Molecular characterization of five porcine candidate genes for drip loss in pork

Drip loss is the loss of fluid from a piece of meat without mechanical force and represents an important meat quality trait. Previous work revealed a quantitative trait locus (QTL) for drip loss in pork in an experimental Duroc x Pietrain (DUPI) F2 family on SSC 5. Based on functional data indicating their possible involvement in water holding capacity and their expression in skeletal muscle, we selected five positional candidates (ACO2, ADSL, CBY1, KCNJ4, PLA2AG6) out of 130 predicted genes in the QTL interval for further analysis. We performed a mutation analysis of all coding exons and discovered 204 polymorphisms. We genotyped 39 single nucleotide polymorphisms (SNPs) in 192 Pietrain pigs with extreme drip loss phenotypes and detected a possible association with drip loss for one non-coding SNP in the ADSL gene (ss107793818, p(raw) = 0.021). Correspondingly, ADSL diplotypes were associated with drip loss and pH1 of M. longissimus dorsi. However, after correction for multiple testing, none of the tested SNPs were significantly associated with drip loss. One possible explanation for these results is that one of the QTL-alleles from the experimental DUPI family may be fixed or nearly fixed in the tested Pietrain population.

Food-safety hazards in the pork chain in Nagaland, North East India: implications for human health.

Pork occupies an important place in the diet of the population of Nagaland, one of the North East Indian states. We carried out a pilot study along the pork meat production chain, from live animal to end consumer. The goal was to obtain information about the presence of selected food borne hazards in pork in order to assess the risk deriving from these hazards to the health of the local consumers and make recommendations for improving food safety. A secondary objective was to evaluate the utility of risk-based approaches to food safety in an informal food system. We investigated samples from pigs and pork sourced at slaughter in urban and rural environments, and at retail, to assess a selection of food-borne hazards. In addition, consumer exposure was characterized using information about hygiene and practices related to handling and preparing pork. A qualitative hazard characterization, exposure assessment and hazard characterization for three representative hazards or hazard proxies, namely Enterobacteriaceae, T. solium cysticercosis and antibiotic residues, is presented. Several important potential food-borne pathogens are reported for the first time including Listeria spp. and Brucella suis. This descriptive pilot study is the first risk-based assessment of food safety in Nagaland. We also characterise possible interventions to be addressed by policy makers, and supply data to inform future risk assessments.

Radiological stab wound channel depiction with instillation of contrast medium

The radiological depiction of stab wounds in soft-tissues using multislice computed tomography is difficult and the hereby obtained images often lack contrast. To overcome these shortcomings we tried a new method. We gently instilled the contrast medium Lipiodol((R)) Ultra-fluide into five experimentally induced stab wounds on a pork haunch. Subsequent MSCT reconstructions of the wounds delivered clear, for medical laymen easily appreciable images regarding the stab direction and the stab depth. We believe that this easy and rapid technique can be useful in the examination of stab wounds in living and dead victims of sharp trauma.

A study to demonstrate freedom of Trichinella spp. in domestic pigs in Switzerland

Trichinellosis is a food-borne zoonotic disease caused by the nematode Trichinella spp. Many omnivorous and carnivorous animal species can act as host for this parasite, including domestic pigs. To protect public health, it should be ensured that pork should not contain infective Trichinella larvae. Surveillance for Trichinella spp. can be done using direct (larval detection) and indirect (antibody detection) diagnostic techniques. The aim of this study was to demonstrate the absence of infection in Swiss domestic pigs. An ELISA was used as the initial screening test, and sera reacting in ELISA were further investigated using both a Western blot for serology and an artificial digestion test with 20 g of diaphragm tissue for larval detection. A total of 7412 adult pigs, 9973 finishing pigs and 2779 free-ranging pigs were tested. Samples from 17 (0.23%) adult pigs, 16 (0.16%) finishing pigs and nine (0.32%) free-ranging pigs were ELISA-positive, but all of these sera were subsequently negative by Western blot and by the artificial digestion method. Based on these findings, an absence of Trichinella infections in adult pigs (target prevalence 0.04%) and finishing pigs (target prevalence 0.03%) can be concluded. The results also demonstrated that the prevalence of Trichinella infections does not exceed 0.11% in free-ranging pigs, the group with the highest risk of exposure.

