Numerical taxonomy of psychrotrophic lactic acid bacteria from prepacked meat and meat products

Ninety-four strains of lactic acid bateria isolated from refrigerated, prepacked meat and meat products were together with 59 reference strains of Brochothrix, Lactobacillus, Leuconostoc, Pediococcus and Streptococcus phenotypically classfied, using 96 unit characters. Data were examined using Simple Matching (S_SM) or Jaccard coefficient (S_J), and unweighted pair group algorithm with arithmetic averages. Twenty-three clusters with two or more members were defined at the 84% S_SM-similarity level which corresponded to the S_J-similarity level of 61%. Based on S_SM, most field strains were included in nine clusters, and with three unsignificant exceptions these contained no reference strains. The field clusters were designated Carnobacterium piscicola (cluster 1; 5% of field isolates), Carnobacterium divergens(cluster 2; 9% of field isolates), Leuconostoc (cluster 9; 18% of field isolates) and Lactobacillus (cluster 4, 10, 11, 12, 13 and 14; together 60% of field isolates). The Lactobacillus clusters had many features in common with cluster II of Shaw & Harding (1984). Phenotypical characteristics of major clusters are given. The S_SM and S_J based classifications basically coincided for the field strains; the exception was cluster 4 which now were split in two parts. Fourteen clusters were made up of mainly reference strains (S_SM). Most of them included more than one type strain on species level; exceptions were Brochothrix thermosphacta (cluster 3), Lactobacillus salivarius (cluster 17) and Leuconostoc mesenteroides (cluster 18). Several rearrangements were seen amongst the clusters of the reference strains when S_J, instead of S_SM, was used for clustering.     

Effect of slaughter age on foal carcass traits and meat quality

Meat has played a crucial role in human evolution and is an important component of a healthy and well-balanced diet due to its nutritional richness. Recent studies have shown that horsemeat may be considered as an alternative to other meat (such as beef or pork), and it may have a positive effect on human health from a nutritional point of view. This research was conducted to characterize the carcass measurement, meat quality (chemical composition, colour characteristics and textural traits) and nutritional value (fatty acid and amino acid composition) of foals slaughtered at 8 and 11 months of age (8 and 11 m groups). For this study, a total of 21 foals (10 and 11 animals from the 8 and 11-m groups, respectively) were used. The results obtained showed a positive influence on carcass characteristics with an increase in slaughter age, because 11 m animals had slightly higher values of live (275 v. 247 kg) and carcass weights (148 v. 133 kg), length of leg (72.86 v. 69.85 cm) and carcass (100.41 v. 96.30 cm) and perimeter of leg (97.68 v. 89.22 cm) compared with animals from the 8-m group. Regarding meat quality, only Fe-haeme and cholesterol content in chemical composition and luminosity (L*) in colour parameters showed significant differences. Foals from the 8-m group had the highest content of cholesterol (0.47 v. 0.28 mg/100 g of meat) and luminosity values (39.66 v. 37.88) and the lowest content of ash (1.20% v. 1.40%). In fatty acids content, only five out of 23 fatty acids showed differences between the two groups. However, an interesting change in the fatty acid profile occurred with an increase in the slaughter age. Foals from the 8-m group had the highest values of α-linolenic acid and n-3 fatty acids and the lowest values of linoleic and n-6 fatty acids, which is an interesting fact from a health point of view. Finally, slaughter age had no statistical influence on textural properties or amino acid content. As a main conclusion, animals slaughtered at 8 months of age had higher nutritional quality meat (with higher content of n-3 fatty acids) than meat from foals slaughtered at 11 months of age. The slaughter of animals at 8 months of age also reduced production costs because they ate a smaller amount of commercial fodder.     

