Occurrence of pathogens in raw and ready-to-eat meat and poultry products collected from the retail marketplace in Edmonton, Alberta, Canada

A total of 800 meat and poultry products were purchased from the retail marketplace in Edmonton, Alberta, Canada. The products consisted of raw ground beef, chicken legs, pork chops, and ready-to-eat fermented sausage, roast beef, processed turkey breast, chicken wieners, and beef wieners. The samples were analyzed to determine the prevalence of Shiga toxin-producing Escherichia coli, Salmonella, Campylobacter spp., and Listeria monocytogenes. Shiga toxin-producing E. coli 022: H8 was found in one raw ground beef sample. Salmonella and Campylobacter were found in 30 and 62% of raw chicken legs, respectively. L. monocytogenes was found in 52% of raw ground beef, 34% of raw chicken legs, 24% of raw pork chops, 4% of fermented sausages, 3% of processed turkey breast, 5% of beef wieners, and 3% of chicken wieners. The occurrence of pathogens in this study is similar to that in retail products in many other international locales.     

Quantification of beef,pork, chicken and turkey proportions in sausages: use of matrix-adapted standards and comparison of single versus multiplex PCR in an interlaboratory trial

Quantitative PCR methods for the determination of beef, pork, chicken and turkey proportions in sausage were tested in an interlaboratory trial. Twelve different laboratories analysed six meat products each made of different compositions of beef, pork, chicken and turkey. Two kinds of calibrators were used: sausages of known proportions of meat and DNA from muscle tissue. Results generated using calibration sausages were more accurate than those resulting from the use of muscle tissue DNA. Regardless of the method used (either multiplex or single PCR), when using calibration sausages, it was always possible to quantify the proportions of meats in the unknown samples (in the range of 0.5–80%) with high precision and accuracy.     

The effect of heat treatment on the cholesterol oxides,cholesterol, total lipid and fatty acid contents of processed meat products

The effects of heat treatment on the formation of cholesterol oxides and on alterations of fatty acid composition were investigated in processed meat products. Meatballs (beef), hamburger (beef and Chester), sausage (pork, chicken and Chester) and frankfurter (mixed meat, chicken and Chester) were analysed. There was no cholesterol oxide formation caused by heat treatment of the samples analysed. The fatty acid compositions, calculated as g/100 g sample, showed alterations only between the raw and grilled beef hamburger. Only the cholesterol levels were significantly changed when comparing the raw and grilled pork sausages and the raw and grilled Chester hamburger, the values being lower in the grilled samples. Also, the total lipid contents of grilled beef hamburgers were lower than the values.     

Detection of meat species using TaqMan real-time PCR assays

Species-specific real-time PCR (TaqMan) assays were developed for detection of beef, pork, lamb, chicken and turkey. Assays were developed around small (amplicons <150 base pairs) regions of the mitochondrial cytochrome b (cytb) gene. Speciation was achieved using species-specific primers. For detection purposes, two TaqMan probes were developed; the first was specific to the mammalian species (beef, lamb and pork), the second to the poultry species (chicken and turkey). Normal end-point TaqMan PCR conditions were applied; however, PCR was limited to 30 cycles. Applying the assays to DNA extracts from raw meat admixtures, it was possible to detect each species when spiked in any other species at a 0.5% level. The absolute level of detection, for each species, was not determined; however, experimentally determined limits for beef, lamb and turkey were below 0.1%.     

Species identification in food products using the bioMerieux FoodExpert-ID<Superscript>®</Superscript> system

Animal feeds and meat mixtures were analysed using the bioMerieux FoodExpert-ID^® system. The system utilises a reverse dot technique on a DNA microarray to allow the identification of over 30 species of fish, birds and mammals. DNA is amplified by PCR (polymerase chain reaction) then hybridised to the microarray chip. Using this technique, turkey and chicken were correctly identified in 100% of feed samples that contained these species above a level of 0.1%. Pig, lamb and cow could not be reliably detected below a level of 1% in feed samples. For meat mixtures, a level of 0.2% pork or chicken could be correctly identified when mixed with 50% beef or pork, respectively. When a baked or canned meat mixture was investigated, a level of 5% pork, beef or chicken could be correctly identified, following either process. The bioMerieux FoodExpert-ID^® system can therefore be used as a general screen to identify likely species present in a sample, the level of which can be confirmed using other methods.     

Identification of chicken,duck, pigeon and pig meat by species-specific markers of mitochondrial origin

In the present study, PCR based method for meat species identification of chicken, duck, pigeon and pig was achieved by developing species-specific markers. Using mitochondrial sequences species-specific primers were designed and the sizes of them were 256 bp, 292 bp, 401 bp and 835 bp for chicken, duck, pigeon and pig, respectively. The species-specific PCR products were sequenced to confirm the specificity of the product amplified. These markers were subsequently tested for cross amplification by checking them with beef, mutton, chevon, pork, rabbit, chicken, duck, turkey and pigeon meat. DNA markers developed in this study can help identify the species of fresh, cooked and autoclaved meat of chicken, duck and pigeon and fresh and cooked meat of pig. The process of identification is simple, economical and quick as compared to other methods such as RAPD, PCR-RFLP and sequencing method of species identification.     

