A Systematic Review of Bacterial Foodborne Outbreaks Related to Red Meat and Meat Products.

Our investigation focused on foodborne outbreaks related to meat and meat products, published in peer-reviewed journals in the period 1980-2015. Most of the outbreaks, investigated in this study, were caused by Escherichia coli and Salmonella, causing 33 and 21 outbreaks, respectively, mostly in Europe and the United States. In the E. coli outbreaks, the total number of reported cases was 1966, of which 1543 were laboratory confirmed. The number of cases requiring hospitalization was 476, of whom 233 cases had a hemolytic-uremic syndrome (HUS), and the reported deaths were 32. All of the E. coli outbreaks, except four, were caused by serovar O157:H7. The other four outbreaks were caused by the following serovars: O111:H8, O26:H11, O111, and O103:H25. Fresh processed meat products were the category most frequently implicated. In the Salmonella outbreaks, the total number of all reported cases was 2279, of whom 1891 were laboratory confirmed. The number of reported cases requiring hospitalization was 94, and seven were reported dead. Regarding Salmonella, eight serovars caused those outbreaks. The most common serovar causing Salmonella-related outbreaks was Salmonella Typhimurium. The food category most frequently implicated in those outbreaks was raw-cured fermented sausages. Other organisms linked to meat-associated outbreaks, but less frequently reported, were Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, Clostridium botulinum, and Listeria monocytogenes. Issues of the burden of outbreaks, the challenges of comparing global outbreaks, food attribution, and how the meat industry works to meet consumer demands while maintaining food safety are discussed.

Effects of hygienic treatments during slaughtering on microbial dynamics and contamination of sheep meat.

The aims of this study were to investigate bacterial dynamics in the sheep meat chain, from fleece to meat trimmings, using both quantitative and qualitative analyses, and to study the effects on microbial load associated with the hygienic interventions of: i) shearing sheep immediately before slaughter, ii) manual steam vacuum pasteurisation, iii) hot water pasteurisation of carcasses, followed by iv) chilling. A further aim was to provide evidence to determine whether or not unshorn sheep should be handled in a processing line separate from that of shorn sheep in Norwegian abattoirs. A total of 176 surface swab samples were collected from three sites along the value chain: i) on fleeces, ii) on carcasses at the end of the slaughter line, and iii) on carcasses after chilling for 24h, and 32 samples were collected from meat trimmings. The results showed that Aerobic Plate Counts (APC) were lower for the shorn group compared to the unshorn group, both on carcasses before chilling and after chilling (difference of 0.8 and 0.9logCFU/1000cm(2) (p≤0.05), respectively) and in meat trimmings (difference of 0.5logCFU/g (p≤0.05)). Hygienic treatments were used on carcasses derived from unshorn sheep, and steam vacuum treatment reduced Escherichia coli, Enterobacteriaceae, and APC before chilling by 1.2, 1.0, and 0.6logCFU/1000cm(2) (p≤0.05), respectively, and hot water pasteurisation, in addition to chilling, reduced E. coli, Enterobacteriaceae, and APC by 0.7, 1.0, and 0.9logCFU/1000cm(2) (p≤0.05), respectively, compared with untreated carcasses. The effect of chilling was shown by the significant reduction of number of carcasses where E. coli were detected; from 65% (13/20) of the shorn group before chilling to 35% (7/20) after chilling, and from 90% (36/40) to 45% (9/20) of the unshorn group. Sequencing of the 16S rRNA gene derived from 316 colonies of Enterobacteriaceae showed a tendency for the relative proportion of the genus Escherichia/Shigella, compared with other genera within Enterobacteriaceae, to be greater for unshorn, untreated sheep than from the other groups at the sampling locations along the meat chain. The study showed that steam vacuum and hot water pasteurisation reduced the contamination of carcasses derived from unshorn sheep, down to the level of the shorn group, and thus can replace the separate processing line for unshorn sheep. Indeed, the low microbial contamination in meat trimmings for all groups indicates that the separate processing line is unnecessary.

Reduction of verotoxigenic Escherichia coli in production of fermented sausages.