Implications of white striping and spaghetti meat abnormalities on meat quality and histological features in broilers

During the past few years, there has been an increasing prevalence of broiler breast muscle abnormalities, such as white striping (WS) and wooden breast conditions. More recently, a new muscular abnormality termed as spaghetti meat (SM) because of the altered structural integrity of the Pectoralis major muscle often associated with WS has emerged. Thus, this study aimed at evaluating the effects of WS and SM conditions, occurring alone or combined within the same P. major muscle, on meat quality traits and muscle histology. In two replications, 96 P. major muscles were classified into four classes: normal (N), WS, SM and WS/SM. The whole fillet was used for weight assessment and morphometric measurements, then each sample was cut in order to separate the superficial layer from the deep one and used to evaluate proximate composition, histological features, nuclear magnetic resonance relaxation times, functional properties and both myofibrillar and sarcoplasmic proteins profile. Fillets affected by WS and SM abnormalities exhibited higher weights and increased thickness and length. SM condition was associated with a relevant decrease in protein content coupled with a significant increase in moisture level, whereas fat content was affected only by the simultaneous presence of WS. Histological evaluations revealed that abnormal samples were characterized by several degenerative aspects that almost completely concerned the superficial layer of the fillets. White striped fillets exhibited necrosis and lysis of fibers, fibrosis, lipidosis, loss of cross striation and vacuolar degeneration. Moreover, SM samples were characterized by poor fiber uniformity and a progressive rarefaction of the endo- and peri-mysial connective tissue, whereas WS/SM fillets showed intermediate histological features. Nuclear magnetic resonance relaxation analysis revealed a higher proportion of extra-myofibrillar water in the superficial section of all the abnormal fillets, especially in SM samples, which consequently led to a reduction of the water holding capacity of meat. As for functional properties, abnormal fillets exhibited a lower protein solubility and higher ultimate pH values on both the superficial and deep sections. Although abnormal fillets exhibited higher yellowness values, no relevant effect on meat color was observed. The occurrence of WS and SM abnormalities led to increased carbonylation levels and more intense proteolytic processes. Overall, muscle abnormalities mainly affect the superficial layer of P. major muscle and particularly the occurrence of SM myopathy seems to implicate a more pronounced modification of meat quality traits than the mere presence of WS.     

Implications of white striping and wooden breast abnormalities on quality traits of raw and marinated chicken meat

One of the consequences of intense genetic selection for growth of poultry is the recent appearance of abnormalities in chicken breast muscles, such as white striping (characterised by superficial white striations) and wooden breast (characterised by pale and bulged areas with substantial hardness). The aim of this study was to evaluate the quality traits of chicken fillets affected by white striping and wooden breast abnormalities. In two replications, 192 fillets were divided into the following four classes: normal (n=48; absence of any visual defects), white striping (n=48, presence of white striations), wooden breast (n=48; diffusely presence of hardened areas) and white striping/wooden breast (n=48; fillets affected by both abnormalities). Morphology, raw meat texture and technological properties were assessed in both unprocessed (pH, colour, drip loss, cooking loss and cooked meat shear force) and marinated meat (marinade uptake, purge loss, cooking loss and cooked meat shear force). Fillets affected by white striping, wooden breast or both abnormalities exhibited higher breast weights compared with normal fillets (305.5, 298.7, 318.3 and 244.7 g, respectively; P<0.001). Wooden breast, either alone or in combination with white striping, was associated with a significant (P<0.001) increase of fillet thickness in the caudal area and raw meat hardness compared with both normal and the white striping abnormality, for which there was no difference. Overall, the occurrence of the individual and combined white striping and wooden breast abnormalities resulted in substantial reduction in the quality of breast meat, although these abnormalities are associated with distinct characteristics. Wooden breast fillets showed lower marinade uptake and higher cooking losses than white-striped fillets for both unprocessed and marinated meats. On the other hand, white-striped fillets showed a moderate decline in marinade and cooking yield. Fillets affected by both abnormalities had the highest (P<0.001) ultimate pH values. In contrast, the effects on colour of raw and cooked meat, drip loss, purge loss and cooked meat shear force were negligible or relatively low and of little practical importance. Thus, the presence of white striping and wooden breast abnormalities impair not only breast meat appearance but also the quality of both raw and marinated meats mainly by reducing water holding/binding abilities.     

