Head Meat Research Articles

UK bovine carcass meat consumed as burgers, sausages and other meat products: by birth cohort and gender

The most likely human exposure to bovine spongiform encephalopathy (BSE) is dietary, through beef mechanically recovered meat (MRM) and head meat used in burgers, sausages and other meat products. The majority, reportedly 90% of beef MRM and 80% of head meat, was used in burgers. To enable quantification of UK dietary exposure to BSE, we quantified bovine carcass meat consumed as burgers, sausages and other meat products by birth cohort, gender and calendar period (1980-1989, 1990-1996). Synthesis of dietary data (cross-sectional National Dietary and Nutrition Surveys, and serial National Food Surveys and Realeat Surveys) to simulate weekly consumption by one-thousandth of the UK population in each year from 1980 to 1996. In 1980-1989, the highest number of consumers (per 7 days) of all three food groups was in the 1940-1969 birth cohort - averaging 3.7 million male consumers of burgers, 2.6 million of sausages and 8.5 million of other meat products. The post-1969 birth cohort had the next highest number of consumers of burgers (1.8 million males). In 1990-1996, consumer numbers declined for the two older cohorts, most strikingly for burgers (down to 2.5 million males in the 1940-1969 cohort). The 1940-1969 cohort retained the highest number of consumers of sausages and other meat products, and second place for burgers. Male consumption was higher, even in the pre-1940 birth cohort where, for demographic reasons, female consumers outnumbered males. In the post-1969 birth cohort, female consumption of bovine carcass meat weight as burgers increased from 68 tonnes in 1980-1989 to 81 tonnes in 1990-1996, and male consumption increased more markedly (by 41%) from 84 tonnes to 119 tonnes; and similarly for other meat products. Properly marshalled age-group and gender-specific consumption data contribute to a clearer understanding of the demography of those who were at risk of dietary exposure to BSE and of when their exposure intensity was greatest. Other countries may need to consider using dietary data to model their human BSE exposure from UK and other BSE-affected regions.

Detection of mechanically recovered meat and head meat from cattle in ground beef mixtures by multivariate analysis of isoelectric focusing protein profiles

The present work investigates the possibility of constructing a multivariate calibration model for predicting the composition of ground beef with respect to different meat quality types, based on intensity profiles from isoelectric focusing of water-soluble proteins. Beef mixtures containing various amounts of mechanically recovered meat, head meat and production meat from beef, were analysed by isoelectric focusing in immobilised pH-gradients. The gels were photographed and the images transferred to a digital format. By simple image processing procedures, background colour was virtually eliminated and signal strength was improved to a considerable degree. Multivariate analysis of protein profiles from the gels gave models explaining 75 to 90% of variance in sample composition. Manually deboned meat was explained to the highest degree, and with a precision of 7%. Two different qualities of mechanically recovered meat could be detected even when treated as one category. The present approach needs further refinement, but seems applicable for detecting intentional substitution of high quality meat products with low-price raw materials. One advantage of the approach is that evaluation of samples is not dependent on specific knowledge on the individual components to be analysed, so that such analytical methods are relatively easy to implement in any standard laboratory.

Influence of body condition score on by-product yield and value from cull beef cows.

Mature beef cows (n = 122) representing British and Continental phenotypes were slaughtered to measure the influence of body condition score (BCS) on by-product yield and value. All cows were weighed and assigned BCS, based on a 9-point scale, 24 h before slaughter. By-product weights were obtained during the slaughter process and included blood, feet (with hooves attached), oxlips, tongue, gullet, trachea, cheek meat, head meat, skull, tripe, honeycomb tripe, large and small intestines, spleen, mesenteric fat, weasand meat, kidneys, heart, lungs, and oxtail. By-product yields were calculated as a percentage of the animal's live weight taken 24 h before slaughter. By-product values were computed by multiplying the weight of each piece removed during the slaughter process by the 1997 average price. Live weight increased linearly (P<.001) as BCS increased from 2 to 8, whereas Continental cows were approximately 86 kg heavier (P<.05) at slaughter than British cows. Cows assigned a BCS of 2 or 3 had greater (P<.05) skull, feet, tongue, tripe, honeycomb tripe, trachea, and lung yields than cows assigned a BCS of 4 or higher. On the other hand, BCS-7 and 8 cows had greater (P<.05) weights and yields of large intestines and mesenteric fat than cows given a BCS of 6 or lower. The feet, trachea, lungs, and bone meal from BCS-2 cows had the greatest (P<.05) value, whereas the value of the large intestine, oxtail, and mesenteric fat was highest (P<.05) for BCS-7 and 8 cows. Weight, yield, and value of the skull, head meat, and feet were greater (P<.05) for Continental cows than British cows. Total by-product value was quadratically (P<.001) related to BCS. Cows assigned a BCS of 5 had lower (P<.05) total by-product values than either BCS-2 or BCS-7 and 8 cows. Drop credit for BCS-2 cows was greater (P<.05) than BCS-3, 4, 5, and 6 cows, with cows assigned a BCS of 7 and 8 having intermediate drop credit values. Continental cows tended to have greater (P<.10) total by-product and drop credit values than British cows. Information from this study indicated that the BCS of cows at the time of slaughter had a profound influence on by-product yields and, more importantly, values of by-products that are credited back against the cost of production to the beef cattle producer.

