An assessment of epidemic outbreaks of salmonellosis connected with poultry plant production]

The causes of the simultaneous rise of salmonellosis morbidity induced by S. enteritidis among the population of three towns in the Perm region were studied. The study revealed the leading role of eggs and chicken meat as factors contributing to the transfer of this infection to the population of different territories, commonly supplied with the products of one poultry plant. The contamination of eggs and chickens with S. enteritidis occurred at the plant due to Salmonella infection of chickens, parallel with the use of nonbalanced mixed fodder, originally intended for feeding swine. Analysis of the epidemic and epizootic processes of Salmonella infection in this epidemic situation made it possible to reliably establish the factors contributing to the transfer of the infective agent and the site of contamination.     

The role of the aggregation of microbial cells in the development of salmonellosis in mice

The dependence of the invasive action of Salmonella typhimurium in mice on the aggregation of microbial cells has been studied in vivo, as well as in vitro on explanted intestinal tissue. The aggregation of salmonellae on kaolin grains has been found to lead to an increase in the level of adhesion of salmonellae to the intestinal mucosa of mice in vitro, to the accelerated course of infection in mice and their death and to the increased contamination of the spleen. The data obtained in these experiments age indicative of the possibility of the adverse influence of some sorbents on the course of the infectious process and confirm the concept advanced by the authors on the major importance of the surface concentration of salmonellae on the mucous membrane for the effectiveness of contamination.     

An evaluation of the scope of the circulation of Salmonella among the workers of commercial poultry- and meat-packing enterprises based on serological study data in the PHA test]

Serum samples from 641 workers of large poultry and meat-packing plants were studied in the passive hemagglutination test with the use of Salmonella complex and serogroup diagnostica. A specific increase in the level of anti-Salmonella antibodies in 60.7% of poultry plant workers and in 9.8% of meat-packing plant workers was established. Among the workers of the poultry plants the most pronounced immune shifts were detected in persons having contacts with sick poultry and pathological material and among the employees of the meat-packing plant, in those who ate raw sausage meat. A high level of antibodies in the professional groups under study was observed as early as in the first year of work at the plant and persisted over the whole period of this work. Under the conditions of constant contamination of the workers of poultry and meat-packing plants with small doses of salmonellae specific immunity to this infection was seemingly induced, which inhibited the development of the manifest forms of infection, but did not prevent the formation of chronic carrier state.     

Coconut and Salmonella Infection

Raw, unprocessed coconut supports the growth of salmonellae as well as that of other enteric bacteria, salmonellae being particularly resistant to subsequent desiccation. Original contamination is not due to carriers or to polluted water supplies, but to contact with bacteria-containing soils followed by dispersion via infected coconut milk and shells. Pasteurization of raw coconut meat in a water bath at 80 C for 8 to 10 min effectively killed such bacteria, did not injure the product, and provided a prophylactic method now widely used by the coconut industry.     

Introduction of African Swine Fever into the European Union through Illegal Importation of Pork and Pork Products

Transboundary animal diseases can have very severe socio-economic impacts when introduced into new regions. The history of disease incursions into the European Union suggests that initial outbreaks were often initiated by illegal importation of meat and derived products. The European Union would benefit from decision-support tools to evaluate the risk of disease introduction caused by illegal imports in order to inform its surveillance strategy. However, due to the difficulty in quantifying illegal movements of animal products, very few studies of this type have been conducted. Using African swine fever as an example, this work presents a novel risk assessment framework for disease introduction into the European Union through illegal importation of meat and products. It uses a semi-quantitative approach based on factors that likely influence the likelihood of release of contaminated smuggled meat and products, and subsequent exposure of the susceptible population. The results suggest that the European Union is at non-negligible risk of African swine fever introduction through illegal importation of pork and products. On a relative risk scale with six categories from negligible to very high, five European Union countries were estimated at high (France, Germany, Italy and United Kingdom) or moderate (Spain) risk of African swine fever release, five countries were at high risk of exposure if African swine fever were released (France, Italy, Poland, Romania and Spain) and ten countries had a moderate exposure risk (Austria, Bulgaria, Germany, Greece, Hungary, Latvia, Lithuania, Portugal, Sweden and United Kingdom). The approach presented here and results obtained for African swine fever provide a basis for the enhancement of risk-based surveillance systems and disease prevention programmes in the European Union.     