Molecular identification of isolated fungi,microbial and heavy metal contamination of canned meat products sold in Riyadh,Saudi Arabia

Several studies have shown that canned meat products may be contaminated with fungal elements, bacteria and even heavy metals which may occur during the transportation, storage and handling processes. We conducted this study to determine the fungal, microbial and heavy metal contents of canned meats in Saudi Arabia. Of the 13 canned meat samples studied, Aspergillus and Penicillium were found in more than 70% of the total samples. Sequences of Penicillium species isolated from meat samples generated a phylogenetic tree which shows that the studied isolates were clustered in four groups. No bacterial contamination was noted in all of the samples. Nine of the 13 samples had iron concentrations above the permissible limit. All samples had zinc and copper levels below the maximum permissible limit. Four samples had cadmium levels above the maximum permissible level. All samples had levels of lead above the maximum permissible levels. These results indicate that fungal elements and higher levels of heavy metals such as lead and cadmium can be found in canned meat products. This may pose as a real danger to consumers, since canned meat products are readily accessible and convenient in Saudi Arabia.     

Maternal and direct dietary polyphenol supplementation affect growth,carcass and meat quality of sheep and goats

The beneficial effects of polyphenol intake such as improved nitrogen retention make them interesting feed supplements for ruminants. In contrast, dietary polyphenols may have adverse effects on the bioavailability of nutrients and palatability of the feed which might impair growth performance. The beneficial and adverse effects might differ between different ruminant species as well as between direct intake and intake of polyphenol metabolites via suckling when supplemented to lactating dams. This study investigated the effects of maternal and direct polyphenol supplementation via grape seed extract in sheep and goats on growth, slaughter performance, meat quality and fatty acid profile. The diet of lactating East Friesian Dairy sheep (n = 11) and Saanen goats (n = 9) and of their lambs (n = 16) and kids (n = 13), respectively, was supplemented either with grape seed extract (dams: 7.4% and offspring: 5.6%, P) or without (C). This resulted in four groups per species, namely maternalC/offspringC, maternalC/offspringP, maternalP/offspringC, and maternalP/offspringP. In lambs but not in goats, maternalP increased average daily gain and improved slaughter performance whereas offspringP had no effect. Maternal and offspring diet did not affect physicochemical meat quality in lambs, but direct intake of grape seed extract increased rancid aroma of burger patties. In goat kids, both maternal and offspring diets slightly affected meat colour. While groups of meat fatty acids (FAs) were not affected by diet in both species, maternalP in lambs as well as maternalP and offspringP in goat kids increased the meat n–6 to n–3 FA ratio compared to the respective control groups. In goat kid but not in lamb meat, direct intake of polyphenols affected the proportions of several rumen biohydrogenation intermediates. In conclusion, grape seed extract can be applied in both the maternal and offspring diets in sheep and goats while maintaining or even improving offspring growth performance and carcass quality. Only few species-specific effects of grape seed extract supplementation were observed, and additive effects were scarce. Larger studies are required to confirm the observed species-specific growth response to maternalP during lactation. The underlying reasons for this differential response need to be further evaluated.     

Effect of sire breed on carcass characteristics and meat and fat quality of heavy pigs reared outdoor and intended for dry-cured meat production

