonly consumed among animal products may be suitable for bacterial growth under unhygienic production and storage conditions. Aeromonas spp. can be widely found in the environment and it is associated with water. With contaminated water used in production, microorganisms pass into products and may pose a threat to public health. People are often infected by consuming contaminated water and meat products. Aeromonas spp. causes various disorders such as vomiting, diarrhoea and gastroenteritis. In addi-tion, children and older people are more susceptible to these bacteria. In this study, the presence of Aeromonas spp. was investigated by classical culture method in 100 ground beef samples which were sold in Afyonka-rahisar city centre. The suspected Aeromonas spp. were confirmed with VITEK® 2 Compact. The detected A. hydrophila strains were further investigated by PZR in terms ofaerA and hlyA genes. At the end of the analysis, A. hydrophila was identified in 3% of the ground beef samples. It was detected that all three bacteria have both the aerA and hlyA genes. In addition, only one of the identified strains was found to be resistant to amoxicillin and nalidixic acid. As a result, it is recommended to take necessary hygiene measures in all stages of red meat production according to farm to fork, to give attention to storage, heat treatment and inform consumers.

Incidence and contamination level of Clostridium perfringens in meat and meat products sold in Sakarya province of Turkey

Totally 101 meat and meat product samples obtained from local markets and restaurants were analyzed for incidence and contamination level of Clostridium perfringens. The typical colonies grown anaerobically on Tryptose Sulfite Cycloserine Agar supplemented with 4-Methyliumbelliferyl (MUP) were confirmed by biochemical tests. Forty-eight of the samples (47.5%) were contaminated with C. perfringens. The highest incidence of the pathogen was determined in uncooked meatball samples (72.2%) followed by ground beef samples (61.3%). The incidence of C. perfringens in chicken meat, cooked meat döner, cooked chicken döner and emulsified meat product samples were 33.3, 33.3, 28.6 and 16.7%, respectively. Thirteen out of 101 samples (12.9%) yielded typical colonies on TSC-MUP Agar, but could not be confirmed as C. perfringens. Average contamination levels in sample groups ranged from 8.3 to 1.5×102 cfu/g, with the highest ground beef and the lowest chicken meat.

Microbiological Quality of High-Demand Food from Three Major Cities in Ecuador

Bacterial foodborne diseases are among the most important public health issues worldwide, but in Ecuador, reports on the microbiological quality of food are scarce. In this cross-sectional study, 450 samples of high-demand Ecuadorian food, including bolon, encebollado, sauces, ceviche, fruit, fruit juice, fruit salad, cheese, raw chicken, and ground beef, were collected from popular street markets in the cities of Guayaquil, Quito, and Cuenca. Populations of total aerobic mesophilic bacteria, total coliforms, fecal coliforms, Escherichia coli, Salmonella enterica, and Listeria monocytogenes were examined on composited samples by plate count following the local regulations (Norma Tecnica Ecuatoriana, Instituto Ecuatoriano de Normalización) for each kind of food. The individual and interaction effects of the city and food type on the levels of each bacterial group were assessed by two-way analysis of variance. Selected colonies from each culture were identified using Biolog OmniLog ID and sequencing of the V3 to V4 region on the 16S rRNA gene. Average total aerobic mesophilic bacteria, total coliform, fecal coliform, and E. coli levels were 5.10 ± 0.12, 2.50 ± 0.16, 1.09 ± 0.12, and 0.83 ± 0.12 log CFU/g or mL, respectively, with significant variations among the cities. The prevalence of Salmonella in chicken and sauces and L. monocytogenes in cheese and fruit salad was greater than 20%. Opportunistic pathogens including Klebsiella pneumoniae, Staphylococcus sciuri, and Enterococcus spp. were frequently identified in the samples from all three cities. High prevalence of spoilage microorganisms such as Bacillus amyloliquefaciens and biocontrol bacteria such as Lactococcus lactis was also observed. This is the first report on the microbiological quality of food from Ecuador.

