Effect of high pressure processing on the microbiology of skin-vacuum packaged sliced meat products: cooked pork ham, dry cured pork ham and marinated beef loin

High hydrostatic pressure is being increasingly investigated in food processing. It causes microbial inactivation and therefore extends the shelf life and enhances the safety of food products. Yeasts, molds, and vegetative cells of bacteria can be inactivated by pressures in the range of 200 to 700 MPa. Microorganisms are more or less sensitive to pressure depending on several factors such as type, strain and the phase or state of the cells. In general, Gram-positive organisms are usually more resistant than Gram-negative. High pressure processing modifies the permeability of the cell membrane, the ion exchange and causes changes in morphology and biochemical reactions, protein denaturations and inhibition of genetic mechanisms. High pressure has been used successfully to extend the shelf life of high-acid foods such as refrigerated fruit juices, jellies and jams. There is now an increasing interest in the use of this technology to extend the shelf life of low-acid foods such as different types of meat products.

Consumers’ sensory acceptability of pork from immunocastrated male pigs

Boar taint is the off-odour or off flavour of cooked pork. Currently, the most common method of controlling boar taint is surgical castration. However, immunocastration has been used in some parts of the world as an alternative to surgical castration. The aim of this study was to evaluate the sensory acceptability of meat from immunocastrated pigs (IM) compared with meat from females (FE), surgically castrated (CM) and entire males (EM). Twenty animals of each type were evaluated by 201 consumers in 20 sessions. Longissimus thoracis muscle of the different animals was cooked in an oven at 180 °C for 10 min. Consumers scored the odour and the flavour of the meat in a 9-point category scale without an intermediate level. There were no significant differences in consumer’s evaluation of meat from IM, CM, and FE. In contrast, EM meat presented a higher percentage of dissatisfied scores and was significantly (P & 0.05) less accepted than meat from CM, IM and FE. Consumers’ acceptability of EM meat was always lower, independently of its androstenone levels. However meat with low levels of androstenone was more accepted that meat with medium or high levels of this substance. It can be concluded that immunocastration produced pork that was accepted by the consumers, and was indistinguishable from pork from CM or FE.

Surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry: A tool to predict pork quality

Expression of water soluble proteins of fresh pork Longissimus thoracis from 4 pure breed pigs (Duroc, Large White, Landrace, and Piétrain) was studied to identify candidate protein markers for meat quality. Surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (SELDI-TOF-MS) was used to obtain the soluble protein profiles of Longissimus thoracis muscles. The pure breeds showed differences among the studied meat quality traits (pHu, drip loss, androstenone, marbling, intramuscular fat, texture, and moisture), but no significant differences were detected in sensory analysis. Associations between protein peaks obtained with SELDI-TOF-MS and meat quality traits, mainly water holding capacity, texture and skatole were observed. Of these peaks, a total of 10 peaks from CM10 array and 6 peaks from Q10 array were candidate soluble protein markers for pork loin quality. The developed models explained a limited proportion of the variability, however they point out interesting relationships between protein expression and meat quality

Effect of magnesium sulphate and L-tryptophan and genotype on the feed intake, behaviour and meat quality of pigs