A trial was conducted to study the effect of sire line (Duroc (DU) and Pietrain (PI)) on carcass, meat and fat quality of pigs reared outdoor and destined to dry-cured meat production. No differences between sire genotypes were detected in carcass fat thickness (P > 0.10) but carcasses from DU-sired pigs were longer (P < 0.05) and tended to have a higher yield of trimmed shoulders (P = 0.07) and hams (P = 0.06) than carcasses from PI-sired pigs. Loins from DU-sired genotype showed higher (P < 0.05) L* value and lower (P < 0.01) a* value than loins from PI-sired genotype. Pork from DU-sired offspring tended to have higher (P = 0.09) intramuscular fat (IMF) percentage and lower (P < 0.05) moisture proportion than meat from PI-sired offspring. Also, loins from DU-sired pigs had lower (P < 0.001) thawing losses than loins from PI-sired pigs. The subcutaneous fat from the DU-sired line tended to show lower (P = 0.08) percentage of total polyunsaturated fatty acids (PUFAs) than that from the PI-sire line, mostly due to the higher proportion of C18:2 (P = 0.09) and C20:3 (P < 0.01). However, no effect of crossbreed was detected on the total proportion of saturated, monounsaturated fatty acid (MUFAs) or PUFAs of IMF (P > 0.10). We conclude that both sire lines can be used successfully under outdoor conditions but DU boars are more adequate than PI boars for the production of heavy pigs intended for the dry-cured meat industry.     

The effect of Cu,Zn and Fe chelates on the antioxidative status of thigh meat of broiler chickens

The studies aimed to verify the effect of Cu, Zn and Fe glycine chelate on the antioxidative status in the thigh meat of broiler chickens. The study assumption was that due to the antioxidative or prooxidative effect of Cu, Zn and Fe, these elements supplemented to chickens in an easily assimilable form would modify the antioxidative status of meat and those having a prooxidative effect could deteriorate the quality of meat. The experiment involved three hundred and fifty Ross 308 chickens divided into seven equipotent experimental groups. Over 42 days of the experiment, the chickens were administered Cu, Zn and Fe glycine chelates in an amount corresponding to 50% of the requirement (experimental factor I) or 25% of the requirement (experimental factor II). The level of oxidative stress indicators such as superoxide dismutase, catalase, glutathione, glutathione peroxidase and malondialdehyde was determined in the muscles and blood. The groups receiving Zn or Cu chelate showed statistically confirmed higher activity of superoxide dismutase, catalase, and a higher level of glutathione in comparison to the group receiving Fe chelate. In order to increase the antioxidative stability of thigh meat, it is sufficient that broiler chickens receive Zn or Cu in the form of glycine chelate in an amount covering 25% of their requirement of such minerals. On the other hand, the use of Fe glycine chelates decreased antioxidative stability due to an increase in the level of malondialdehyde, so it should be considered whether the administration of pro-oxidative Fe chelate to broilers is advisable.     

Prevalence of Clostridium difficile in raw cow,sheep, and goat meat in Jazan,Saudi Arabia

Background:Clostridium difficile has been shown to be a nosocomial infection associated with diarrhoea and pseudomembranous colitis in hospitalized patients especially old patients. In my previous studies, it was shown the occurrence of C. difficile in animals feces and vegetables which may act as a source of infection to humans.The aim of the study was to determine the prevalence of C. difficile in retail raw cow, sheep, and goat, meat in Jazan, Saudi Arabia.Method: A total of 600 raw meat samples from cow, sheep, and goat were collected during June–December 2015, and tested for the presence of C. difficile. The method used to check for the presence of C. difficile was by choosing selective enrichment media in C. difficile broth, followed by alcohol shock-treatment and plating onto C. difficile selective medium. C. difficile isolates were typed using PCR ribotyping and also analyzed for antibiotic susceptibility.Results: It was shown that, 9 of 600 meat samples (1.5%) were contaminated with C. difficile. The prevalence of C. difficile was as follow: 7 out of 600 (1.17%) were found in cow, 2 out of 600 (0.3%) were found in sheep, while was no C. difficile was isolated from goat. Eleven out of 18 C. difficile isolates were positive for tcdA, tcdB and cdtB toxin genes and were classified as ribotype 078. Three strains were positive tcdA, and tcdB, and two strains possessed only tcdB. C. difficile strains showed high resistance to ampicillin, gentamycin, erythromycin and nalidixic acid.Conclusions: The present work shows the potential risk of raw meet in transmitting C. difficile to humans.     