Identification of the gamma irradiation dose applied to ground beef that reduces Shiga toxin producing Escherichia coli but has no impact on consumer acceptance

The aims of the present study were: a) to estimate the minimal dose of gamma irradiation required to reduce 5 log CFU/g of native O157 and non-O157 Shiga toxin-producing Escherichia coli population in ground beef samples inoculated with high inoculum; b) to assess its effectiveness in samples with low inoculum and 3) to evaluate consumer acceptance. Based on the results, 1 kGy was estimated as the minimal dose of gamma irradiation required to reduce 5 log CFU/g of STEC in ground beef. However, when samples with low inoculum level were subjected to 1 kGy, 3.9% of the samples were positive for stx and eae genes after an enrichment step. Consumer acceptance analysis was carried out with samples subjected to 2.5 kGy and no significant differences were found between irradiated and control samples. Therefore, 2.5 kGy was identified as the gama irradiation dose that reduces STEC but has no impact on consumer acceptance of ground beef.

Application of Short Pre-enrichment, and Double Chemistry Real-Time PCR, Combining Fluorescent Probes and an Intercalating Dye, for Same-Day Detection and Confirmation of Salmonella spp. and Escherichia coli O157 in Ground Beef and Chicken Samples.

Molecular methods, particularly those based on real-time PCR (qPCR), have become a popular approach to detect pathogens in food samples. This technique may take advantage of hydrolysis fluorescent probes for increased specificity. Even though suitable, this approach loses the capacity of performing result confirmation by melt curve analysis. In the current study, we developed an alternative approach, combining fluorescent probes along with an intercalating dye (SYBR Green) in order to simultaneously detect, and confirm the result, of two foodborne pathogens (Salmonella spp. and Escherichia coli O157). This new approach named double chemistry qPCR was combined with a short pre-enrichment in order to obtain a multiplex “same-day” detection method for the selected pathogens. The evaluation of the novel method in spiked food samples (ground beef and chicken breast) obtained values of relative sensitivity, specificity, and accuracy higher than 95%, and Cohen’s kappa of 0.92, with a Limit of Detection95 below 5 cfu/25 g, demonstrating its reliability. In addition to this, the method was challenged by inoculating heat-stressed bacteria as well as dead ones. It was observed that it was also possible to detect stressed bacteria with an initial inoculation level below 10 cfu/25 g. Also, it was noticed that high initial concentration of either pathogen (higher than 104 cfu/25 g) was needed in order to generate false positive results due to the presence of dead bacteria, thus the method presents potential for its application in the specific detection of live microorganisms.

Determination of quaternary ammonium compounds in food products by the method of ultra-performance liquid chromatography/high resolution mass-spectrometry

The goal of the study is developing a methodology for determination of the residual amounts of quaternary ammonium compounds (QAC) in food products by UHPLC/high-resolution mass spectrometry after water-acetonitrile extraction of the determined components from the analyzed samples. The identification and determination of QAC was carried out on an «UltiMate 3000» ultra-high-performance liquid chromatograph (Thermo Scientific, USA) equipped with a «maXis 4G» high-resolution quadrupole-time-of-flight mass spectrometric detector and an ion spray «ionBooster» source (Bruker Daltonics, Germany). Samples of milk, cheese (upper cortical layer), dumplings, pork, chicken skin and ground beef were used as working samples. Optimal conditions are specified for chromatographic separation of the mixture of five QAC, two of them being a mixture of homologues with a linear structure (including isomeric forms). The identification of QAC is carried out by the retention time, exact mass of the ions, and coincidence of the mSigma isotopic distribution. The limits for QAC detection are 0.1 – 0.5 ng/ml, the determination limits are 1 ng/ml for aqueous standard solutions. The determinable content of QAC in food products ranges within 1 – 100 ng/g. The results of analysis revealed the residual amount of QAC present in all samples, which confirms data of numerous sources of information about active use of QAC-based disinfectants in the meat and dairy industry. The correctness of the obtained results is verified by introduction of the additives in food products at a level of 10 ng/g for each QAC. The relative standard deviation of the analysis results does not exceed 0.18. The duration of the analysis is 30 – 40 min.