[Methods for investigating Trichinella infections in domestic and wild animals]

Trichinellosis is an important parasitic zoonosis that is caused by the intracellular nematode Trichinella spp.. Infection of humans occurs through consumption of raw (or undercooked) meat containing infectious larvae. In Europe, meat from pork, horse, and wild boar have been identified as most important sources of Trichinella infections in humans. In Switzerland, both the domestic pig and wild boar population are considered free of Trichinella. Conversely, Swiss foxes, lynxs and recently a wolf were found to be infected, the species identified in these animals was always referred to as Trichinella britovi. Although this species rarely infects pork and, compared to Trichinella spiralis, only causes reduced pathogenic effects in humans, the basic presence of Trichinella in Switzerland cannot be neglegted. This fact has gained increasing importance since the responsible authorities in the European Union (EU) are preparing regulations for the official Trichinella-control in meat in order to improve food safety for consumers. These regulations will be implemented as a consequence of the recent association of east European countries with the EU. This new legislation particularly takes into account, that in the past by far most cases of human trichinellosis in the EU were due to consumption of imported east European meat.Within the framework of the bilateral agreements of Switzerland with the EU, the Swiss veterinary public health authorities will have to comply with the foreseen EU regulations. Although diagnostic methods for the direct demonstation of Trichinella in pork meat are already routine practice in several Swiss abattoirs, the implementation of a meat control program for Trichinella for the entire slaughter pig population of the country would lead to an enormous increase in costs for the administration and will require an increased infrastructure in veterinary services. In order to find a reduced testing format for monitoring Trichinella infections in Swiss pork, an infection risk-oriented survey strategy is currently evaluated. In the present article, this minimized survey strategy is discussed regarding its compatibility with the EU regulations laying down rules for the official control of meat for Trichinella.

Risk scoring for setting priorities in a monitoring of antimicrobial resistance in meat and meat products

Meat and meat products can be contaminated with different species of bacteria resistant to various antimicrobials. The human health risk of a type of meat or meat product carry by emerging antimicrobial resistance depends on (i) the prevalence of contamination with resistant bacteria, (ii) the human health consequences of an infection with a specific bacterium resistant to a specific antimicrobial and (iii) the consumption volume of a specific product. The objective of this study was to compare the risk for consumers arising from their exposure to antibiotic resistant bacteria from meat of four different types (chicken, pork, beef and veal), distributed in four different product categories (fresh meat, frozen meat, dried raw meat products and heat-treated meat products). A semi-quantitative risk assessment model, evaluating each food chain step, was built in order to get an estimated score for the prevalence of Campylobacter spp., Enterococcus spp. and Escherichia coli in each product category. To assess human health impact, nine combinations of bacterial species and antimicrobial agents were considered based on a published risk profile. The combination of the prevalence at retail, the human health impact and the amount of meat or product consumed, provided the relative proportion of total risk attributed to each category of product, resulting in a high, medium or low human health risk. According to the results of the model, chicken (mostly fresh and frozen meat) contributed 6.7% of the overall risk in the highest category and pork (mostly fresh meat and dried raw meat products) contributed 4.0%. The contribution of beef and veal was of 0.4% and 0.1% respectively. The results were tested and discussed for single parameter changes of the model. This risk assessment was a useful tool for targeting antimicrobial resistance monitoring to those meat product categories where the expected risk for public health was greater.

A genome-wide association study to detect QTL for commercially important traits in Swiss Large White boars

The improvement of meat quality and production traits has high priority in the pork industry. Many of these traits show a low to moderate heritability and are difficult and expensive to measure. Their improvement by targeted breeding programs is challenging and requires knowledge of the genetic and molecular background. For this study we genotyped 192 artificial insemination boars of a commercial line derived from the Swiss Large White breed using the PorcineSNP60 BeadChip with 62,163 evenly spaced SNPs across the pig genome. We obtained 26 estimated breeding values (EBVs) for various traits including exterior, meat quality, reproduction, and production. The subsequent genome-wide association analysis allowed us to identify four QTL with suggestive significance for three of these traits (p-values ranging from 4.99×10⁻⁶ to 2.73×10⁻⁵). Single QTL for the EBVs pH one hour post mortem (pH1) and carcass length were on pig chromosome (SSC) 14 and SSC 2, respectively. Two QTL for the EBV rear view hind legs were on SSC 10 and SSC 16.