Sex effect on meat quality and carcass traits of foals slaughtered at 15 months of age

The effect of sex on carcass measurement, physico-chemical properties, nutritional value and sensory characteristics of foal meat slaughtered at 15 months was investigated. Twelve foals (six females and six males) from an extensive production system in freedom regimen were used for this study. Sex had no statistical influence on carcass measurements, chemical composition, colour parameters, textural properties, amino acid content and sensory characteristics. In contrast, there was a clear effect on the fatty acid profile of longissimus dorsi. Slaughter weight was not significantly (P > 0.05) different between sexes, although higher values were observed in male group compared with female group (194 v. 184 kg). As a consequence, this trend affected carcass weight being slightly (P > 0.05) heavier in the male group than in the female group. On the other hand, cooking loss samples from males showed significantly higher values than those from females (21.50% v. 14.96%, P < 0.05). From a nutritional point of view, the n-6/n-3 ratio in both sexes was within the recommended range for the human diet and this ratio was ostensibly different between the sexes (1.83 v. 1.36, P < 0.05, for male and female, respectively) and it showed a strong correlation (r = −0.91, P < 0.01) with C18:3n-3 content.     

Association of halothane sensitivity with growth and meat quality in pigs

Previous reports have indicated that a proportion of pigs, homozygous normal for the skeletal muscle ryanodine receptor gene (RYR1), was halothane sensitive, and this was associated with poor meat quality when pigs were handled aggressively. This study was conducted to evaluate halothane sensitivity in RYR1-normal pigs, managed under simulated commercial conditions, to ascertain the association of halothane sensitivity with growth rate and meat quality. A total of 363 pigs across four farrowing groups, from seven Landrace sires and 38 Yorkshire–Landrace F1 dams, were tested at 8 weeks of age for halothane sensitivity using a closed system that delivered 5% halothane at 2 l/min for 3 (group 1) or 2 (groups 2 to 4) min. After 1 min, limb rigidity, limb tremors and abdominal discoloration were evaluated on a binomial scale with 0 indicating no reaction and 1 indicating reaction. Testing was repeated 2 days later. At 10 weeks of age, pigs were moved to finishing pens and not moved again until marketing. Within farrowing group, pigs were harvested in one of two groups, and at marketing were moved a distance of 91 m, weighed, tattooed, loaded and transported a distance of 550 km to a commercial harvest plant. After overnight rest, pigs were harvested and the pH of the loin muscle was measured at 45 min (pH45) after stunning. After an 18-h chill, loin muscle pH (pHu), International Commission on Illumination (CIE) L*, a*, b*, color (1 to 6) and marbling (1 to 10) scores and fluid loss percent were collected. Generalized linear mixed models were used to estimate repeatabilities for response to halothane challenge. Repeatabilities for limb rigidity for the front right and left legs were 0.24 and 0.31, respectively, whereas rear right and left leg repeatabilities were 0.19 and 0.17, respectively. Repeatabilities for front right and left leg tremors were 0.16 and 0.20, respectively. Growth rate was not influenced by any measure of halothane sensitivity. Carcasses from pigs exhibiting limb rigidity tended to have lower pH45 (5.88 v. 5.97; P = 0.06), similar pHu (5.47 v. 5.49; P = 0.32), less pH decline from 45 min to 18 h (−0.40 v. −0.50; P = 0.04) and a tendency for greater fluid loss percent (5.01 v. 4.55; P = 0.08) than carcasses from pigs that did not exhibit limb rigidity during halothane challenge. A proportion of pigs normal for RYR1 did exhibit limb rigidity during halothane gas challenge, and subsequently tended to have lower 45 min pH and greater longissimus muscle fluid loss post harvest.     