Sixty-nine entire male pigs with different halothane genotype (homozygous halothanepositive – nn-, n=36; and homozygous halothane negative – NN-, n=33) were fed with a supplementation of magnesium sulphate (Mg) and/or L-tryptophan (Trp) in the diet for 5days before slaughter. Animals were housed individually and were submitted to stressful ante mortem conditions (mixed in the lorry according to treatments and transported 1h on rough roads). Individual feed intake was recorded during the 5-day treatment. At the abattoir, pig behaviour was assessed in the raceway to the stunning system and during the stunning period by exposure to CO2. Muscle pH, colour, water holding capacity, texture and cathepsin activities were determined to assess meat quality. The number of pigs with an individual feed intake lower than 2kg/day was significantly different among diets (P<0.05; Control: 8.7%; Mg&Trp: 43.5%; Trp:17.4%) and they were considered to have inadequate supplement intake. During the antemortem period, 15.2% of pigs included in the experiment died, and this percentagedecreased to 8.7% in those pigs with a feed intake > 2kg/day, all of them from thestress-sensitive pigs (nn). In general, no differences were observed in the behaviour ofpigs along the corridor leading to the stunning system and inside the CO2 stunningsystem. During the stunning procedure, Trp diet showed shorter periods of muscularexcitation than control and Mg&Trp diets. The combination of a stressful ante mortemtreatment and Mg&Trp supplementation led to carcasses with high incidence of severeskin lesions. Different meat quality results were found when considering all pigs orconsidering only those with adequate supplement intake. In this later case, Trp increased pH45 (6.15) vs Control diet (5.96) in the Longissimus thoracis (LT) muscle (P<0.05) and pH at 24h (Trp: 5.59 vs C: 5.47) led to a higher incidence of dark, firm and dry (DFD) traits in SM muscle (P<0.05). Genotype affected negatively all the meat quality traits. Seventy-five percent of LT and 60.0% of the SM muscles from nn pigs wereclassified as pale, soft and exudative (PSE), while none of the NN pigs showed these traits (P<0.0001). No significant differences were found between genotypes on the incidence of DFD meat. Due to the negative effects observed in the Mg&Trp group in feed intake and carcass quality, the utilization of a mixture of magnesium sulphate and tryptophan is not recommended

Effect of supplementation with MgCO3 and L-tryptophan on the welfare and on the carcass and meat quality of two halothane pig genotypes (NN and nn)

Sixty-one animals with different Halothane genes (homozygous halothane positive, n=34; and homozygous halothane negative, n=27) were fed with three diets (controlgroup, with no supplement; magnesium (Mg) group with 1.28g MgCO3/kg and tryptophan (Trp) group with 5g L-Trp/kg) during the last 5 days before slaughter. Animals were submitted to minimal stress ante mortem conditions. Pig behaviour was recorded at the experimental farm, raceway to the CO2 stunning system and during the stunning period. Corneal reflexes were recorded after stunning as well. There were no differences in feed intake among diets (p>0.05) during the 5 days of treatment. Thehalothane positive (nn) group had lower intake than the halothane negative (NN) group(p<0.01). The behaviour of the pigs in the raceway did not differ (p>0.05) among treatments or halothane genotype. A significant (p<0.001) interaction diet*halothane was found in the time to appear the first retreat attempt during the exposure to the CO2 system. In the nn group, the time of performing the first retreat attempt was later in the Mg (p<0.05) than the Control group. Moreover, in the Mg group, the nn had a later (p<0.05) first retreat attempt than the NN. Thus, Mg supplementation could have a positive effect on welfare of nn pigs. The nn had a lower proportion of animals thatshowed corneal reflexes after stunning than NN, indicating a higher effectiveness of thestunning method in nn pigs. Neither Mg nor Trp affected carcass quality and meat quality parameters, although significant differences were found between genotypes

Microbial spoilage and quality of marinated dark, firm, dry meat

Estudi elaborat a partir d’una estada al Royal Veterinary and Agricultural University of Denmark entre els mesos de Març a Juny del 2006. S’ha investigat l’efecte dels envasats amb atmosferes modificades (MAP), així com la marinació amb vi tint, sobre l’evolució de la contaminació bacteriològica de carns fosques, dures i seques (DFD). Les carns DFD es troben a les canals d’animals que, abans del sacrifici, han estat exposades a activitats musculars prolongades o estrès. Les carns DFD impliquen importants pèrdues econòmiques degut a la contaminació bacteriològica i als problemes tecnològics relacionats amb la alta capacitat de retenció d’aigua. A més a més, és crític per la indústria investigar la diversitat de la contaminació bacteriana, identificar les espècies bacterianes i controlar-les. Però és difícil degut a la inhabilitat per detectar algunes bactèries en medis coneguts, les interaccions entre elles, la complexitat dels tipus de contaminació com són aigua, terra, femtes i l’ambient. La Polymerasa chain reaction- Denaturating Electrophoresis Gel (PCR-DGEE ) pot sobrepassar aquests problemes reflectint la diversitat microbial i les espècies bacterianes. Els resultants han indicat que la varietat bacteriana de la carn incrementava amb els dies d’envasat independentment del mètode d’envasat, però decreixia significativament amb el tractament de marinació amb vi tint. La DGEE ha mostrat diferències en les espècies trobades, indicant canvis en la contaminació bacteriana i les seves característiques en la carn DFD sota els diferents tractaments. Tot i que la marinació és una bona alternativa i solució a la comercialització de carn DFD , estudis de seqüenciació són necessaris per identificar les diferents tipus de bactèries.