Microbiology of the Swine Head Meat Deboning Process

The microbiology of swine head meat was evaluated by comparing the levels of aerobic plate count (APC), coliforms, and Escherichia coli as well as the incidence and levels of Salmonella spp. in swine head meat harvested by either the old or a new improved procedure. Based on 144 samples (72 by each procedure), the levels of APC, coliforms, and E. coli were 4.52 ± 0.26, 2.37 ± 0.42, and 2.25±0.42 log10 CFU/g respectively, regardless of the procedure used for harvesting the meat. The incidence (27/72 versus 28/72) and MPN levels (4 to 93 versus 4 to 1100) of Salmonella spp. determined by the Bacteriological Analytical Manual (BAM) methods also were the same for meat obtained using either the old or the new procedure. The BAM method detected a higher incidence of Salmonella spp. (55/144) than other methods, PCR (38/144; BAX, Du Pont) or DNA hybridization (41/144; Gene-Trak). Time of harvesting during the processing day or site of origin of the head meat (cheek versus tongue versus back of head) had no effect on the incidence of Salmonella spp. The data in this study indicate that the levels of bacteria encountered in swine head meat are a reflection of the harvesting procedures themselves, as well as levels in and around the head and oral cavity of swine.

Slaughter pigs and pork as a source of human pathogenic Yersinia enterocolitica

Pathogenic Yersinia enterocolitica strains (serogroups 0 : 3;0 :9 and 0 :5,27) were isolated from 36 (42%) of 86 porcine tonsils, 8 (20%) of 40 tongues, 17 (17%) of 100 rectal swabs and from 4 (1%) of 400 pork samples. Pathogenic Yersinia strains were not isolated from samples of 210 pig carcasses and from 20 samples of porcine head meat. These results confirm that pigs are an important reservoir of pathogenic Y. enterocolitica. However, contamination of carcasses during the slaughtering process with Yersinia from either faecal material or from the tonsillary region does not seem to occur frequently and this may also explain the low contamination rate of pathogenic Y. enterocolitica found for pork. For the isolation of pathogenic Y. enterocolitica strains from foods, enrichment in irgasan-ticarcillin-chlorate broth (ITC) and isolation on SS-deoxycholate-calcium agar (SSDC) is recommended.

Yersinia enterocolitica in food hygiene

Yersinia enterocolitica and Yersinia enterocolitica-like bacteria constitute a fairly heterogenous group of bacteria which both well-established pathogens and a range of environmetnal strains which are ubiquitous in terrestrial and freshwater ecosystems. Pathogenic significance in man is mainly associated with a few serogroups (O:3, O:9, O:8, O:5,27). The pathogenic serogroups show different geographical distributions. The development of isolation procedures which clearly differentiate pathogenic from non-pathogenic variants has been difficult. Of special significance in food hygiene is the ability of Y. enterocolitica to grow in refrigerated foods. There is strong indirect evidence that pigs and food products of porcine origin are the major sources for human infection with Y. enterocolitica serogroups O:3 and O:9, the dominant human pathogens in most of the world. The rservoir(s) for serogroup O:8, which prevails in the U.S.A., is uncertain. The pig is the only animal consumed by man which regularly harbours pathogenic Y. enterocolitica. Improved isolation methods and DNA colony hybridization using genetic probes has indicated that the prevalence of pathogenic Y. enterocolitica in pork products is substantially higher than previously suggested. Prevention and control measures should focus on information of people involved in food processing and preparation and on the improvement of hygiene during slaughtering of swine. Important critical control points at the stage of slaughter are: (i) circumanal incision and removal of intestines, (ii) excision of the tongue, pharynx, and particularly the tonsils, (iii) post-mortem meat inspection procedures which involve incision of the mandibular lymph nodes, and (iv) deboning of head meat.