The Impact of Addition Oats (Avena sativa) and Cinnamon on Cookies and their Biological Effects on Rats Treated with Cirrhosis by CCL4

Oats are represented an important source for nutrition, and it have attracted a lot of attention in recent years. In this study we produced oatmeal cookies and oats was added to formula wheat by 50% and 75%. Also, we added cinnamon to treatments 3 and 4 by 5% to increase nutrition value of oatmeal cookies, improvement sensory evaluation and increase antioxidant properties. All the cookies treatments were storage at room temperature. The purposes of this study were to study antioxidant activity for oats and cinnamon. Also determined the chemical composition include (moisture content, protein, ash, total lipids, crude fibers, carbohydrates and total calories) for oats, white flour and oatmeal cookies treatments. In addition evaluated all of sensory evaluation contain (appearance, color, texture, taste and odor) and microbiological evaluation such as (total bacterial count, spore forming bacteria and mold and yeasts count) for oatmeal cookies treatments. Also, biological assays were preformed to measure level of GPT, GOT, urea, creatinine, total cholesterol, triglycerides, HDL, LDL, and glucose. Furthermore, histopathological examination of both liver and kidneys was analyzed. The obtained results were clarified that the antioxidant activity for oats and cinnamon were 52.91% and 87.91%. Moreover, addition of oats and cinnamon to the cookies improve sensory evaluation as made it more acceptable, decreasing microbial load principally treatments 4 (prepared by 75% oats + 5% cinnamon). Biochemical assays were improved in rats with cirrhosis of carbon tetrachloride and their histopathological examination of liver and kidneys. It was clear that the additions ground whole grain oats and cinnamon to wheat flour based cookies improve its nutritional, chemical, and biological functions properties.     

应用乳酸菌生物保护剂控制肉制品中单增李斯特菌的研究进展

肉制品营养丰富,极易被微生物污染,单增李斯特菌是污染肉制品主要病原菌之一。乳酸菌做为生物保护剂已经被广泛应用于食品中控制单增李斯特菌。本文首先分析了我国肉制品中单增李斯特菌的污染状况,总结了乳酸菌应用于肉制品安全控制的概况;然后进一步详细介绍了乳酸菌对单增李斯特菌的抑菌机理,着重探讨了乳酸菌对单增李斯特菌致病能力(生长、抗性和毒性)的影响;文章最后指出了乳酸菌在食品应用中存在的问题,并对未来的研究方向提供了建议,以期为乳酸菌在食品安全控制中的应用提供参考。     

Effect of age and gender on carcass traits and meat quality of farmed brown hares

A total of 48 sub-adult hares and adult reproducing farmed hares were used to characterize carcass and meat traits according to the age and gender of animals. With respect to carcass traits, when age increased, the carcass weight significantly increased (2022 to 3391 g; P<0.001), but dressing out percentages did not change. The dissectible fat (1.3% to 2.2%; P<0.05) and Longissimus lumborum (LL) proportions (13.5% to 14.5%; P<0.001) and muscle-to-bone ratio of hind legs (5.11 to 6.23; P<0.001) increased, whereas the hind leg proportions decreased (37.3% to 36.3%; P=0.01). As for the meat quality, the pH of hind leg (5.74 to 5.83; P<0.001) and LL (5.53 to 5.69; P<0.001) increased with age, while the L* index decreased in both cuts (42.9 to 34.4 in hind leg; 45.1 to 40.3 in LL; P<0.001). The redness index increased at the hind leg (4.07 to 5.76; P<0.001), while it decreased at LL (3.03 to 1.46; P<0.001). In the case of the hind leg, meat thawing losses decreased (1.58% to 1.02%), and shear force increased (2.97 to 4.02 kg/g). In the case of LL, thawing losses decreased (8.79% to 4.91%; P<0.001) in the adult hares compared with the sub-adult ones. Meat water and protein contents decreased in the hind leg and LL of the adult hares compared with the sub-adult ones, whereas ether extract increased in a restricted range in LL only (0.92% to 1.11%; P<0.001). In the case of the hind leg, the rate of the saturated fatty acids (SFA) decreased (41.0% to 26.7%), and the rate of the polyunsaturated fatty acids (PUFA) increased (34.0% to 45.3%) (P<0.001). In the case of LL, SFA (38.6% to 42.9%) and monounsaturated fatty acids (19.4% to 27.2%) increased, whereas PUFA decreased (42.0% to 30.1%) when the age increased (P<0.001). Gender affected only the slaughter results and carcass traits. In conclusion, farmed hares have favourable slaughter results (high dressing percentage), carcass traits (high hind legs and loins rates), and meat nutritional value (high-protein, low-fat meat). This fact would offer additional commercial opportunities, in addition to restocking, to hare farmers.     

