The association between herd characteristics and salmonella prevalence in slaughter age pigs

Many factors have the potential to result in exposure of pigs to Salmonella and/or to increase the potential shedding at the time of slaughter. Observation of selected production systems has suggested that control of Salmonella may not occur using common disease management strategies, such as batch pig flow, as do many other diseases.\u27 A rational approach to Salmonella reduction would be to rank risk factors, to aid in selecting. We designed this study to assess risk factors of Salmonella status at slaughter

The association of antimicrobial resistance patterns and reported usage of antimicrobials in commercial growing pig production

The relationship between into microbial use and the development of resistance to antimicrobials has been demonstrated through both external models and has been observed clinically. However, the strength of this relationship in practical production systems has not been clearly quantified. We designed this study to examine the strength of the relationship between use of antimicrobials and the occurrence of antimicrobial resistence among Salmonella spp. collected from the same groups of growing pig

Pork producers attitudes, knowledge and production practices that relate to on farm HACCP development

For the HACCP approach to be the basis of pathogen reduction on farms, pork producers will need knowledge about the pathogens and the methods for their control. In the United States, there are no recent broadly based reports in the scientific literature on the knowledge, attitude and opinions of pork producers regarding pork food safety. Several major U.S. production systems have adopted onfarm production practices uniquely designed for their company operations and which are standardized farm-tofarm. However, much of swine production within the U.S. involves independent pork producers interfacing with independent packers. With the introduction of packing plant HACCP plans, the expectation of the packer/processor has of the producer\u27s role in food safety and quality assurance is changing. Producers have a need to understand the HACCP system and the role they have in the pork production chain

Antimicrobial resistance patterns of Salmonella isolates collected from slaughter age pigs

Salmonellae are ubiquitous in nature and are recovered from many animal species including swine. However, prevalence of specific serotypes can vary. Although carriage is often observed, fecal shedding can be sporadic (2). Salmonella, as well as other food borne pathogens, can be transferred from animals to the human population. However, since the federally mandated HACCP program has been implemented, a reduction in Salmonella among the major food animals has been observed

The effect of buffered peptone water pre-enrichment on detected prevalence of Salmonella in swine feces

Sensitive and specific detection methods are important to understand the epidemiology of Salmonella and to develop appropriate control strategies. The risk of Salmonella contamination of pork is associated with subclinical Salmonella infections in pigs. In most epidemiological investigations, microbiological culture has been used to deterimine Salmonella infection status for infections on swine farms or at slaughter plants. However, identification of Salmonella by culture among subclinically infected pigs may be highly influenced by the intermittent shedding status of pigs. The types and volume of samples used for culture as well as culture protocol used in microbiological examination can influence the sensitivity of the method

Reservoirs of Salmonella infection on swine farms in lllinois

An ecological study was conducted to identify possible reservoirs of Salmonella on swine farms in Dlinois. In 1998, 6 single-site farrow-to-finish swine farms with at least 100 sows, identified previously at slaughter as having a high prevalence of Salmonella infection, were selected for study. Between March and October 1998, each farm was visited 4 times. On each visit, 60- 150 pigs were sampled, from various age groups (pre-weaning pigs, nursery, grower, finisher, sows). Overnight trapping was conducted to collect rodents, cats, and arthropods. Fecal samples were obtained from pigs, rodents and cats. Environmental samples of water, feed, boots and pen floor material were also obtained. Samples were cultured for Salmonella using tetrathionate broth, followed by Rappaport\u27s medium for enrichment. Salmonella was detected in every reservoir for which at least 20 samples were available. Salmonella was detected in the feces of sows and finishing pigs on each farm, and in pen floor samples on 5 of the 6 farms. The overall prevalence of Salmonella in swine fecal samples was 2.8%; the prevalence of Salmonella shedding by pigs increased with increasing age (1.4% in suckling pigs, 3.5% in near market weight finishing pigs, 6.2% in sows). Boot samples had the highest prevalence of infection (17% ), suggesting a likely mode of transntission; on one farm, 81% of boot samples were positive. The prevalence of infection also was relatively high in cats (14%), ntice (10%), and flies (7%). The overall prevalence of Salmonella in floor samples was 7%, with one farm having 20% of floor samples positive, thereby implicating pen floors as a source for transntission. Feed samples had a low prevalence of salmonella (2%), suggesting that feed played a lesser role in Salmonella transntission

Spatial and temporal patterns of the distribution of Salmonella on swine farms in Illinois

An ecological study was conducted to identify possible reservoirs of Sa/monelln. From March to November 1998 there were 4 visits to each of 6 selected swine farms in lllinois. Fecal samples were collected from swine in longitudinal and cross-sectional groups on each visit to each farm. Fecal samples were also collected from chickens, cattle, cats, dogs, rodents, and other wildlife. Overnight trapping and hand capture techniques were used to obtain samples from wildlife, cats, and arthropods. Environmental samples including feed, water, pen floor material, bootdebris, and bird feces were collected. All samples were evaluated as Salmonel/n positive or negative by culture. A total of 3564 samples representing 40 sample types were collected and cultured. Of 2442 swine fecal samples, 935 were from longitudinal cohorts, and 1507 were from cross sectional groups. Non-swine fecal samples and environmental samples comprised the remaining 1123 samples. Salmonella was cultured from 157 samples in 19 different sample types. All positive samples are mapped with representation of location and time of collection on the farm

An estimate of Salmonella prevalence on Illinois swine farms using mesenteric lymph node cultures

Accurate description of Salmonella prevalence is an important step toward understanding the epidemiology of the organism. A U.S. national prevalence estimate of fecal prevalence of Salmonella species showed that the organisms were commonly detected on farms. with 58 of 160 farms (38.2%) with one or more positive sample. The same survey, however, suggested that the prevalence rate differed by geographic region, with the southeastern area of the country having more than double the prevalence of the Midwest

Salmonella prevalence in market weight pigs before and after shipment to slaughter

Samples commonly used for microbiological culture of subclinical Salmonella infection in market weight pigs include fecal material, mesenteric lymph nodes, cecal contents, rectal contents, and rectal swabs. In epidemiologic investigations, collection of abanoir samples offers certain advantages over farm collected samples. Sampling at slaughter offers the advantage of a wider range of sample types. For practical reasons, samples collected on the farm for microbiological culture are usually limited to fecal samples, whereas slaughter samples can include lymph node and higher gut contents. The ease of collection at the slaughter plant facilitates sampling a large number of herds. Detection of Salmonella in slaughtered pigs is also a useful indicator of risk to pork safety, because slaughter processing is the primary point where direct risk of entry into the food chain exists. However, it is possible that pigs may become infected during transportation and lairage. Further, it is possible that pigs harbor Salmonella while on the farm, but they do not shed the organism into feces. The stress of events iromediately pre-slaughter may then induce these non-shedding infected pigs to begin shedding

Catalytic enantioselective syn hydration of enones in water using a DNA-based catalyst

The enantioselective addition of water to olefins in an aqueous environment is a common transformation in biological systems, but was beyond the ability of synthetic chemists. Here, we present the first examples of a non-enzymatic catalytic enantioselective hydration of enones, for which we used a catalyst that comprises a copper complex, based on an achiral ligand, non-covalently bound to (deoxy)ribonucleic acid, which is the only source of chirality present under the reaction conditions. The chiral β-hydroxy ketone product was obtained in up to 82% enantiomeric excess. Deuterium-labelling studies demonstrated that the reaction is diastereospecific, with only the syn hydration product formed. So far, this diastereospecific and enantioselective reaction had no equivalent in conventional homogeneous catalysis