After a number of foodborne outbreaks of verotoxigenic Escherichia coli involving fermented sausages, some countries have imposed regulations on sausage production. For example, the US Food Safety and Inspection Service requires a 5 log(10) reduction of E. coli in fermented products. Such regulations have led to a number of studies on the inactivation of E. coli in fermented sausages by changing processing and post-processing conditions. Several factors influence the survival of E. coli such as pre-treatment of the meat, amount of NaCl, nitrite and lactic acid, water activity, pH, choice of starter cultures and addition of antimicrobial compounds. Also process variables like fermentation temperature and storage time play important roles. Though a large variety of different production processes of sausages exist, generally the reduction of E. coli caused by production is in the range 1-2 log(10). In many cases this may not be enough to ensure microbial food safety. By optimising ingredients and process parameters it is possible to increase E. coli reduction to some extent, but in some cases still other post process treatments may be required. Such treatments may be storage at ambient temperatures, specific heat treatments, high pressure processing or irradiation. HACCP analyses have identified the quality of the raw materials, low temperature in the batter when preparing the sausages and a rapid pH drop during fermentation as critical control points in sausage production. This review summarises the literature on the reduction verotoxigenic E. coli in production of fermented sausages.

Fungal growth pattern, sources and factors of mould contamination in a dry-cured meat production facility.

The aims of this study were to investigate the patterns of fungal growth on dry-cured meat products, identify the important sources and factors of contamination and recommend intervention measures. The production processes of two smoked dry-cured hams and one unsmoked dry-cured leg of lamb were studied. A longitudinal observational study was performed to collect 642 samples from the meat, production materials, room installations and indoor and outdoor air of the production facility. Standard mycological isolation and identification procedures were followed. Totally, 901 fungal isolates were obtained; of which 57% were moulds while 43% were yeast. Yeasts were dominant on meat surfaces by covering 64% of the isolates. Mould growth was not observed until late in the dry-ripening stage. Yeasts and moulds were isolated from half of the environmental samples, of which moulds contributed by 80%. More than 39 mould species were isolated from the entire production process with a 77% contribution by the species of Penicillium. Penicillium nalgiovense dominated the species composition of moulds isolated from the products and the production environment. A preliminary bioassay analysis on bacterial colonies indicated that most of the P. nalgiovense isolates have the ability to produce penicillin. Such isolates might produce penicillin on the products and can become potential food safety hazards. Improper pressing at the salting process, the air quality in salting, brining and smoking rooms and activities in the sorting room were identified as important factors and sources of fungal contamination. Technical solutions and organized production activities that reduce crack formation, airborne spore concentration and improve air circulation in the facility are recommended as intervention measures.

A case-control study of scrapie Nor98 in Norwegian sheep flocks.

Scrapie is a fatal, neurological disease of sheep and goats and belongs to the transmissible spongiform encephalopathies. In 1998, a new type of scrapie, designated scrapie Nor98, was detected in Norway. Scrapie Nor98 differs from classical scrapie in the distribution of pathological changes and of the scrapie prion protein, the Western blot profile of the prion protein, and with isolated cases usually being observed in the case flocks. In 2004, a case-control study was conducted on scrapie Nor98 with 28 cases and 102 randomly selected controls. The questionnaire included questions on demographic data, animal contact between sheep flocks, indirect contact with equipment, use of concentrate feed and supplemental feeds, and use of medicines and vaccines. The data were analysed by using logistic regression with the sheep flock as the statistical unit. In the final model, the detection of scrapie Nor98 was related to the practice of not removing all afterbirths, the use of vitamin and mineral feed supplements, the absence of concentrate feed of swine or poultry on the farm and the presence of dogs on the farm. The results show that the epidemiology of scrapie Nor98 differs from that of classical scrapie in that no risk factors that indicate transmission of scrapie Nor98 between flocks by movement or direct contact between animals were found. Furthermore, the association between scrapie Nor98 and mineral intake shown herein should be explored further. Although the possibility that scrapie Nor98 has a low transmissibility between animals under natural conditions cannot be ruled out, the results would also be in accordance with a spontaneous aetiology.