Detection of chicken and turkey meat in meat mixtures by using real-time PCR assays

In this study, TaqMan-based real-time Polymerase Chain Reaction (PCR) techniques were developed for the detection of chicken and turkey meat in raw and heat-treated meat mixtures. Primers and TaqMan probe sets were designed to amplify 86 bp and 136 bp fragments for the chicken and turkey species, respectively, on the mitochondrial NADH dehydrogenase subunit 2 gene. In the results, it was possible to detect each species at the level of 0.1 pg template DNA with the TaqMan probe technique without any cross-reactivity with nontarget species (bovine, ovine, donkey, pork, and horse) while the detection level was 1 pg template DNA using conventional PCR. The TaqMan probe assays used in this study allowed the detection of as little as 0.001% level of both species in the experimental meat mixtures, prepared by mixing chicken and turkey meat with beef at different levels (0.001% to 10%). In conclusion, TaqMan probe assays developed in this research are promising tools in the specific identification and sensitive quantification of meat species even in the case of heat-treated meat products, and suitable for a rapid, automated, and routine analysis.     

Analysis of lard in meatball broth using Fourier transform infrared spectroscopy and chemometrics

Meatball is one of the favorite foods in Indonesia. For the economic reason (due to the price difference), the substitution of beef meat with pork can occur. In this study, FTIR spectroscopy in combination with chemometrics of partial least square (PLS) and principal component analysis (PCA) was used for analysis of pork fat (lard) in meatball broth. Lard in meatball broth was quantitatively determined at wavenumber region of 1018–1284 cm^− 1. The coefficient of determination (R²) and root mean square error of calibration (RMSEC) values obtained were 0.9975 and 1.34% (v/v), respectively. Furthermore, the classification of lard and beef fat in meatball broth as well as in commercial samples was performed at wavenumber region of 1200–1000 cm^− 1. The results showed that FTIR spectroscopy coupled with chemometrics can be used for quantitative analysis and classification of lard in meatball broth for Halal verification studies. The developed method is simple in operation, rapid and not involving extensive sample preparation.     

ACCEPTABILITY OF VARIOUS GROUND BEEF AND PORK PRODUCTS EXTENDED WITH MECHANICALLY SEPARATED BEEF

Six blends of ground beef and six blends of ground pork containing 0, 15, 30, 45, 60 or 75% mechanically separated beef (MSB) were prepared. Also five batches of fermented sausage and spiced luncheon loaf containing 0, 5, 10, 15 and 20% MSB were formulated. Level of MSB was not related to juiciness rating or mealiness scores of cooked beef/MSB or pork/MSB patties. The level of MSB significantly affected overall eating satisfaction ratings for each blend of MSB patties. MSB at levels of 15% or more had a negative effect on flavor acceptability of cooked ground beef or pork. Fermented sausage products could be extended with only 5% MSB without creating defects in visual appearance or sensory properties. However, the inclusion of 20% MSB yielded a spiced luncheon loaf which was higher in eating quality than an all-beef control. The beef/MSB patties, fermented sausage, and spiced luncheon loaves containing 15% MSB were acceptable for visual appearance. Based on this study, MSB produced from a press type machine, can be blended up to 15% with ground beef, ground pork and sausage products without significantly decreasing raw appearance, sensory properties or storage life. Since MSB is a red meat product available at a similar low cost as textured vegetable protein, the red meat industry would benefit from expanded use of this high protein extender.     

Optimization of emulsion characteristics of beef, chicken and turkey meat mixtures in model system using mixture design

Emulsion pH (pHe), emulsion capacity (EC), emulsion stability (ES), emulsion density (ED) and apparent yield stress of emulsion (raw emulsion, AYSe) and emulsion gel (cooked emulsion, AYSg) of beef, chicken and turkey meats and their mixtures were studied using a model system.

Turkey meat homogenate was found to have higher protein concentration than chicken or beef homogenates. The highest pHe, EC and ES values and the lowest ED and AYSe values were found in chicken meat. However, the highest AYSg value was found in chicken–turkey meat mixture. Generally, the increasing amount of chicken meat in mixtures increased EC and ES, and decreased ED and AYSe values. Also, chicken–turkey meat mixtures had lower ES values than the mixtures containing only chicken or only turkey meat. With beef, the addition of chicken and turkey meats improved emulsion characteristics significantly. Optimum levels of beef, chicken and turkey meats were found to be 0–23%, 9–30% and 53–91% respectively.     

