Suchergebnisse

Abstract Background Contagious Agalactia (CA) is one of the major animal health problems in small ruminants because of its economic significance. Currently, four Mycoplasma spp. have been associated with this syndrome: M. agalactiae , M. mycoides subsp. capri , M. capricolum subsp. capricolum and M. putrefaciens . Their presence has been evaluated in several studies conducted in CA-endemic countries. However, previous Spanish studies have been focused on caprine CA, and there is a knowledge gap regarding which Mycoplasma species are present in sheep flocks from Spain, which has the second highest number of sheep amongst the 27 European Union member states. Consequently, we investigated the presence and geographic distribution of the four CA-causing mycoplasmas in Spanish dairy sheep farms. This is the first time such an investigation has been performed. Results Three hundred thirty nine out of 922 sheep flocks were positive for M. agalactiae by real time PCR (36.8%) and 85 by microbiological identification (9.2%). Interestingly, all 597 milk samples assessed for the presence of M. mycoides subsp. capri , M. capricolum subsp. capricolum and M . putrefaciens tested negative. To evaluate the intermittent excretion of the pathogen in milk, we sampled 391 additional farms from 2 to 5 times, resulting that in 26.3% of the cases a previously positive farm tested negative in a later sampling. Conclusions M . agalactiae was the only Mycoplasma species detected in the study area showing a high frequency of presence and wide distribution. Therefore, the establishment of a permanent surveillance network is advantageous, as well as the implementation of control and prevention measures to hinder the dissemination of M. agalactiae and to prevent the entrance of other Mycoplasma species.

We developed a real-time PCR assay for the quantitative detection of Clostridium tyrobutyricum, which has been identified as the major causal agent of late blowing in cheese. The assay was 100% specific, with an analytical sensitivity of 1 genome equivalent in 40% of the reactions. The quantification was linear (R2 > 0.9995) over a 5-log dynamic range, down to 10 genome equivalents, with a PCR efficiency of >0.946. With optimized detergent treatment and enzymatic pretreatment of the sample before centrifugation and nucleic acid extraction, the assay counted down to 300 C. tyrobutyricum spores, with a relative accuracy of 82.98 to 107.68, and detected as few as 25 spores in 25 ml of artificially contaminated raw or ultrahigh-temperature-treated whole milk. ; This work was supported by the Agrarian Experimental Plan of the ITACyL/Junta de Castilla y León and the European Union's Marie-Curie Mobility Program (contract MEIF-CT-2005-0011564). L.L.-E. received a Ph.D. studentship from the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), D.R.-L. is a fellow of the European Union's Marie-Curie Mobility Program, and M.H. holds a contract from the INIA. ; Peer reviewed

Processed cheese from cow's milk is one of the most consumed dairy products worldwide. Since this product is defined as ready-to-eat, foodborne pathogens such as Listeria monocytogenes can represent a health concern for susceptible populations. In this study, the individual and combined kinetic behaviour of four L. monocytogenes serogroups (namely, 1/2a, 1/2b, 1/2c and 4b) persistently isolated from a Spanish cheesemaking factory was modelled on grated cheese at different isothermal conditions (4 and 12 °C) during a 120-days period. The serogroup variability was characterized over the storage time by the isolation and identification of the different serogroups in the cocktail containing the four strains. This processed cheese did not support the growth of L. monocytogenes during storage. Survival patterns described by the log-linear type model indicated a high variability of L. monocytogenes serotypes at the tested temperatures: L. monocytogenes serogroup 4b showed a more rapid decrease rate at 4 °C than at 12 °C, while the opposite trend was found for the rest of serogroups and the L. monocytogenes cocktail containing all the strains. Survival rate of L. monocytogenes serogroup 1/2c at 4 °C was 0.007 log CFU/d being the most resistant serotype while at 12 °C, serogroup 1/2a showed the lowest survival rate (0.011 log CFU/d), thus showing a prolonged survival at this temperature. This study highlights the potential implications of L. monocytogenes contamination in processed cheese and shows that serogroup variability should be considered when evaluating survival patterns in contaminated products. Finally, the predictive models developed here could be useful to assist food operators to set specific storage conditions and formulations to avoid L. monocytogenes growth and survival in grated cheeses. ; European Union (EU) funded Integrated Project PROMISE (project number 265877; 7th Framework Programme)

SIMPLE SUMMARY: Salmonella spp. is a bacterium that places human health at risk by consuming eggs and poultry. In the European Union, the use of antimicrobials to treat salmonellosis in aviculture is no longer permitted due to the resistance to treatment of some bacteria, such as Salmonella spp. For this reason, compounds derived from natural food sources are being increasingly tested to assess their efficacy against Salmonella spp. In this study, chickens were given dietary supplements in the form of fermented defatted 'alperujo', a modified olive oil by-product, after which they were infected with Salmonella Typhimurium. The chickens given the supplement showed a healthy gut and a reduction in the amount of Salmonella spp. in the cecum. In conclusion, this olive oil by-product may contribute to preventing and controlling salmonellosis in farms, as well as reducing environmental contamination. ABSTRACT: Salmonella spp. contaminates egg and poultry meat leading to foodborne infections in humans. The emergence of antimicrobial-resistant strains has limited the use of antimicrobials. We aimed to determine the effects of the food supplement, fermented defatted 'alperujo' (FDA), a modified olive oil by-product, on Salmonella Typhimurium colonisation in broilers. One hundred and twenty 1-day-old broilers were divided into four experimental groups—two control groups and two treated groups, and challenged with S. Typhimurium at day 7 or 21. On days 7, 14, 21, 28, 35, and 42 of life, duodenum and cecum tissue samples were collected for histopathological and histomorphometric studies. Additionally, cecum content was collected for Salmonella spp. detection by culture and qPCR, and for metagenomic analysis. Our results showed a significant reduction of Salmonella spp. in the cecum of 42-day-old broilers, suggesting that fermented defatted 'alperujo' limits Salmonella Typhimurium colonization in that cecum and may contribute to diminishing the risk of carcass contamination at the time of slaughter. The improvement of the ...

Hepatitis E virus (HEV) is an important enteric agent that can circulate in swine; it is excreted in manure, and of zoonotic interest. The present study investigated, by RT-qPCR, the circulation of HEV in swine manure from different types of pig farms (maternity, nursery, and grow-finish farms) in Santa Catarina State, the major pig production area of Brazil, and also evaluated the HEV removal efficiency of psychrophilic anaerobic biodigesters (PABs). While HEV was consistently detected in manure from grow-finish pig farms (>4 log HEV genome copies (GC) L(−1)), the virus was not detected in manure from maternity and nursery farms. These findings suggest a potential high biosafety status during primary-swine production, with a subsequent contamination in grow-finish production. The anaerobic biodigestion process reduced more than 2 log(10) HEV GC in the processed swine manure. However, the virus concentration in final effluent remained high, with an average value of 3.85 log(10) HEV GC L(−1). Consequently, our results demonstrate that PABs can be a robust tool for effective inactivation of HEV, while reinforcing the need for sanitary surveillance and legislation of swine manure-derived biofertilizers, to avoid the spread of zoonotic enteric pathogens such as HEV.