Meat quality of ten cattle breeds of the Southwest of Europe

A sample of about 70 young bulls of each of ten beef cattle breeds reared in their typical production systems has been characterised with respect to meat quality traits. Breeds included were Asturiana de los Valles, Asturiana de la Montaña, Avileña-Negra Ibérica, Bruna dels Pirineus, Morucha, Pirenaica and Retinta from Spain, and Aubrac, Gasconne and Salers from France. As was previously showed regarding carcass traits, there exist large differences both between and within breed – systems. In general, rustic breeds tended to present darker and redder meats with higher haematin contents, whereas less precocious and more specialised breeds showed brighter meats with bigger water losses. Protein content was similar, whereas intramuscular fat presented the larger variations both between and within breeds. ICDH content was higher in the more rustic breeds, showing the predominantly oxidative character of their fibres. Texture measurements showed in general large within breed-system variations, the differences between breeds being less evident. Within breed-system, daily gain weight was positively associated with brighter and tender meats. In the range studied, increasing slaughter weight within breed did not have influence on meat quality. Conformation was related to lower water holding capacity and less dry matter and intramuscular fat, as well as to a lower haematin content giving brighter meats. The increase in fatness scores was related to an augment of toughness in meat specialised breeds, although in Avileña-Negra Ibérica breed fatness carcasses were related to more tender meats. Redness parameter a* was positively related to fatter animals and opposed to conformation, the opposite being true for the L* (lightness) parameter. There was a small trend of fatter carcasses to be related to oxidative fibres, whereas the muscular fibres of the more conformed carcasses were more glycolytic. Texture measurements maximum load, maximum stress and toughness were very closely related. Shear force was opposed to tenderness. Losses at cooking were opposed to juiciness, but only in the Spanish breeds. No consistent trends regarding relationships between carcass characteristics and tenderness could be observed. Overall acceptability was primarily related with tenderness and flavour, and later on juiciness.

Bioequivalence of meat products treated with high pressure processing

The effects of high pressure on the composition of food products have not been evaluated extensively. Since, it is necessary to take in consideration the possible effects in basis to the changes induced in the bio molecules by the application of high pressures. The main effect on protein is the denaturation, because the covalent bonds are not affected; however hydrogen bonding, hydrophobic and intermolecular interactions are modified or destroyed. 1 High pressure can modify the activity of some enzymes. If this is done the proteolysis and lipolysis could be more or less intense and the content of free amino acids and fatty acids will be different. This could be related to the bioavailability of these compounds. Low pressures (100 MPa) have been shown to activate some enzymes (monomeric enzymes). Higher pressures induce loss of the enzyme activity. However some enzymes are very stable (ex. Lipase ~ 600 - 1000 MPa). Lipoxygenase is less stable, and there is little information about the effects on antioxidant enzymes. Other important issue is the influence of high pressure on oxidation susceptibility. This could modify the composition of lipids if the degree of the oxidation would have been higher or lower than in the traditional product. Pressure produces the damage of cell membranes favouring the contact between substrates and enzymes, exposure to oxidation of membrane fatty acids and loos of the efficiency of vitamin E. These effects can also affect to protein oxidation. In this study different compounds were analysed to establish the differences between non-treated and high-pressure treated products.

