The effect of electrical stimulation on the water-holding, capacity and protein denaturation of two bovine muscles.

The effect of low-voltage electrical stimulation on the water-holding capacity and protein denaturation of bovine longissimus thoracis and semimembranosus was studied in eight electrically stimulated (85 V, 14 Hz, 15 s; immediately after slaughter) and eight nonstimulated Friesian Holstein bull carcasses. At 24 h postmortem longissimus thoracis and semimembranosus were sampled for drip loss, thaw loss, filter paper wetness, myofibrillar water-holding capacity, protein content of drip, protein solubility, myofibrillar ATPase-activities, and bound phosphorylase. Electrical stimulation resulted in higher (P < .05) drip losses and filter paper wetness and lower (P < .05) myofibrillar water-holding capacity of semimembranous samples. The increased drip loss coincided with decreased (P < .05) sarcoplasmic protein solubility, decreased (P < .05) myofibrillar ATPase-activity, and decreased (P < .05) protein concentration of drip. In the longissimus thoracis, electrical stimulation resulted in a lower (P < .05) myofibrillar water-holding capacity. However, this was not reflected in higher drip losses. In this muscle, only a decreased (P < .05) sarcoplasmic protein solubility and increased (P < .05) amount of bound phosphorylase was observed. The results indicated that the negative effect of electrical stimulation on drip loss is possibly the result of myosin denaturation, which is determined by postmortem pH and temperature fall and thus varies by muscle studied. Sarcoplasmic protein denaturation seemed not to be involved in determining water-holding capacity.

Variation in post-mortem rate of glycolyis does not necessarily affect drip loss of non-stimulated veal.

In this study the effect of the rate of post mortem pH fall on the water-holding capacity of meat from moderately chilled veal carcasses was investigated. Also the relationship between muscle protein denaturation and drip loss of veal was examined. Three groups of 10 Friesian Holstein male veal calves each were selected on the basis of their pH in M. longissimus thoracis et lumborum (LTL) at 3 hr post mortem (pH(3)): (1) fast pH-fall, pH(3) < 6.2; (2) intermediate pH-fall, 6.5 < pH(3) < 6.6; (3) slow pH-fall, pH(3) > 6.7. After 48 hr of chilling the LTL was excised from the carcass and sampled for determination of drip loss, filter paper wetness, sarcomere length, protein solubility and transmission value. Differences in pH(3) were not associated with differences in drip loss, filter paper wetness or differences in protein denaturation. It is suggested that at the relatively high veal carcass chilling rate the effect of rate of pH-fall on protein denaturation and thus on drip loss is negligible. Drip loss of veal was highly correlated with both solubility of sarcoplasmic (r = -0.67; p < 0.001) and total muscle protein (r = -0.54; p < 0.01) and with transmission values (r = 0.66; p < 0.001). These results indicate that protein denaturation measurements may be a good predictor for drip loss of veal.

The transmission of campylobacter in piggeries; an epidemiological study.

The campylobacter infection of 10 sows and their piglets was monitored. These pigs were kept on two multiplier farms. Rectal faeces samples were taken from the sows shortly before littering and at different intervals after littering. Swab samples of rectal content were taken from six piglets per sow at different intervals after birth. Nine sows were shown to be infected with campylobacter before litter and all sows after litter, with an average colony count of 4.1 in log N g-1 of faeces. Half of the piglets became infected with campylobacter during the first week of life and 85%, after four weeks. Two genetic subtyping methods (ERIC-PCR and RFLP) were used to study the relationships between campylobacter isolates from sows and piglets. A large diversity of campylobacter subtypes was found. Nevertheless, piglets and their mothers often harboured campylobacter isolates with identical genetic subtyping profiles, suggesting that piglets become infected via their mothers. However, observed similarities in genetic subtyping profiles between campylobacters isolated on different farms made this difficult to prove.

Effect of dantrolene treatment on muscle metabolism and meat quality of anesthetized pigs of different halothane genotypes.

