Sava Buncic

Occurrence of Escherichia coli O157 on hides of slaughtered cattle

Aims:  To obtain the first information on the occurrence of Escherichia coli O157 on hides of slaughtered cattle in Serbia.

Scientific Opinion on a quantitative estimate of the public health impact of setting a new target for the reduction of Salmonella in laying hens

Public health risks of Salmonella infection in laying hens (Gallus gallus) can be associated with exposure through four different pathways: internally contaminated table eggs, externally contaminated table eggs, egg products and meat from spent hens. In relation to eggs, Salmonella Enteritidis is by far the serovar most frequently associated with human illness, and exposure through eggs that are internally contaminated with this serovar has a higher public health significance than exposure to externally contaminated eggs. A mathematical model, using reported field data from two EU Member States (MSs), suggests a linear relationship between the investigated scenarios of flock prevalence for Salmonella Enteritidis and the number of contaminated eggs that would be laid. However, the absolute public health impact of the assessed flock prevalence scenarios is highly uncertain due to lack of data on the number of contaminated eggs produced by infected flocks and on the true number of egg-related human salmonellosis cases. It is suggested that public health benefits, similar to those obtained reaching lower Salmonella flock prevalences, may be achieved by implementing controls based on more sensitive sampling protocols. Diversion of eggs from flocks that are tested positive in the EU Salmonella control programme to the production of egg products subjected to heat treatment may lead to increased health risks as heat treatment of egg products should not be considered an absolute barrier to Salmonella contamination. Fresh meat from spent laying hens might carry a higher prevalence of Salmonella than meat from broiler flocks, in particular if sourced from Salmonella-positive flocks. The quantification of under-ascertainment and underreporting of human salmonellosis cases, improving knowledge on within-flock dynamics of Salmonella and harvesting data on production of Salmonella contaminated eggs under field conditions would contribute to improving the accuracy of future quantitative estimates.

The occurrence of Escherichia coli O157 in/on faeces, carcasses and fresh meats from cattle.

The aim of this study was to investigate whether Escherichia coli O157 is present in/on raw beef in Serbia. Correlated faecal and carcasses samples from 115 slaughtered cattle plus 26 uncorrelated carcass samples were examined. E. coli O157 detection and identification was performed using selective enrichment and immunomagnetic separation followed by selective media-plating and biochemical tests. The E. coli O157 occurrences were 2.6% in faeces and 2.8% on carcasses. The E. coli O157 occurrences were 0%, 6.2% and 2.1%, respectively, in 106 samples of beef trimmings, 48 samples of minced beef and 48 samples of batter intended for production of raw, fermented sausages. The results confirmed that faecal contamination is very important for the occurrence of E. coli O157 on beef carcasses. Furthermore, the present study revealed occasional presence of the pathogen in raw materials used for producing raw, fermented beef sausages.

Visual cleanliness scores of cattle at slaughter and microbial loads on the hides and the carcases

In two abattoirs, visual cleanliness of 100 cattle was assessed before slaughter (on a scale of 1 to 4). From each animal, two sponge swabs (approximately 2000 cm2 area, each) were taken: (a) from hide, immediately after sticking, and (b) from final carcase, but before chilling. In each swab sample, total viable count (TVC), Enterobacteriaceae count (EC) and the presence of Escherichia coli O157 were determined. The mean TVC/EC status of hides and final carcases differed significantly only between very dirty cattle (category 4) and all other less dirty or clean cattle (categories 1, 2 and 3), but not between the less dirty and clean cattle (between categories 1, 2 and 3). However, no clear relationship between the visual cleanliness of the hide and the occurrence of E coli O157 on hide or dressed carcases was observed. The study indicated the possibility that visual categorisation of cattle into only two main categories – one containing very dirty animals (category 4 in this work, corresponding to categories 4 + 5 in The UK Food Standards Agency system) and another containing all the other less dirty or clean animals (categories 1 + 2 + 3) – could be sufficient in practice

A Study of Haptoglobin Levels in Groups of Cattle and Pigs With and Without Abnormalities at Meat Inspection

A total of 96 bovines originating from 36 farms and 97 pigs from five farms were slaughtered in two multispecies abattoirs and subjected to official meat inspection and haptoglobin (Hp) testing using a single radial immunodiffusion method. No direct correlation between Hp level and specific postmortem abnormalities was found at individual cattle/pig level. However, at animal group level, the mean of Hp values (in both cattle and pigs) were statistically significantly higher in animals with abnormalities than in those without. The study indicated that the mean Hp value in groups of cattle or pigs can be useful as an overall objective indicator of the overall status of cattle/pig batches when analyzing the food chain information as a part of the antemortem inspection at abattoirs, but related specific Hp criteria are currently missing. Because of the large variability and nonspecific nature of Hp-related responses in cattle and pigs, establishing a single, reliable cutoff Hp value differentiating batches that may pose public health risks does not appear as a realistic approach presently. Rather, establishing wider, unsatisfactory/marginal/satisfactory ranges of batch-based Hp values indicating general appropriateness of the cattle/pigs source appears more promising. For that, wider Hp baseline studies are necessary at abattoir.

Trichinellosis in wild and domestic pigs and public health: a Serbian perspective

Among a large number of susceptible animal species, the domestic pig is the most important source of human Trichinella infection worldwide. Trichinellosis is commonly defined by two cycles; ‘domestic’ (in pigs on-farm) and ‘sylvatic’ (in wildlife). Under conditions on industrial farms (particularly indoor) with good hygienic practices and efficient management including biosecurity, combined with effective governmental/veterinary services, Trichinella transmission via the domestic cycle is unlikely. In countries effectively implementing these strategies and with officially recognised negligible risk of Trichinella in domestic pigs, testing for this parasite at meat inspection is no longer mandatory for slaughter pigs reared in integrated production. In other countries, testing for Trichinella of slaughtered pigs is a very important component of the control system. Under conditions on small farms with pigs having access to the outdoors and where control measures are poorly implemented, or are lacking, the domestic cycle can play a very important role in trichinellosis transmission. This possibility is further enhanced where socio-economic and political problems temporarily diminish the efficacy of the governmental/veterinary services. Additionally, the practice of making uncooked products from meats of uninspected domestic and/or wild pigs at home represents a major risk for human infection. The risk of further spreading trichinellosis is additionally exacerbated by increased globalisation in modern times, including increased movements of livestock, food and people. Traditional farming practices facilitating a mixture of domestic and sylvatic cycles of Trichinella need to be modified/improved so to ensure the separation of the cycles. Furthermore, hunters need to be educated to avoid leaving animal carcasses or their entrails in the field because this increases the probability of transmission to new hosts. Also, the farmers, the hunters and the consumers should be educated to freeze pork (including meat from wild boars) before its further home-processing into products, or to cook the product before consumption, or both, aimed at the larvae inactivation.