Simultaneous detection of Carnobacterium and Leuconostoc in meat products by multiplex PCR

AIMS: To develop a multiplex PCR approach for simultaneous detection of Leuconostoc and Carnobacterium and its validation in meat products. METHODS AND RESULTS: Two multiplex PCR assays were developed using newly designed 16S rDNA-directed primers adapted to the current taxonomic situation of genera Leuconostoc and Carnobacterium that allow: (i) simultaneous detection of both genera, and members of the nonmotile species of genus Carnobacterium and (ii) identification in a single assay of the nonmotile species C. divergens, C. maltaromicum and C. gallinarum. Sensitivity values of 10(3) and 10(4) CFU g(-1) were determined for multiplex PCR detection of Carnobacterium and Leuconostoc, respectively, following artificially inoculated meat trials. In addition, both multiplex PCR assays were validated in 14 naturally contaminated samples covering nine types of meat products. Results obtained by colony identification were confirmed by PCR detection. CONCLUSIONS: The methods described in this study provide a rapid and reliable tool for PCR detection of Carnobacterium and Leuconostoc, in meat products, and for colony identification. SIGNIFICANCE AND IMPACT OF THE STUDY: This multiplex PCR approach will help in the analysis of the spoilage microbiota of refrigerated vacuum-packaged meat product in order to determine the appropriate preservation method.     

The relationship of pork longissimus muscle pH to mitochondrial respiratory activities,meat quality and muscle structure

The way the pH falls post-slaughter has an impact on meat quality. Pork longissimus muscles (n=48) were sorted in fast- (FG) (n=15) and normal glycolysing (NG) (n=33) muscles according to the post-slaughter pH 45 min values (FG<6.0; NG>6.0). FG muscles (5.84±0.04) compared with NG muscles (6.27±0.04) were accompanied with higher temperature, electrical conductivity, lightness and yellowness, and reduced grill loss and shear force values (P<0.05), but there were no pH-dependent changes of the drip loss and redness results. FG muscles had higher (P<0.05) percentages of fast-twitch glycolytic and lower proportions of fast-twitch oxidative and slow-twitch oxidative (P<0.05) muscle fibres. The study confirms the relationship of pH value to meat quality and muscle fibre characteristics also showing that pH values have no impact on intrinsic mitochondrial respiratory function.     

Malic enzyme 1 genotype is associated with backfat thickness and meat quality traits in pigs

Malic enzyme 1 (ME1) is a part of the tricarboxylate shuttle that provides NADPH and acetyl-CoA required in fatty acid biosynthesis. The pig ME1 locus maps on the proximal end of chromosome 1, where a quantitative trait loci (QTL) affecting fat deposition has been previously described. We amplified fragments of 1457 and 1459 bp that corresponded to the complete coding region and the 3'-untranslated region (UTR), respectively, of the pig ME1 gene. The sequences of these two fragments in pigs from three breeds (Landrace, Large White and Piétrain) contained five single nucleotide polymorphisms (SNP) in the 3'-UTR: C1706T, G1762T, A1807C, C1857A and T1880A. Three haplotypes were found in two generations of a selected Landrace population: H1 (C1706 G1762 A1807 C1857 A1880), H2 (C1706 G1762 A1807 C1857 T1880) and H3 (T1706 T1762 C1807 A1857 T1880). Using Bayesian association analyses, significant associations (highest posterior density at 95%) between ME1 genotype and backfat (BF) thickness at 171 days and muscular pH were found in a Landrace population.     