Muscle metabolism was studied in pigs of different halothane genotypes by taking blood and muscle biopsy samples during a 45-min preslaughter period of anesthesia. Dantrolene was administered to half the pigs of each genotype to investigate whether possible differences in muscle metabolism could be explained by differences in resting myoplasmic calcium concentrations. Dantrolene influenced muscle metabolism of all halothane genotypes to the same extent, leading to higher (P < .05) glycogen and creatine phosphate concentrations and lower (P < .05) lactate and creatine concentrations. Dantrolene could not reduce the small but significant (P < .05) differences observed in resting muscle metabolism between the genotypes, and halothane-positive pigs had lower (P < .05) glycogen and creatine phosphate contents. Postmortem muscle metabolism showed differences (P < .05) between the three halothane genotypes, with the highest rate of glycolysis in halothane-positive pigs. Dantrolene resulted in a significantly slower (P < .05) glycogen and creatine-P breakdown, which led to a less rapid (P < .05) accumulation of lactate and creatine in both muscles. Meat quality characteristics differed between the halothane genotypes but no PSE meat was detected. Dantrolene administration resulted in an elevation (P < .05) of the pH in the longissimus lumborum and in lower (P < .05) rigor values of the semimembranosus, both measured at 45 min after slaughter. Water-holding capacity was higher (P < .05) and Hunter L*-values lower (P < .05) is dantrolene-treated pigs than in the control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

[Quality care in meat production. 'From Von Ostertag to total quality care']. / Kwaliteitszorg in de vleesproduktie. 'Van Von Ostertag naar totale kwaliteitszorg'.

Von Ostertag developed the scientific basis for the system of meat inspection which is still applied over practically the whole world. The decision as to whether meat is fit for human consumption is based on observations made by the veterinarian or his/her assistant before and after slaughter. This system has worked well for years, particularly in the time when various infectious zoonoses were important. Recently, however, the system has been found more and more lacking. For example protection of the consumer from residues and enteropathogenic microorganisms is insufficient. A new analysis of the risks, which are, in fact what meat inspection is about, must be carried out. The costs of inspection are no longer considered to be in the right proportion to the actual level of public health protection. It is useful and necessary to provide the consumer with adequate guarantees, not only with respect to safety, but also with respect to the quality of the products and even the way in which they are produced (environmental aspects, well-being of animals, responsible use of feedstuffs and animal handling systems, etc.). The situation in the animal production sector (health status of the herd, animal health care, consumer/market orientated production, etc.) also makes a different set-up necessary. The traditional meat inspection as the last step in animal production must make way for a system whereby the whole of production can be taken into account and the consumer can be given a total package of all relevant desired guarantees, paired with all relevant information on production methods and products.

Microbial and nutritional aspects of feeding fermented feed (poultry by-products) to pigs.

Broiler by-products (heads, feet, and viscera) mixed with 4% dextrose were pasteurized for 4 min at 90 degrees C core temperature, cooled to 20 degrees C, and fermented with Lactobacillus plantarum as starter culture. These fermented poultry by-products were fed to 12 individually housed fattening pigs as part (17.6% of the dry matter) of their fattening ration, the remainder composed of compound pig feed. Control pigs received a compound pig feed only. Both groups of pigs were fed restrictively on the basis of body weight. The technical results of the pigs fed the experimental diet showed a significantly improved feed:gain ratio (2.46 vs 2.57), a significantly higher carcass weight (86.1 vs 81.8 kg), a lower meat percentage (50.9 vs 52.5%) and an increased backfat thickness (21.5 vs 18.7%). The bacterial flora in the intestinal tract of the pigs fed the experimental diet differed significantly from the control animals. Decreased colony counts of mesophilic aerobic bacteria, Enterobacteriaceae, enterococci and lactobacilli were found in the rectal content and the prevalence of salmonella was lower. It is suggested that the improved feed:gain ratio and the reduced bacterial activity of the measured groups of bacteria is a result of 1) the higher energy content of the diet, and(or) 2) an assumed enhanced digestibility of nutritional components in the diet, and(or) 3) the lower incidence of diarrhea in the pigs fed with fermented poultry by-products. This resulted in a lower contamination level of enteropathogenic bacteria like, salmonella and Escherichia coli, in the gastro-intestinal tract of the pigs fed fermented poultry by-products.

Efficacy of current EC meat inspection procedures and some proposed revisions with respect to microbiological safety: a critical review.