Performance of Chromogenic Agar Media for Isolation of Shiga Toxin–Producing Escherichia coli from Ground Beef

The performance of three chromogenic agar media for detection of the "top seven" Shiga toxin-producing Escherichia coli (STEC) in beef was compared. Samples of retail ground beef were inoculated with STEC O26, O45, O103, O111, O121, O145, or O157 at geometric mean (±standard error of the mean) levels of 0, 48 (±1), 420 (±1), 4,100 (±1), or 45,000 (±1) CFU/10 g and enriched 1:10 (90 mL) in EC broth (40°C for 6 h). Following enrichment, aliquots of broth culture were treated by immunomagnetic separation with one of three pools of beads against the seven STEC serogroups: pool I, O26, O45, and O121; pool II, O103, O111, and O145; and pool III, O157. After immunomagnetic separation, 50 μL of washed bead suspensions in buffered peptone water were spiral plated onto modified Rainbow Agar O157 (mRBA), CHROMagar STEC (CS), or modified Possé differential medium (mPossé2) and incubated at 37°C for 18 h. Up to six isolated colonies were picked from each spiral plate based on expected colony phenotypes for STEC on the respective media, and isolate identity was confirmed with an 11-plex PCR assay targeting the O serogroups and virulence genes. Overall, mRBA had the highest sensitivity (99.2%), correctly detecting a significantly higher proportion of STEC serogroups than either CS (79.4%; P < 0.05) or mPossé2 (91.7%; P < 0.05). mRBA also had the highest negative predictive value (90.0%), correctly identifying a significantly higher proportion of true-negative samples compared with CS (25.7%; P < 0.05) and mPossé2 (46.2%; P < 0.05). However, mRBA also had the lowest analytical specificity of 83.2% (P < 0.05), yielding the lowest proportion of colonies tested that were STEC positive (3,548 of 4,263) compared with 97.7% (3,607 of 3,693) for mPossé2 and 98.0% (2,875 of 2,935) for CS. Reduced specificity results in more work and higher expense due to the increased number of colonies that must be tested. Further improvements in agar culture media for non-O157 STEC isolation are needed.

Translocation of Orally Inoculated Salmonella Following Mild Immunosuppression in Holstein Calves and the Presence of the Salmonella in Ground Beef Samples.

The objective of this study was to determine if immunosuppression through daily dexamethasone (DEX) infusion altered Salmonella translocation from the gastrointestinal tract. Weaned Holstein steers (n = 20; body weight [BW] = 102 ± 2.7 kg) received DEX (n = 10; 0.5 mg/kg BW) or saline (control [CON]; n = 10;) for 4 days (from day -1 to 2) before oral inoculation of naldixic acid-resistant Salmonella enterica Typhimurium (SAL; 3.4 × 106 colony-forming units [CFU]/animal) on day 0. Fecal swabs were obtained daily, and blood was collected daily for hematology. At harvest (day 5), ileum, cecal fluid, lymph nodes (ileocecal, mandibular, popliteal, and subscapular), and synovial (stifle, coxofemoral, and shoulder) samples were collected for isolation of the inoculated strain of SAL. White blood cell (WBC) and neutrophil concentrations were elevated (p < 0.01) in DEX calves following each administration event. Following inoculation, 100% of DEX calves shed the experimental strain of SAL for all 5 days, 90% of CON calves shed from day 1 to 3, and 100% of CON calves shed from day 4 to 5. Greater (p < 0.01) concentrations of SAL were quantified from the cecum of DEX calves (3.86 ± 0.37 log CFU/g) compared with CON calves (1.37 ± 0.37 log CFU/g). There was no difference in SAL concentrations between DEX and CON calves in ileal tissue (p = 0.07) or ileocecal (p = 0.57), mandibular (p = 0.12), popliteal (p = 0.99), or subscapular (p = 0.83) lymph nodes. Of the stifle samples collected, 3.3% were positive for SAL, highlighting a contamination opportunity during hindquarter breakdown. While more research is needed to elucidate the interactions of immunosuppression and pathogen migration patterns, these data confirm that orally inoculated SAL can translocate from the gastrointestinal tract and be harbored in atypical locations representing a food safety risk.