II Workshop on the use of Computed Tomography (CT) in pig carcass classification. Other CT applications: live animals and meat technology, 16-17th April 2009, Monells (Girona), Spain

Es va realitzar el II Workshop en Tomografia Computeritzada (TC) a Monells. El primer dia es va dedicar íntegrament a la utilització del TC en temes de classificació de canals porcines, i el segon dia es va obrir a altres aplicacions del TC, ja sigui en animals vius o en diferents aspectes de qualitat de la carn o els productes carnis. Al workshop hi van assistir 45 persones de 12 països de la UE. The II workshop on the use of Computed Tomography (CT) in pig carcass classification. Other CT applications: live animals and meat technology was held in Monells. The first day it was dedicated to the use of CT in pig carcass classification. The segond day it was open to otehr CT applications, in live animals or in meat and meat products quality. There were 45 assistants of 12 EU countries.

Estimation of lean meat content in pig carcasses using X-ray Computed Tomography and PLS regression

Lean meat percentage (LMP) is an important carcass quality parameter. The aim of this work is to obtain a calibration equation for the Computed Tomography (CT) scans with the Partial Least Square Regression (PLS) technique in order to predict the LMP of the carcass and the different cuts and to study and compare two different methodologies of the selection of the variables (Variable Importance for Projection — VIP- and Stepwise) to be included in the prediction equation. The error of prediction with cross-validation (RMSEPCV) of the LMP obtained with PLS and selection based on VIP value was 0.82% and for stepwise selection it was 0.83%. The prediction of the LMP scanning only the ham had a RMSEPCV of 0.97% and if the ham and the loin were scanned the RMSEPCV was 0.90%. Results indicate that for CT data both VIP and stepwise selection are good methods. Moreover the scanning of only the ham allowed us to obtain a good prediction of the LMP of the whole carcass.

Comparison of different devices for predicting the lean meat percentage of pig carcasses

Lean meat percentage (LMP) is the criterion for carcass classification and it must be measured on line objectively. The aim of this work was to compare the error of the prediction (RMSEP) of the LMP measured with the following different devices: Fat-O-Meat’er (FOM), UltraFOM (UFOM), AUTOFOM and -VCS2000. For this reason the same 99 carcasses were measured using all 4 apparatus and dissected according to the European Reference Method. Moreover a subsample of the carcasses (n=77) were fully scanned with a X-ray Computed Tomography equipment (CT). The RMSEP calculated with cross validation leave-one-out was lower for FOM and AUTOFOM (1.8% and 1.9%, respectively) and higher for UFOM and VCS2000 (2.3% for both devices). The error obtained with CT was the lowest (0.96%) in accordance with previous results, but CT cannot be used on line. It can be concluded that FOM and AUTOFOM presented better accuracy than UFOM and VCS2000.

Effect of magnesium sulphate and L-tryptophan and genotype on the feed intake, behaviour and meat quality of pigs

Sixty-nine entire male pigs with different halothane genotype (homozygous halothane positive – nn –, n=36; and homozygous halothane negative – NN-, n=33) were fed with a supplementation of magnesium sulphate (Mg) and/or L-tryptophan (Trp) in the diet for 5 days before slaughter. Animals were housed individually and were submitted to stressful ante mortem conditions (mixed in the lorry according to treatments and transported 1 hour on rough roads). Individual feed intake was recorded during the 5-d treatment. At the abattoir, pig behaviour was assessed in the raceway to the stunning system and during the stunning period by exposure to CO2. Muscle pH, colour, water holding capacity, texture and cathepsin activities were determined to assess meat quality. The number of pigs with an individual feed intake lower than 2 kg/d was significantly different among diets (P&0.05; Control: 8.7 %; Mg&Trp: 43.5 %; Trp: 17.4 %) and they were considered to have inadequate supplement intake. During the ante mortem period, 15.2 % of pigs included in the experiment died, and this percentage decreased to 8.7 % in those pigs with a feed intake & 2kg/day, all of them from the stress-sensitive pigs (nn). In general, no differences were observed in the behaviour of pigs along the corridor leading to the stunning system and inside the CO2 stunning system. During the stunning procedure, Trp diet showed shorter periods of muscular excitation than control and Mg&Trp diets. The combination of a stressful ante mortem treatment and Mg&Trp supplementation led to carcasses with high incidence of severe skin lesions. Different meat quality results were found when considering all pigs or considering only those with adequate supplement intake. In this later case, Trp increased pH45 (6.15) vs Control diet (5.96) in the Longissimus thoracis (LT) muscle (P&0.05) and pH at 24h (Trp: 5.59 vs C: 5.47) led to a higher incidence of dark, firm and exudative (DFD) traits in SM muscle (P&0.05). Genotype affected negatively all the meat quality traits. Seventy-five percent of LT and 60.0 % of the SM muscles from nn pigs were classified as pale, soft and exudative (PSE), while none of the NN pigs showed these traits (P&0.0001). No significant differences were found between genotypes on the incidence of DFD meat. Due to the negative effects observed in the Mg&Trp group in feed intake and carcass quality, the utilization of a mixture of magnesium sulphate and tryptophan is not recommended.

