Whole genome sequencing: an efficient approach to ensuring food safety

Whole genome sequencing is an effective, powerful tool that can be applied to a wide range of public health and food safety applications. A major difference between WGS and the traditional typing techniques is that WGS allows all genes to be included in the analysis, instead of a well-defined subset of genes or variable intergenic regions. Also, the use of WGS can facilitate the understanding of contamination/colonization routes of foodborne pathogens within the food production environment, and can also afford efficient tracking of pathogens entry routes and distribution from farm-to-consumer. Tracking foodborne pathogens in the food processing-distribution-retail-consumer continuum is of the utmost importance for facilitation of outbreak investigations and rapid action in controlling/preventing foodborne outbreaks. Therefore, WGS likely will replace most of the numerous workflows used in public health laboratories to characterize foodborne pathogens into one consolidated, efficient workflow

Meat safety in the climate change context

Climate change is a global phenomenon in the 21st century which may have impact on the occurrence of meatborne hazards at multiple points in the meat chain continuum, from the primary production through to consumption. The assurance of meat safety is a complex task, which requires strong inter-sectoral cooperation between relevant stakeholders such as Competent Authority, Academia, Food Industry and Consumers. The emerging food safety risks due to climate change may pose a serious challenge to the meat safety control system. Therefore, a better understanding of anticipated changes would be of the utmost importance for governments to ensure preparedness

Improved sensitivity and reproducibility of the PCR method for detection of Listeria spp. and L. monocytogenes in milk

Listeria monocytogenes, prouzrokovač listerioze kod ljudi i životinja, je fakultativan intraćelijski mikroorganizam široko rasprostranjen u prirodi. U cilju izolacije i detekcije L. monocytogenes iz hrane koriste se tradicionalne mikrobiološke i nove molekularno-genetičke metode. Cilj ovog rada je bio povećanje osetljivosti i ponovljivosti PCR metode u detekciji L. monocytogenes u mleku. U tu svrhu, uzorci pasterizovanog mleka su kontaminirani serijskim razblaženjima sojeva L. monocytogenes 4b ATCC 119115 i Listeria innocua ATCC 33090. Dobijeni rezultati na veštački kontaminiranim uzorcima pasterizovanog mleka, ukazuju da osetljivost PCR metode zavisi od perioda inkubacije i izbora prajmera. Najbolji rezultati su dobijeni nakon 24 h inkubacije, pomoću prajmera za hlyA gen, kada je bilo moguće detektovati 1 ćeliju L. monocytogenes tj. 1 CFU/ml.Listeria monocytogenes is a facultative intracellular Grampositive bacterium, ubiquitous in nature and capable of causing listeriosis in humans and animals. Conventional microbiological techniques and modern molecular approaches are currently used for the isolation and detection of L. monocytogenes in food samples. The aim of this study was to improve the sensitivity and reproducibility of PCR for the detection of Listeria spp. in milk. For that purpose milk samples were artificially inoculated with serial dilutions of L. monocytogenes 4b ATCC 19115 and L. innocua ATCC 33090. The results obtained on artificially contaminated milk samples indicated that incubation time and target genes have an influence on the sensitivity of PCR detection. The best results were obtained after 24 h of preenrichment, with primers complementary to the hlyA gene, when it was possible to detect 1 CFU/mL of Listeria spp

Determination of staphylococcal enterotoxins in cheese by immunoenzyme assays

Staphylococcal food poisoning is one of the most common foodborne diseases resulting from the ingestion of staphylococcal enterotoxins (SEs) preformed in foods by enterotoxigenic strains of coagulase-positive staphylococci (CPS), mainly Staphylococcus aureus. The presence of enterotoxigenic strains of coagulase-positive staphylococci in raw milk during the production process leads to the contamination of products and outbreaks of alimentary intoxication. The problem of Staphylococcus aureus in cheese remains significant on a global level. Domestic cheese contaminated with enterotoxigenic staphylococci can result in the formation of enterotoxin, which can produce foodborne illness when the product is ingested. Due to microbiological contamination, microbiological criteria are tools that can be used in assessing the safety and quality of foods. In order to avoid foodborne illness, the Serbian Regulation on General and Special Conditions for Food Hygiene (Official Gazette of RS, No. 72/10) provides microbiological criteria for staphylococcal enterotoxins in dairy products