Microbiological Quality of Protein Feed Supplements Produced by Rendering Plants

Samples of protein feed supplements produced by rendering plants were examined for salmonellae, total aerobic bacterial counts, coliform counts, and enterococci. Isolations of salmonellae were more frequent from products with high counts; however, 6% of the samples with total counts of less than 1,000 per gram and 14% of the samples with coliform counts of less than 1 per gram contained salmonellae. Serotypes of Escherichia coli which have been associated with disease in domestic animals and poultry were also isolated from products. Although the distribution of serotypes of salmonellae isolated from environmental swabs and flies was similar to that isolated from products, the isolation of several serotypes from flies which had not been isolated in plants suggested that flies may be a potential source of contamination.     

Evaluation of the bioavailability of radionuclides from soil in cattle by an in vitro method

Factors have been examined which influence the radionuclides sorption from soil particles by fluid imitating rumen liquid of the cattle. It is noted that the extent of extractability of 137Cs from soil is influenced mainly by presence of potassium ions in modelling liquid. Major factor influencing the release of 90Sr from soil is pH value of the medium. The presence of heavy metals salts affected the release of radionuclides from soil particles. The data observed make it possible to use the modelling solutions to predict bioavailability of radionuclides from soil as well as to predict possible contamination of animal products (milk and meat).     

Survival of Salmonellae During Pepperoni Manufacture

Survival of salmonellae in artificially contaminated beef-pork mixtures (approximately 10(4) salmonellae/g) was studied in pepperoni prepared by either a natural flora or lactic starter culture fermentation or in nonfermented sausages. The pepperoni did not become salmonellae free during the usual commercial 15 to 30-day drying period. Salmonella dublin was present in all products, fermented or unfermented, after 42 to 43 days of drying. At a lower level of contamination, 10(3)/g, S. dublin could not be recovered from starter culture-fermented pepperoni after 14 days of drying but persisted in the natural flora-fermented sausage. S. typhimurium (initial count, 10(4)/g) was absent after 42 days of drying when starter culture was used to ferment the pepperoni, but was still present in the natural flora-fermented and unfermented products. S. dublin, host adapted to cattle, or S. choleraesuis, host adapted to swine, had similar survival patterns in beef pork, or beef-pork pepperoni. Heating salmonellae contaminated beef-pork pepperoni (after fermantation but before drying) to an internal temperature of 60 C (trichinae inactivating) eliminated the food-borne pathogen from the sausage product.     

Salmonellae Associated with Further-processed Turkey Products

"Further-processed" turkey products, prepared from chilled, eviscerated, and thawed carcasses at two commercial turkey-processing plants, were evaluated, for the presence of salmonellae. These organisms were isolated from swab samples from 12% of chilled, eviscerated turkey carcasses, 27% of finished products, and 24% of processing equipment. The same serotypes as those found throughout a plant on any one visit were recovered from 31% of rinse-samples taken from hands and gloves of processing personnel. Salmonellae were found in samples taken on 37 of 48 visits; a greater number of recoveries were made on days when freshly killed turkeys were processed (87%) than when frozen-defrosted carcasses were processed (59%). The predominant serotype isolated from meat and environment usually changed from visit to visit. Salmonella sandiego and Salmonella anatum were the most frequent among 23 serotypes recovered. Most of the isolated serotypes are commonly associated with turkeys and have been incriminated as causative agents of human salmonellosis. The implication is that further-processed turkey products, if inadequately cooked by the consumer and if improperly refrigerated between the time of manufacture and consumption, could directly transmit salmonellae. These same products might also contaminate other foods by introducing salmonellae into food-preparation areas.     

The mechanisms maintaining epidemic foci of leptospirosis]

24,419 samples of blood serum, collected in the Azerbaijan SSR among different professional groups of the population, have been tested for leptospirosis. The comparison of the results with those obtained in the natural foci of leptospirosis and in the foci of this infection appearing as a consequence of human activities has made it possible to come to the conclusion that the epidemic foci of leptospirosis are maintained due to the existence of foci among cattle. The cases of contamination among persons professionally linked with large cattle breeding complexes have been found to exceed those among persons working at farms of a nonindustrial type.     

