The reported prevalence of Salmonella in different feed materials varies considerably between different countries which is most likely due to differences in the sampling and isolation methods used. Salmonella positive ingredients are treated with organic acids and re-tested for Salmonella before they can be used in the feed manufacturing. Imported feed raw materials are sampled for salmonella according to a sampling programme and must remain in quarantine until the analytical results are completed. Scrapings and dust samples from critical control points (CCPs) in the processing line are analysed for Salmonella on a weekly basis giving a rapid alert if Salmonella is detected. The present Swedish control program for feed, based on hazard analysis of critical control point (HACCP) principals in the feed mills, was initiated in 1991 by the feed industry. Salmonella control of food producing animals has a long history in Sweden and started already in the late 1950s. It was found that the source of infection was a contaminated cooler for the pelleted feed where multiplication of Salmonella occurred in the humid and warm coatings inside the cooler. Cubana in Sweden occurred in a large number of pig farms where the source of infection was traced back to a feed mill that produced pelleted pig feed, indicating the potential effects of feed contamination for further dissemination of Salmonella in the food chain. pointed out that contaminated animal feed is a significant source of infections in pigs. , a strong link between Salmonella contamination in feed mills and infections in chickens that received feed from the contaminated feed mills could be established. Agona has caused considerable human illness every year in United States. Agona, was traced back to Peruvian fish meal used as an ingredient in the feed manufacturing. A major outbreak of human salmonellosis in the United States, United Kingdom, Israel and the Netherlands back in 1970, caused by the, at the time, uncommon serotype S. Investigations by the US Food and Drug Administration (FDA) showed that protein-based animal feed are frequently contaminated with Salmonella enterica. The presence of Salmonella in animal feed and feed ingredients is not unusual and cases of human illnesses have been reported where the source of infection were found to be contaminated animal feed. It is well known that Salmonella contamination of animal feed can be disseminated to food producing animals and further down the food chain, causing big economic losses and most importantly be a threat to animal and public health. Salmonella enterica contamination of foodstuffs is a considerable human health problem with more than 170 000 human cases reported in the EU in 2005. However, the detection levels for different feed and feed ingredients varied considerably. The results of this study showed that the accuracy, sensitivity and specificity of the investigated cultural methods were equivalent.
Compared to other feed materials palm kernel meal showed a higher detection level with all serotypes and methods tested. However, Müller-Kauffmann tetrathionate-novobiocin broth (MKTTn), performed less well due to many false-negative results on Brilliant Green agar (BGA) plates. The results obtained with all three methods showed no differences in detection levels, with an accuracy and sensitivity of 65% and 56%, respectively. For all methods pre-enrichment in Buffered Peptone Water (BPW) were carried out followed by enrichments in the different selective media and finally plating on selective agar media. Yoruba were added to each feed material, respectively. Four different levels of the Salmonella serotypes S. Five different feed materials were investigated, namely wheat grain, soybean meal, rape seed meal, palm kernel meal, pellets of pig feed and also scrapings from a feed mill elevator.
#Salmonella on xld iso#
In a comparative study the ability of the standard method used for isolation of Salmonella in feed in the Nordic countries, the NMKL71 method (Nordic Committee on Food Analysis) was compared to the Modified Semisolid Rappaport Vassiliadis method (MSRV) and the international standard method (EN ISO 6579:2002). In order to increase our present knowledge about possible feed transmission it is important to know that the present isolation methods for Salmonella are reliable also for feed materials. Animal feed as a source of infection to food producing animals is much debated.
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