Lead and cadmium in meat and meat products consumed by the population in Tenerife Island, Spain

The aim of this study was to determine the levels of lead and cadmium in chicken, pork, beef, lamb and turkey samples (both meat and meat products), collected in the island of Tenerife (Spain). Lead and cadmium were measured by graphite furnace atomic absorption spectrometry (GFAAS). Mean concentrations of lead and cadmium were 6.94 and 1.68 µg kg^-1 in chicken meat, 5.00 and 5.49 µg kg^-1 in pork meat, 1.91 and 1.90 µg kg^-1 in beef meat and 1.35 and 1.22 µg kg^-1 in lamb meat samples, respectively. Lead was below the detection limit in turkey samples and mean cadmium concentration was 5.49 µg kg^-1. Mean concentrations of lead and cadmium in chicken meat product samples were 3.16 and 4.15 µg kg^-1, 4.89 and 6.50 µg kg^-1 in pork meat product, 6.72 and 4.76 µg kg^-1 in beef meat product and 9.12 and 5.98 µg kg^-1 in turkey meat product samples, respectively. The percentage contribution of the two considered metals to provisional tolerable weekly intake (PTWI) was calculated for meat and meat products. Statistically significant differences were found for lead content in meats between the chicken and pork groups and the turkey and beef groups, whereas for cadmium concentrations in meats, significant differences were observed between the turkey and chicken, beef and lamb groups. In meat products, no clear differences were observed for lead and cadmium between the various groups.     

Application of a multiplex PCR for the simultaneous detection of Escherichia coli O157:H7, Salmonella and Shigella in raw and ready-to-eat meat products

Escherichia coli O157:H7, Salmonella and Shigella might contaminate similar types of meat products and cause deadly diseases in humans. Traditional microbiological analyses to detect these pathogens are labor-intensive and time-consuming. The objective of this study was to apply a multiplex PCR for simultaneous detection of the pathogenic bacteria in certain raw and ready-to-eat meat matrices. The tested samples had aerobic plate counts ranging from non-detectable, in chicken nuggets and salami, to 8.36log(10)CFU/g in ground pork. The pH of homogenates spanned from 6.86, in ground beef, to 7.17 in salami. Following a 24-h enrichment, the multiplex PCR assay could concurrently detect the three pathogens at 0.2log(10)CFU/g in ground beef, roast beef, beef frankfurters, chicken nuggets, salami and turkey ham, and 1.2log(10)CFU/g in ground pork. This multiplex PCR offers an efficient microbiological tool for presumptive detection of E. coli O157:H7, Salmonella and Shigella in meat.     

Prevalence and antimicrobial susceptibility of Salmonella isolated from a variety of raw meat sausages in Gaborone (Botswana) retail stores

The objective of the study was to provide baseline data on the prevalence and antimicrobial susceptibility of Salmonella in different types of raw meat sausages directly accessible to the consumers in Gaborone, Botswana. A total of 300 raw sausages comprising 79 beef, 78 pork, 72 chicken, and 71 mutton samples were concurrently analyzed for the presence of Salmonella using a conventional culture method and a validated PCR method. The PCR assay results were in full concordance with those of the conventional culture method for the detection of Salmonella. Sixty-five (21.7%) of 300 samples were positive for Salmonella by both the conventional culture method and PCR assay. Even though more chicken samples contained Salmonella than did any other sausage type, the difference in the presence of Salmonella among the four sausages types was not significant. Eleven serotypes were identified, and Salmonella enterica subsp. salamae II was most prevalent in all the sausage types. Beef sausages generally had higher mesophilic bacterial counts than did the other three sausage types. However, higher microbial counts were not reflective of the presence of salmonellae. Susceptibility of the Salmonella enterica serotypes to 20 antimicrobial agents was determined, and Salmonella Muenchen was resistant to the widest array of agents and was mostly isolated from chicken sausages. Regardless of the meat of origin, all 65 Salmonella isolates were resistant to at least four antimicrobial agents: amikacin, gentamicin, cefuroxime, and tombramycin. This resistance profile group was the most common in all four sausage types, comprising 90% of all Salmonella isolates from beef, 71% from pork, 63% from mutton, and 35% from chicken. These results suggest that raw sausages pose a risk of transmitting multidrug-resistant Salmonella isolates to consumers.     