Campylobacter spp., Yersinia enterocolitica, and Salmonella enterica and their simultaneous occurrence in German fattening pig herds and their environment.

Campylobacter spp., Salmonella enterica, and Yersinia enterocolitica are common causes of foodborne infections in humans with pork as a potential source. Monitoring programs at farm level are, to date, only implemented for S. enterica, while epidemiological knowledge of the other two pathogens is still lacking. This study aimed to assess the pathogen load (in the pigs' environment) in fattening pig herds, their simultaneous occurrence, and the occurrence of Campylobacter spp. and Y. enterocolitica in herds in different Salmonella risk categories. In 50 fattening pig herds in northern Germany, four pooled fecal samples and 10 swab samples from the pigs' direct environment (pen walls, nipple drinkers), indirect environment (hallways, drive boards), and flies and rodent droppings were collected from each herd and submitted for cultural examination. Campylobacter spp. were detected in 38.1% of fecal, 32.7% of direct environment, 5.3% of indirect environment, and 4.6% of flies/pests samples collected, and Y. enterocolitica in 17.1, 8.1, 1.2, and 3.1% and S. enterica in 11.2, 7.7, 4.1, and 1.5%, respectively. For Campylobacter spp., Y. enterocolitica, and S. enterica, 80, 48, and 32% of herds were positive, respectively; 22 herds were positive for both Campylobacter spp. and Y. enterocolitica, 12 for Campylobacter spp. and S. enterica, and 7 for Y. enterocolitica and S. enterica. There was no significant association between the pathogens at herd level. Campylobacter spp. and Y. enterocolitica were found more often in samples from the low Salmonella risk category (odds ratio, 0.51; confidence interval, 0.36 to 0.73, and 0.3, 0.17 to 0.57), and this was also the case for Y. enterocolitica at herd level (odds ratio, 0.08; confidence interval, 0.02 to 0.3). This study provides evidence that the pigs' environment should be accounted for when implementing control measures on farms against Campylobacter spp. and Y. enterocolitica. An extrapolation from the current Salmonella monitoring to the other two pathogens does not seem feasible.

Occurrence and Genetic Characteristics of Third-Generation Cephalosporin-Resistant Escherichia coli in Swiss Retail Meat

Prevalence and genetic relatedness were determined for third-generation cephalosporin-resistant Escherichia coli (3GC-R-Ec) detected in Swiss beef, veal, pork, and poultry retail meat. Samples from meat-packing plants (MPPs) processing 70% of the slaughtered animals in Switzerland were purchased at different intervals between April and June 2013 and analyzed. Sixty-nine 3GC-R-Ec isolates were obtained and characterized by microarray, PCR/DNA sequencing, Multi Locus Sequence Typing (MLST), and plasmid replicon typing. Plasmids of selected strains were transformed by electroporation into E. coli TOP10 cells and analyzed by plasmid MLST. The prevalence of 3GC-R-Ec was 73.3% in chicken and 2% in beef meat. No 3GC-R-Ec were found in pork and veal. Overall, the blaCTX-M-1 (79.4%), blaCMY-2 (17.6%), blaCMY-4 (1.5%), and blaSHV-12 (1.5%) β-lactamase genes were detected, as well as other genes conferring resistance to chloramphenicol (cmlA1-like), sulfonamides (sul), tetracycline (tet), and trimethoprim (dfrA). The 3GC-R-Ec from chicken meat often harbored virulence genes associated with avian pathogens. Plasmid incompatibility (Inc) groups IncI1, IncFIB, IncFII, and IncB/O were the most frequent. A high rate of clonality (e.g., ST1304, ST38, and ST93) among isolates from the same MPPs suggests that strains persist at the plant and spread to meat at the carcass-processing stage. Additionally, the presence of the blaCTX-M-1 gene on an IncI1 plasmid sequence type 3 (IncI1/pST3) in genetically diverse strains indicates interstrain spread of an epidemic plasmid. The blaCMY-2 and blaCMY-4 genes were located on IncB/O plasmids. This study represents the first comprehensive assessment of 3GC-R-Ec in meat in Switzerland. It demonstrates the need for monitoring contaminants and for the adaptation of the Hazard Analysis and Critical Control Point concept to avoid the spread of multidrug-resistant bacteria through the food chain.