Dried artichoke bracts in rabbits nutrition: effects on the carcass characteristics,meat quality and fatty-acid composition

In this study, the effects of the inclusion of artichoke bracts (AB) in rabbit diets on the carcass characteristics and rabbit meat quality were studied. A total of 120 rabbits aged 38 days were used and divided into three groups that were fed with different isonitrogenous and isocaloric diets supplemented with AB at 0%, 5% and 10%. The animals were single housed in wire cages at a temperature of 22±2°C and had free access to clean drinking water. At 96 days of age, 12 rabbits/group were slaughtered in an experimental slaughterhouse without fasting. The carcass was weighed and the weights of the skin and full gastrointestinal tract were recorded. Carcasses were chilled at +4°C for 24 h in a refrigerated room. The chilled carcass weight (CCW), dressing out percentage (CCW as percentage of slaughter weight), and the ratio of the head and liver were determined as a percentage of CCW. The reference carcass weight was also calculated. Carcasses were halved and the two longissimus dorsi (LD) muscles were excised. The left LD muscle was divided into two parts. The fore part was used to measure pH, colour and cooking losses. The hind part of the left LD was vacuum-packed, frozen at –20°C and then freeze-dried. Proximate composition, fatty-acid profile and thiobarbituric acid-reactive substances values were determined on freeze-dried samples. Results showed that carcass characteristics, LD muscle traits and its oxidative status were not affected by the AB supplementation, except for the meat ether extract content that increased from 0.68% to 0.94% on fresh matter basis with the increase of the AB supplementation (P<0.01). The α-linolenic acid proportion decreased with the increase of the AB supplementation from 3.58% to 2.59% in the LD muscle and from 4.74% to 3.62% in the perirenal fat, whereas the n-6/n-3 ratio increased significantly with increasing AB inclusion from 7.15 to 10.20 in the LD muscle and from 6.68 to 9.35 in the perirenal fat (P<0.01). Furthermore, no significant difference was found in preference among meat samples from each group. The enrichment of the rabbit’s diet with AB allows the production of rabbit meat with a good degree of unsaturation and low saturation, even if the n-6/n-3 ratio was slightly worse.     

In vitro and in situ growth characteristics and behaviour of spoilage organisms associated with anaerobically stored cooked meat products

AIMS: Understanding spoilage caused by different types of spoilage organisms, associated with vacuum-packaged sliced cooked meat products (CMP). METHODS AND RESULTS: First, strains were characterized in a broth at 7 degrees C under anaerobic conditions to compare their growth rate, acidifying character and metabolite production under conditions simulating refrigerated vacuum-packaged conditions. Brochotrix thermosphacta grew faster than the lactic acid bacteria (LAB). Within the group of the LAB, all strains grew fast except Leuconostoc mesenteroides subsp. dextranicum and Leuconostoc carnosum. Secondly, the organisms were inoculated on a model cooked ham to better understand the relationship between spoilage, microbial growth, pH, metabolite production and accompanying sensory changes. Most rapidly growing strains were Leuc. mesenteroides subsp. mesenteroides followed by B. thermosphacta, while Leuc. mesenteroides subsp. dextranicum and Leuc. carnosum grew very slowly compared with the other LAB. Brochotrix thermosphacta caused sensory deviations at a lower cell number compared with the LAB. The related pH changes, metabolite production and sensory perception are presented. CONCLUSIONS: In this pure culture study, B. thermosphacta and Leuc. mesenteroides subsp. mesenteroides had the highest potential to cause rapid spoilage on CMP. SIGNIFICANCE AND IMPACT OF THE STUDY: A systematic study on the behaviour of spoilage organisms on a model cooked ham to establish the relationship between microbial growth, pH, metabolite formation and organoleptic deviations.