Pork Value Chains: A Comparison of Catalonia, Spain and Manitoba, Canada

The purpose of this paper is to provide a comparative analysis of pork value chains in Catalonia, Spain and Manitoba, Canada. Intensive hog production models were implemented in Catalonia in the 1960s as a result of agriculture crises and fostered by feedstuffs factories. The expansion of the hog sector in Manitoba is more recent (in the 1990s) and brought about in large part by the opening of the Maple Leaf Meats processing plant in Brandon, Manitoba. This plant is capable of processing 90,000 hogs per week. Both hog production models ‐ the ‘older’ one in Catalonia (Spain) and the ‘newer’ in Manitoba‐ have been, until recently, examples of success. Inventories and production have been increasing substantially and both regions have proven to have great export potential. Recently, however, tensions have been developing with the hog production models of both regions, particularly as they relate to environmental concerns. The purpose of the paper is to compare the value chains with respect to their origins (e.g. supply a growing demand for pork, ensure farm profitability) and present states (e.g. environmental concerns, profitability). Keywords: pork value chain, hog farms, agri‐food studies. JEL: Q10, Q13, O57

Quality assurance mechanisms in agrifood: The case of the Spanish fresh meat sector

The largest fresh meat brand names in Spain are analyzed here to studyhow quality is signaled in agribusiness and how the underlying quality-assurance organizations work. Results show, first, that organizationalform varies according to the specialization of the brand name.Publicly-controlled brand names are grounded on market contracting withindividual producers, providing stronger incentives. In contrast,private brands rely more on hierarchy, taking advantage of itssuperiority in solving specific coordination problems. Second, theseemingly redundant coexistence of several quality indicators for agiven product is explained in efficiency terms. Multiple brands areshown to be complementary, given their specialization in guaranteeingdifferent attributes of the product.

Use of palm-oil by-products in chicken and rabbit feeds: effect on the fatty acid and tocol composition of meat, liver and plasma

This study was undertaken in the framework of a larger European project dealing with the characterization of fat co- and by-products from the food chain, available for feed uses. In this study, we compare the effects, on the fatty acid (FA) and tocol composition of chicken and rabbit tissues, of the addition to feeds of a palm fatty acid distillate, very low in trans fatty acids (TFA), and two levels of the corresponding hydrogenated by-product, containing intermediate and high levels of TFA. Thus, the experimental design included three treatments, formulated for each species, containing the three levels of TFA defined above. Obviously, due to the use of hydrogenated fats, the levels of saturated fatty acids (SFA) show clear differences between the three dietary treatments. The results show that diets high in TFA (76 g/kg fat) compared with those low in TFA (4.4 g/kg fat) led to a lower content of tocopherols and tocotrienols in tissues, although these differences were not always statistically significant, and show a different pattern for rabbit and chicken. The TFA content in meat, liver and plasma increased from low-to-high TFA feeds in both chicken and rabbit. However, the transfer ratios from feed were not proportional to the TFA levels in feeds, reflecting certain differences according to the animal species. Moreover, feeds containing fats higher in TFA induced significant changes in tissue SFA, monounsaturated fatty acids and polyunsaturated fatty acids composition, but different patterns can be described for chicken and rabbit and for each type of tissue.