Northeastern U.S. Salmonella Strains from Retail Meat Are More Prevalent and More Resistant to Antimicrobials

Between 2002 and 2017, the National Antimicrobial Resistance Monitoring System (NARMS) recovered 5,803 Salmonella isolates from retail meat samples of chicken parts, ground turkey, pork chops, and ground beef collected in 21 states. NARMS tested these isolates for susceptibility to amoxicillin-clavulanic acid, ampicillin, azithromycin, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, gentamicin, nalidixic acid, streptomycin, tetracycline, trimethoprim-sulfamethoxazole (cotrimoxazole), sulfisoxazole, and ciprofloxacin. To evaluate possible geographic differences in the prevalence and distribution of antimicrobial-resistant Salmonella, we used a chi-square test of association. We used the U.S. Department of Agriculture Office of Investigation, Enforcement and Audit map for the regional subdivisions. A significant association was found between region, Salmonella prevalence, and Salmonella resistance to all tested antimicrobials except cotrimoxazole, streptomycin, ciprofloxacin, and azithromycin. The Northeast region was the most influential contributor to overall prevalence and resistance to most of the antimicrobials tested, and Salmonella Typhimurium was the serotype driving these associations. Although this work did not elucidate the reasons for differences in prevalence and antimicrobial resistance for Salmonella Typhimurium strains in the Northeast, lack of certain resistance mechanisms in Salmonella strains from other regions was ruled out by analysis of 484 sequences from the 485 isolates resistant to ampicillin, sulfonamides, and tetracycline.

The Effect of Different Packaging Systems on the Shelf Life of Refrigerated Ground Beef.

The aim of this study was to investigate the effects of different packaging systems on the shelf life of refrigerated ground beef. The ground beef samples were packaged as follows: AA (100% ambient air), 90O2:10CO2 (90% O2 and 10% CO2), 80O2:20CO2 (80% O2 and 20% CO2), 70O2:30CO2 (70% O2 and 30% CO2), 60O2:40CO2 (60% O2 and 40% CO2), 50O2:50CO2 (50% O2 and 50% CO2), 100O2 (100% O2), and VP (vacuum packaging). All treatments were analyzed daily for O2 and CO2 levels, pH, filtration time, total volatile basic nitrogen (TVB-N), aerobic mesophilic heterotrophic bacteria (AMHB), and aerobic psychrotrophic heterotrophic bacteria (APHB) over 20 days at 2 °C. All MAP systems had a decrease of O2 and an increase of CO2 levels during storage period (p < 0.05). Overall, the MAP systems were similarly able to decrease the pH and retard the increase of TVB-N and filtration time over the storage period (p > 0.05). Moreover, the MAP systems increased the lag phase and/or the generation time of both AMHB and APHB, extending the shelf life by 3 (90O2:10CO2), 4 (70O2:30CO2 and 100O2), and 5 days (80O2:20CO2, 60O2:40CO2, 50O2:50CO2, and VP). All MAP systems were equally effective in retarding physicochemical degradation; however, 80O2:20CO2, 60O2:40CO2, 50O2:50CO2, and VP were the most effective in impairing bacterial growth and extending the shelf life of ground beef stored under refrigeration.

Effect of the bovine TG5 gene polymorphism on milk- and meat-producing ability.

Aim:This study aimed to determine the effect of thyroglobulin (TG5) gene polymorphism on milk and meat productivity in the various cattle breeds currently bred in the Republic of Bashkortostan.Materials and Methods:The test was performed on dairy cattle of Black-and-White, Bestuzhev, and Simmental breeds, and meat cattle of Hereford and limousine breeds. The purpose of the test was to search for associations between the polymorphic alleles of the thyroglobulin (TG5) gene and economically useful traits.Results:All studied breeds showed a frequency predominance of the TG5C allele (from 0.56 to 0.71). A clear trend of an effect of the genotypes of the TG5 gene on milk-productivity indicators was revealed; cows with the TG5TT genotype have the highest milk yield and fat content in milk. The milk of cows of Bestuzhev and Simmental breeds that possessed this genotype was also characterized by higher protein content.Conclusion:We identified an effect of the polymorphism of the TG5 gene in the Hereford and limousine breeds on fat metabolism intensity indicators, such as fat output and fat content, in the longissimus muscle and in the general sample of ground beef.