This paper presents an evaluation of the current EC meat inspection procedures, and some of their proposed revisions, in relation to their efficacy in assuring the microbiological safety and quality of meat, and the difficulties for health authorities and industry in providing such an assurance. It is concluded that neither the current nor the proposed revisions of ante and post mortem meat inspection procedures alone are sufficient, and that only integrated approaches, applied to each step of animal and meat production, will lead to better quality meat. Furthermore, for the design of a really effective and flexible long-term system of safety and quality assurance it is necessary to undertake a formal quantitative assessment of risk.

Fermentation of raw poultry byproducts for animal nutrition.

In this study, the fermentation of raw, inedible poultry byproducts mixed with sugarbeet pulp and dextrose and inoculated with Lactobacillus plantarum and(or) Enteroccocus faecium resulted in a drop of pH in the byproducts to approximately 4.0 to 4.5 within 48 h. To keep the fermented product stable for a period of 21 d, the addition of > or = 3% (wt/wt) of a fermentable carbohydrate was necessary. With a high inoculation level of approximately 10(8) to 10(9) L. plantarum per gram, or with acidification of the initial mixture with .4% lactic acid, the number of Enterobacteriaceae decreased faster than with inoculation at 10(5) L. plantarum per gram, or without initial acidification. After 21 d of fermentation, a high level of enzymatic breakdown of proteins and amino acids was observed: the nonprotein N level increased from 5% to between 15 and 40% of total N and the volatile N level increased from 1% to between 3 and 11% of total N. An increase in histamine, cadaverine, and putrescine was also observed. Despite the technological measures taken, such as the application of a high inoculum of starter culture and initial acidification with .4% lactic acid, this amino acid breakdown could not be reduced to an acceptable level. These results suggest that, because of biochemical deterioration, fermentation alone is not a useful method of preservation of raw poultry byproducts.

The feeding of raw, fermented poultry byproducts: using mink as a model.

In this study, the safety of fermentation as a method of preservation of raw animal byproducts used for animal nutrition was tested. Two feeding trials with mink, as a model for nonruminant animals, were carried out. In the first trial mink were given a fermented diet composed of raw poultry and fish byproducts supplemented with cereals, glucose, lactic acid, premix, and starter culture (Lactobacillus plantarum and Enterococcus faecium). These mink failed to deliver kits, and 7 of the 30 females in the test group died. At autopsy no specific cause of death could be diagnosed, although all the dead mink showed symptoms of cachexia. In a second trial, a group of mink kits, during the growth period, was given a diet composed of fermented poultry byproducts, just before feeding mixed with raw fish. The weight gain of the mink in the test group decreased statistically compared with that of the control group, mainly for the male members of the group. From the end of October until the beginning of November, during pelt priming, some mink showed symptoms of severe weight loss. It is suggested that the measured increase of amino acid breakdown, and(or) the acidic pH of the fermented diet, caused these unfavorable results. To examine the effect of the fermented diet on the gut flora, fecal samples were analyzed. The fermented diet changed the composition of the gut flora significantly. In the group that received the fermented diet the number of lactobacilli and the mesophilic aerobic count increased and the number of Enterobacteriaceae and enterococci decreased compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Proteolysis and amino acid breakdown of heated and irradiated poultry byproducts and muscle tissue.

As a result of intensification and centralization of poultry slaughtering, the amount of slaughter byproducts produced at a single location is increasing. These byproducts are rich in protein, fat, and vitamins and, therefore, constitute a potentially useful raw material for use as animal feed. To maintain the nutritive value of these byproducts they should be processed to minimize or eliminate degenerative changes that reduce the feed value of the product. In this paper amino acid breakdown in slaughter-fresh poultry viscera, heads, and breast meat is studied as a model. Initial amino acid breakdown in viscera was observed (also when bacterial growth was excluded by gamma-irradiation), which resulted in high levels of total volatile N and cadaverine. Putrescine was produced only in viscera after bacterial proliferation. In heads and breast meat, no production of metabolites of amino acid degradation was observed as a result of initial enzymatic activity. It is concluded that during preservation of poultry byproducts not only bacterial proliferation, but also enzymatic breakdown of amino acids, must be prevented.