Aroma development in high pressure treated beef and chicken meat compared to raw and heat treated

Chicken breast and beef muscle were treated at 400 and 600 MPa for 15 min at 5 °C and compared to raw meat and a heated sample (100 °C for 15 min). Vacuum-packed beef meat with a smaller fraction of unsaturated fatty acids showed better oxidative stability during 14 days of cold storage, as shown by a low steady-state level of hydroperoxide values, than vacuum-packed chicken meat. Accordingly, the critical pressures of 400 MPa and 600 MPa for chicken breast and beef sirloin, respectively, were established. Volatiles released after opening of the meat bags or during storage of open meat bags, simulating consumer behaviour, were measured under conditions mimicking eating. Quantitative and olfactory analysis of pressurised meat gave a total of 46 flavour volatiles, mainly alcohols (11), aldehydes (15), and ketones (11), but all in low abundance after 14 days of storage. Overall, beef meat contained less volatiles and in lower abundance (factor of 5) compared to chicken meat. The most important odour active volatiles (GC-O) were well below the detection thresholds necessary to impart a perceivable off-flavour. Lipid oxidation was significantly accelerated during 24 h of cold storage in both cooked chicken and beef when exposed to oxygen, while the pressurised and oxygen-exposed chicken and beef meat remained stable. Pressure treatment of beef and chicken did not induce severe changes of their raw aroma profiles.     

The effect of phytic acid on oxidative stability of raw and cooked meat

The effects of phytic acid addition (0.1, 1 and 5 mM) to pork and beef homogenates on TBARS and metmyoglobin levels in raw meat, and TBARS and heme iron contents in cooked meat during 3 days of storage at 4 °C were investigated. Also, the role of inositol as a potential synergist of IP₆ (phytic acid) was examined. IP₆ effectively decreased the TBARS accumulation in raw and cooked meat homogenates. The metmyoglobin formation was inhibited in raw beef by phytic acid in a dose-dependent manner. The effect of IP₆ was more pronounced in cooked meat than in raw and in cooked beef homogenates more than pork. Inositol did not enhance antioxidant action of phytic acid in minced meat.     

Heat-Resistance of Escherichia Coli O157:H7 in Meat and Poultry as Affected by Product Composition

The effects of fat level and low fat formulation on survival of Escherichia coli O157:H7 isolate 204P heated in ground beef [7%, 10% and 20% fat], pork sausage [7%, 10%, and 30% fat], chicken (3% and 11% fat), and turkey (3% and 11% fat) were determined by D- and z-values. D-values for E. coli 0157:H7 in lowest fat products were lower than in traditional beef and pork products (P < 0.05). Overall, higher fat levels in all products resulted in higher D-values. D₆₀ values (min) ranged from 0.45–0.47 in beef, 0.37–0.55 in pork sausage, 0.38–0.55 in chicken and 0.55–0.58 in turkey. D₅₅ and D₅₀ values were respectively longer. Z-values ranged from 4.4–4.8°C. Product composition affected lethality of heat to E. coli O157:H7.     

Multiplex real-time PCR for the detection and quantification of DNA from beef, pork, chicken and turkey

Many meat products are composed of two or more meat species. To determine the proportion of these meat fractions, a quantitative multiplex PCR was developed for the quantification of beef, pork, chicken and turkey. This system proved its applicability, precision and accuracy in examining different meat products from the market. Thus it allows the efficient control of composed meat products in official food control and production control laboratories.     

Hydroperoxide formation in different lean meats

Peroxide is one of the compounds that are indicated to be toxic in the human digestion system. Lean fresh meat samples were collected from beef, lamb, pork and chicken to investigate their hydroperoxide formation potential. Total peroxides of fresh comminuted raw meat were determined by analysing protein-bound peroxides and hydroperoxide compounds in water–methanol and chloroform extracted phases. The amount of total peroxides was ranked as: beef > pork > lamb > chicken. Hydroperoxide formation was examined at different pH values and at different incubation times, using beef and chicken samples. All peroxides were transient, with a maximum value after 2–4 h of incubation at 37 °C. When pH fell from 7 to 1.5, the different peroxides fell by 10–20%. Non-polar peroxide formation could largely (70%) be described by variation in fatty acid composition and hemin content of the meat, while protein-bound peroxide variation was less explained by these variables. Liposome addition increased (40%) the amount of protein-bound peroxides.     

Determination of soybean proteins in commercial heat-processed meat products prepared with chicken,beef or complex mixtures of meats from different species

The addition of foreign proteins (mainly soybean proteins and milk proteins) to heat-processed meat products is a common practice. This work approaches the determination of additions of soybean proteins in heat-processed meat products prepared with chicken meat, beef meat, and complex mixtures of meats from different species (chicken, pork, beef, and turkey) by perfusion reversed-phase high-performance liquid chromatography. The applied method was previously developed for the determination of soybean proteins in pork and turkey meat products but it has never been tested for the determination of soybean proteins in other heat-processed meat products containing other kinds of meats. This paper demonstrates the validity of this method for the detection of soybean proteins in heat-processed meat products containing different varieties of meats and even in the presence of other foreign proteins such as milk proteins. The specificity and existence of matrix interferences have been checked for these samples and accuracy has been evaluated by the comparison of the soybean protein contents determined by the proposed method and the official ELISA method.