Aspecto higiénico y sanitario de la carne molida comercializada en el municipio de Sinop – Mato Grosso

Ground beef is a highly perishable food and requires proper preservation and handling methods. It is marketed in butchers, supermarkets and grocery stores and has hygienic-sanitary recommendations recommended by legislation. Normative Instruction No. 83, of November 21, 2003, of the Ministry of Agriculture, Livestock and Supply, understands that ground meat is the meat product obtained from the grinding of carcass muscle masses, followed by immediate cooling or freezing. To perform the present work, 20 samples of refrigerated ground beef from commercial establishments in the municipality of Sinop-MT were used and submitted to microbiological analysis. Hygienic-sanitary conditions were verified through the presence of Salmonella spp. and Escherichia coli, mesophilic aerobic microorganism count and determination of the number of total and thermotolerant coliforms. The presence of Salmonella spp. was verified in 55% and E. coli in 60% of the samples. The count of mesophilic aerobic microorganisms ranged from 2.6x102 to 1.9x106 CFU/g. The values for determination of total coliforms ranged from 2,400 MPN/g, while for thermotolerants ranged from 3 to&gt; 2,400 MPN/g. These results are important, as 55% of the ground beef samples surveyed were in disagreement with the provisions of Resolution RDC No. 12 (Ministry of Health) for fresh meat. There is no standard in the legislation for total and thermotolerant coliforms, E. coli, and mesophilic aerobic microorganisms, but they are important because they are indicators of poor hygiene and sanitation, and some are capable of causing foodborne diseases.

Translocation of Orally Inoculated Salmonella Following Mild Immunosuppression in Dairy Calves and the Presence of the Salmonella in Ground Beef Samples

ObjectivesThe objective of this study was to determine if immunosuppression altered Salmonella (SAL) translocation from the GI tract subsequently contaminating the carcass during fabrication.Materials and MethodsWeaned Holstein steer calves (n = 20; BW = 102 ± 2.7 kg) received dexamethasone (DEX; n = 10; 0.5mg/kg BW), a synthetic glucocorticoid, or saline (CON; n = 10; 0.5mg/kg BW) for 4 d (from d –1 to d 2) via a jugular catheter prior to oral inoculation of nalidixic acid resistant Salmonella Typhimurium (3.4×106 CFU/animal) via milk replacer on d 0. Fecal swabs were obtained daily to ensure SAL infection. Blood was collected to assess hematological markers of immunosuppression. Upon harvest (d 5), the ileum, cecal content, lymph nodes (ileocecal, mandibular, popliteal and prescapular), and synovial (stifle, coxofemoral, and shoulder) swabs were collected for the isolation of the inoculated strain of SAL. The trim obtained during fabrication was then ground separating both fore and hind quarters of each carcass. Ground beef samples were collected using a random grab method then combined for a composite sample for each fore quarter and each hind quarter for every carcass. The sample were diluted with 225ml of PBSResultsFollowing inoculation, 100% of DEX calves shed the experimental strain of SAL for 5 d, 90% of CON calves shed from d 1 to 3, and 100% of CON calves shed from d 4 to 5. A treatment by tissue interaction (P &lt; 0.01) was observed for SAL in tissues collected at harvest. Greater (P &lt; 0.001) concentrations of SAL were quantified from the cecum of DEX calves (3.86 ± 0.37 log10 CFU) than CON (1.37 ± 0.37 log10 CFU); There was no difference in SAL concentrations between DEX and CON calves in ileal tissue (P = 0.07), nor ileocecal (P = 0.57), mandibular (P = 0.12), popliteal (P = 0.99), or prescapular (P = 0.83) lymph nodes. Salmonella was isolated from the stifle joint of one calf in the CON group; however, SAL was not isolated from any other joint fluids sampled. The prevalence of SAL in the ground beef samples was recovered in 7 of the 80 (8.75%) samples taken. This is important to note as it was 3.3% of swabs collected from the CON treatment and the opportunity exists for stifle joint fluid to come in contact with meat during hind quarter fabrication.ConclusionThe observed data suggests that the grab method for ground beef sampling may not be a correct quantification of overall presence of SAL in a ground beef sample. Therefore, further studies are needed to determine the effectiveness of pathogen sampling methods on ground beef.