Effect of preslaughter anesthesia on muscle metabolism and meat quality of pigs of different halothane genotypes.

Pigs of different halothane genotypes were anesthetized 45 min before slaughter. During the period of anesthesia blood samples and muscle biopsy samples were taken to investigate muscle energy metabolism by measuring different metabolites. After exsanguination, the same metabolites and some meat quality characteristics were determined. Minimal differences in resting muscle metabolism seemed to exist between the halothane genotypes. Some significant differences in ante- and postmortem metabolism were found, particularly in creatine and lactate concentrations, but these were not reflected in ultimate meat quality. None of the pigs showed PSE meat and there were no differences in muscle pH and temperature at 45 min and 18 h postmortem. However, rigor, drip loss, and color still showed a significant genotype effect. It was concluded that due to the method of anesthesia there were no differences in muscle metabolism at the moment of slaughter. This may have led to a more uniform ultimate meat quality between pigs differing in their genetic susceptibility toward stress. There were differences in color and drip loss between the halothane genotypes that cannot be explained by differences in pH and carcass temperature at 45 min postmortem.

Use of information from pig finishing herds for meat inspection purposes.

In a field trial on Integrated Quality Control of finishing pigs we evaluated information written on Quality Information Cards (QUIC) for meat inspection purposes. These cards were sent with 3747 shipments of pigs going from the finishing herd to the slaughterhouse. Pig suppliers answered five questions dealing with health problems and the use of drugs during the finishing period. By comparing QUIC answers to recorded post-mortem abnormalities, we found that the information on the QUIC had some, albeit low, predictive value with respect to the abnormalities 'arthritis', 'condemned liver' and lung lesions. Shipments without a QUIC or with a faulty QUIC were considered 'suspect' because higher levels of abnormalities were found in these shipments. These results indicate the potential use of a QUIC.

Slaughter by-products: problems, preliminary research and possible solutions.

The collection, storage, disposal and processing of slaughterhouse by-products is an important part of veterinary care in regions with intensive animal husbandry and meat production. Transmission of diseases and environmental pollution through an improper and/or incorrect handling of slaughterhouse by-products needs to be prevented. The use of animal by-products as feedstuff could be of economical benefit to slaughterhouses and could add nutritive value to animal feed. As a results of the centralisation and intensification of slaughtering, the amount of slaughter by-products produced at a single location is increasing. Until now, hardly any attention, in practice or in research, has been paid to the collection and disposal of these by-products. There are important socio-economic reasons to increase scientific knowledge about the handling of slaughter by-products. Several animal by-products were contaminated with Salmonella. We also showed that rapid breakdown of amino acids in poultry by-products occurs during storage at 20 degrees C. It is concluded that as far as safety, environmental care and nutritive value of animal by-products is concerned, diversification and separation of slaughter by-product collection, storage, disposal and processing is necessary. Measures at source, the slaughterline, and some technologies are suggested for future use.

A Comparative Study Into Procedures for Postmortem Inspection for Finishing Pigs.

A postmortem meat inspection system based primarily on visual inspection without palpation or incision was compared with regular meat inspection procedures based on European Community (EC) regulations, which consists of visual inspection, palpation, and incision of organs. Two experiments included 31,682 finishing pigs. Three inspection procedures were followed: visual, i.e., an inspection without manipulation of the carcass; regular, i.e., based on EC regulations; and extra, i.e., based on EC regulations with more time allowed for the inspection. The reproducibility and accuracy of the visual and regular inspection methods were compared with those of the extra inspection. Twelve postmortem abnormalities and four additional findings were compared. The reproducibility of the visual inspection, measured with Cohen's kappa (CK), was poor to fair (CK from 0.14 to 0.64), and the regular inspection also had a poor to fair reproducibility (CK from 0.24 to 0.73). The specificity and sensitivity of the visual and regular inspection methods did not differ significantly for most of the abnormalities and additional findings. The sensitivity was low (range 0-76%) and the number of false-negative findings was sometimes high. It can be concluded that many abnormalities and additional findings are detected equally well by visual and regular postmortem inspection procedures. It is concluded that since both inspection procedures are far from perfect, risk assessment should be performed.