Listeria monocytogenes occurrence and characterization in meat-producing plants

AIMS: The prevalence, level of contamination and epidemiological profile of Listeria monocytogenes were investigated in two meat-producing plants during a 20-month period. METHODS AND RESULTS: Sampling for L. monocytogenes was carried out in a cattle slaughterhouse (n = 72) and a swine meat-processing plant (n = 68) during a 20-month period. Swabs and food samples were analysed with the most probable number (MPN) technique for L. monocytogenes and the isolated strains were characterized by AscI-restriction analysis pulsed-field gel electrophoresis (REA-PFGE). Contamination of meat and meat products was always at low level (below 50 MPN per gram). The seven L. monocytogenes positive samples isolated in the bovine slaughterhouse yielded strains with the same REA-PFGE profile. However, the seven strains isolated in the swine meat processing plant showed six different profiles. Two of them showed indistinguishable profiles with L. monocytogenes strains collected from other meat processing facilities located in the same area. SIGNIFICANCE AND IMPACT OF THE STUDY: The genotyping method is a valuable tool to investigate contamination sources. The study of REA-PFGE profiles indicated that environmental contamination was probably responsible for the persistence of over 16 months of one strain of L. monocytogenes in the cattle slaughterhouse. Several meat suppliers could be responsible for the contamination in the pig meat processing facility, and this is confirmed by the finding of some identical strain in other meat processing facilities located in the same area.     

Bacteriocinogenic LAB Strains for Fermented Meat Preservation: Perspectives,Challenges, and Limitations

Over the last decades, much research has focused on lactic acid bacteria (LAB) bacteriocins because of their potential as biopreservatives and their action against the growth of spoilage microbes. Meat and fermented meat products are prone to microbial contamination, causing health risks, as well as economic losses in the meat industry. The use of bacteriocin-producing LAB starter or protective cultures is suitable for fermented meats. However, although bacteriocins can be produced during meat processing, their levels are usually much lower than those achieved during in vitro fermentations under optimal environmental conditions. Thus, the direct addition of a bacteriocin food additive would be desirable. Moreover, safety and technological characteristics of the bacteriocinogenic LAB must be considered before their widespread applications. This review describes the perspectives and challenges toward the complete disclosure of new bacteriocins as effective preservatives in the production of safe and “healthy” fermented meat products.     

Yersinia in the water of wells near an area of irrigation with the effluents from a swine-breeding farm complex

Water taken from wells situated in the zone of irrigation with sewage water from a swine-breeding complex was studied. In 25.4% of samples Y. enterocolitica and Y. intermedia were detected. In winter and spring months twice as many strains were isolated in comparison with the number of strains isolated in summer and autumn. No Yersinia were isolated from control water samples taken from wells remote from the irrigation zone. The epidemiological relationship between a case of Yersinia infection and the use of infected well water was established.     

Rapid detection of salmonellae in poultry with the magnetic immuno-polymerase chain reaction assay.

Rapid detection of salmonellae in chicken meat was accomplished by using the magnetic immuno-polymerase chain reaction assay (MIPA). A direct polymerase chain reaction assay performed with chicken meat spiked with Salmonella typhimurium resulted in poor sensitivity (approximately 10(7) CFU/g of meat). The use of immunoseparation with a Salmonella serogroup B-specific monoclonal antibody improved the sensitivity, but enrichment was required for the detection of low levels of contamination. Enrichment for 6 h in either buffered peptone water, lactose broth containing tergitol-7, or selenite-cystine broth resulted in the detection of an initial inoculum of 100 CFU per g of meat. Enrichment of the salmonellae present on 25 g of spiked chicken meat for 24 h in either buffered peptone water or selenite-cystine broth before detection by the MIPA yielded a detection limit of approximately 0.1 CFU/g of meat. A detection limit of approximately 1 CFU/g of meat was obtained when the spiked meat was stored at -20 degrees C before enrichment for 24 h and analysis with the MIPA. Although the MIPA was developed for S. typhimurium, a MIPA in which a panel of six monoclonal antibodies specific for Salmonella serogroups A through E was used detected the presence of 0.1 CFU of Salmonella enteritidis per g of chicken meat. These data indicate that the method is applicable to other commonly isolated serotypes.     