Comparison of stab wound probing versus radiological stab wound channel depiction with contrast medium

BACKGROUND Instillation of contrast medium into stab wounds has shown promising results regarding visibility and assessment of general stab direction with computed tomography. However, the accuracy of this method--and, incidentally also probing of stab wounds--has to our knowledge not previously been examined. Also the effect of bluntness of different stabbing objects on the examination of stab wounds was not considered before this study. METHODS Using a pocket-knife, a steak-knife, and a Phillips screwdriver, nine stab wounds each were inflicted to three pork haunches. The depths of the stab wounds were determined by probing and multislice computed tomography (MSCT) after instillation of a contrast medium (CM) and then compared to those observed by dissection, our internal "gold standard". RESULTS In stab wounds inflicted by knives, MSCT-CM and probing provided results which differed by roughly 10-11% from the dissection results. In screwdriver stabs MSCT-CM showed a deviation of almost 30%, probing over 33%. DISCUSSION MSCT-CM is a possible alternative to layer-by-layer dissection in autopsy cases of knife stab wounds. Probing, although obsolete in post-mortem examinations, is sufficiently accurate in determining the length of a stab wound of a living person. In cases of stab wounds with blunt objects such as screwdrivers, neither MSCT-CM nor probing proved to be sufficiently accurate. CONCLUSION MSCT-CM is a possible alternative to layer-by-layer dissection in autopsy cases of knife stab wounds. Probing, although obsolete in post-mortem examinations, is sufficiently accurate in determining the length of a stab wound of a living person. In cases of stab wounds with blunt objects such as screwdrivers, neither MSCT-CM nor probing proved to be sufficiently accurate.

Exposure assessment of extended-spectrum beta-lactamases/AmpC beta-lactamases-producing Escherichia coli in meat in Denmark

INTRODUCTION Extended-spectrum beta-lactamases (ESBL) and AmpC beta-lactamases (AmpC) are of concern for veterinary and public health because of their ability to cause treatment failure due to antimicrobial resistance in Enterobacteriaceae. The main objective was to assess the relative contribution (RC) of different types of meat to the exposure of consumers to ESBL/AmpC and their potential importance for human infections in Denmark. MATERIAL AND METHODS The prevalence of each genotype of ESBL/AmpC-producing E. coli in imported and nationally produced broiler meat, pork and beef was weighted by the meat consumption patterns. Data originated from the Danish surveillance program for antibiotic use and antibiotic resistance (DANMAP) from 2009 to 2011. DANMAP also provided data about human ESBL/AmpC cases in 2011, which were used to assess a possible genotype overlap. Uncertainty about the occurrence of ESBL/AmpC-producing E. coli in meat was assessed by inspecting beta distributions given the available data of the genotypes in each type of meat. RESULTS AND DISCUSSION Broiler meat represented the largest part (83.8%) of the estimated ESBL/AmpC-contaminated pool of meat compared to pork (12.5%) and beef (3.7%). CMY-2 was the genotype with the highest RC to human exposure (58.3%). However, this genotype is rarely found in human infections in Denmark. CONCLUSION The overlap between ESBL/AmpC genotypes in meat and human E. coli infections was limited. This suggests that meat might constitute a less important source of ESBL/AmpC exposure to humans in Denmark than previously thought - maybe because the use of cephalosporins is restricted in cattle and banned in poultry and pigs. Nonetheless, more detailed surveillance data are required to determine the contribution of meat compared to other sources, such as travelling, pets, water resources, community and hospitals in the pursuit of a full source attribution model.