接触猪职业人群和对照人群戊型肝炎感染率比较研究

近年来戊型肝炎（Hepatitis E,HE）被怀疑是一种人兽共患病,猪是其重要的宿主.通过在HE流行区比较接触猪人群和对照人群HE感染率,评价接触猪对人群的HE感染的风险.在浙江省北部某县采用限制研究对象的群组匹配的横断面调查,对同地区同年龄段的接触猪人群和对照人群进行问卷调查,采集血液并检测抗HE抗体.研究发现,接触猪人群和对照人群的年龄大致相当,但前者男性比例较高.接触猪人群抗HE抗体感染率（254/340,74.71%）明显高于对照人群（319/512,62.30%）.经过分层分析和多因素非条件Logistic回归分析,平衡性别和年龄因素后,接触猪仍能增加约50%人群的HE感染风险.随着接触年数的增加,其风险也增加,接触猪5～14年和15年以上人群分别比对照人群增加65%和157%的HE感染风险.接触猪人群男性、女性和合计的标化感染率分别为72.30%、65.67%和70.92%,均高于对照人群（69.87%、51.82%和60.80%）,尤其以女性更为明显.在HE流行区,接触猪可能增加人群HE感染风险,对女性的影响可能较大,随着接触猪年数的增加HE感染的风险也增加.由于本研究采用病因和结果同时出现的横断面研究,确切的接触猪和HE感染的关系需要建立合适的接触猪人群队列并结合详细的接触猪暴露调查得到阐明.     

An analysis of the dysentery epidemic process in Blagoveshchensk

The retrospective analysis of dysentery morbidity in Blagoveshchensk for the period of 1960-1987 was made. The regularities linking general natural and biological factors triggering the epidemic process with dysentery morbidity among the population are emphasized. The study revealed that under the conditions of Blagoveshchensk dairy products were of major epidemic importance among factors contributing to the transmission of dysentery. Such a factor as flies also had a definite influence on the epidemic process of dysentery. Another risk factor was drinking water which influenced the epidemic process both directly and indirectly through dairy products and, probably, other foodstuffs. Reliable correlation between dysentery morbidity among the population and the quality of dairy products, tap water and the number of flies was established.     

Salmonellae in Fish Meal Plants: Relative Amounts of Contamination at Various Stages of Processing and a Method of Control

Previous studies have shown that Menhaden fish meal, a common ingredient of animal feeds, is frequently contaminated with salmonellae. Animals that eat contaminated feed may become infected. If they, in turn, are eaten by humans, they may be a means by which salmonellae are introduced into the human population. Epidemiological studies of the fish-meal industry were carried out to determine the sources of salmonellae in fish meal and the factors affecting the persistence and survival of salmonellae during the processing of fish meal. Examination of 190 fish immediately after they came from the Gulf of Mexico revealed no salmonellae, but salmonellae were frequently isolated from samples of fish taken from the boats when they arrived at the plants. Salmonellae were also frequently isolated from dockside water at each of the plants. Approximately 50% of the samples taken in the raw fish processing areas were contaminated with salmonellae. The percentage of samples yielding salmonellae decreased progressively through the various sequences of processing, but more than 15% of the samples taken from the finished products were also positive. Salmonellae were isolated from the raw area of the plant most frequently while the plant was operating and less frequently when the plant was idle, whereas in the processing area of the plant the reverse was true. Salmonellae appeared to survive and multiply in the processing area of the plant while the plant was idle, which resulted in contamination of the first portion of each day's production. Salmonellae in the processed fish meal were reduced to nondetectable levels by reprocessing the first 45 min of each day's production.     

Improved Isolation of Salmonellae from Naturally Contaminated Meat Products by Using Rappaport-Vassiliadis Enrichment Broth

A total of 454 specimens of meat products were examined for salmonellae by using five procedures of enrichment. The use of a selective motility medium, inoculated from enrichment in Muller-Kauffmann broth, resulted in an increase in the number of positive specimens. However, simple enrichment in Rappaport-Vassiliadis broth, after preenrichment, was more sensitive and specific for recovering salmonellae than the selective motility medium-Muller-Kauffmann broth method.     

The epidemiological surveillance of poliomyelitis in the Ukraine]

Correlation has been revealed between the circulation of polioviruses among the population and environmental objects. A rise in the circulation of polioviruses, type I, was caused by a decrease in collective immunity to this virus type. Water supply and sewage system purification was found ineffective with respect to enteroviral contamination. Vaccinal prophylaxis, carried out for many years, did not lead to the elimination of poliovirus strains, genetically different from vaccine ones.     

Longevity of Salmonella typhimurium in Tilapia aurea and water from pools fertilized with swine waste.

Salmonella typhimurium declined rapidly when inoculated into Tilapia aurea culture pools fertilized with fresh swine waste. Within the water column, a 95% decline of viable cells occurred during the first 6 h. Isolation of viable salmonellae was possible at 16 days post-inoculation, but not at 32 days. Similarly, salmonellae could be detected in the viscera and epithelium of T. aurea at 16 days, although not at 32 days. Salmonellae were not isolated from the fish flesh, nor was there evidence of septicemic infection.