Food safety - the roles and responsibilities of different sectors

Serbia is a relatively small country but with a long tradition in food production, especially meat and meat products. Serbia, as part of its open negotiation process as a candidate country with the European Union (EU), started to harmonise its legislation with the EU, and has published a set of laws and regulations relating to the hygiene of food production and food safety, the official control of production and the welfare of animals. Therefore, the food safety system in Serbia is based on principles established in the EU. There is a need for cooperation of different sectors (government, food business operators and consumers) in the management of food safety, and every sector has its role and responsibility. This paper aims to provide analytical support for the process of upgrading safety and quality in Serbias food sector and explains the roles and responsibilities of different sectors in the food chain

The presence of Listeria spp. and Listeria monocytogenes in a chosen food processing establishment in Serbia

The aim of the study was to establish a protocol to evaluate the presence of Listeria spp. in food processing environments. The presence of Listeria spp. was evaluated in a selected restaurant in Serbia on three occasions. Samples were collected from 47 sampling spots in the commercial kitchen equipment and environment. The presence of Listeria spp. and Listeria monocytogenes were detected by conventional culture methods and by the PCR method. The obtained results showed that 23 swab samples were positive for Listeria spp. Interestingly, the swabs from the bread-cutting board and meat defrosting sink were positive for L. monocytogenes

Prevalence and antibiotic resistance of Salmonella spp. in meat products, meat preparations and minced meat

This study aimed to determine Salmonella spp. prevalence in meat products, meat preparations and minced meat. Over a period of three years, a total of 300 samples were taken (100 RTE meat products, 100 meat preparations and 100 minced meat) and examined for the presence of Salmonella spp. Sampling was carried out at the warehouses of the food manufacturers. Salmonella spp. were not detected in RTE meat products, while 7% of semi-finished meat products (fresh sausages, grill meat formed and unformed) contained Salmonella, as did 18% of minced meats (minced pork II category, minced beef II category, mixed minced meat). The 25 Salmonella isolates obtained were examined for antibiotic resistance by the disk diffusion test, according to the NCCLS and CLSI guidelines. Isolates showed resistance to ampicillin and nalidixic acid (80%), tetracycline (72%), cefotaxime/clavulanic acid (48%), but not to gentamicin (8%) or trimethoprim/sulfamethoxazole (0%)

Microbiological safety and quality of salmon: Health benefits and risk

A total of 703 samples were tested over 1-year period. Listeria monocytogenes was isolated from 12.4% and 2.3% of fish and environmental swabs, respectively. The ratio of n-6/n-3 which is between 1:1 and 4:1, as more desirable parameter of the lipid quality for nutritive benefit e.g. reducing the risk of many diseases, in the fresh salmon, cold and hot smoked salmon was close to 1:1 (fresh salmon, 1.28; cold smoked salmon, 0.98; hot smoked salmon, 1.59). The fatty acid composition of smoked salmon products was also expressed as mg 100 g-1 which is important from the nutritional point of view. The examined salmon products had a high content of eicosapentaenoic acid and docosahexaenoic acid (742 to 1567 mg 100g-1) and fulfill requirements for their sufficient contents of recommendations in the World. On the other hand, cold smoked salmon can be naturally contaminated with low numbers of L. monocytogenes. This could represent a serious hazard for susceptible individuals or 'YOPI' (young, old, pregnant or immuno- compromised individuals)

Influence of two different culture media on biofilm formation by Listeria monocytogenes isolated from a small-scale meat processing facility

In this study, 20 Listeria monocytogenes isolates detected in a food processing environment and food products were tested for biofilm-forming ability in two different culture media: Tryptone Soya Broth and Luria Bertani Broth. Statistical analysis of the data obtained was performed with the MINITAB software package, version 16.0. The two-sample t-test and confidence interval were used for data analysis. Significant differences between the isolates were observed in the ability to form biofilms

Changes in total viable count and TVB-N content in marinated chicken breast fillets during storage

Marination is a popular technique for enhancing meat properties. Depending on the marinade type and ingredients added, marination can improve sensory, chemical and microbiological quality of meat products. In this study, the total viable count and total volatile basic nitrogen (TVB-N) content in marinated chicken breast fillets were investigated. The possible correlation between bacterial growth and formation of TVB-N was also tested. Chicken breast fillets were immersed in a solution of table salt (as a control) orthree different marinades, which consisted of table salt, sodium tripolyphosphate and/or sodium citrate, and stored in air for nine days at 4 +/- 1 degrees C. Analyses of the total viable count and TVB-N were performed on days0, 3, 6 and 9 day of storage. The total viable count gradually increased in all examined groups, and statistically significant differences (p<0.01; p<0.05) between treatments on days0, 3 and 6 day of storage were established. TVB-N values in marinated chicken were significantly higher (p<0.01; p<0.05) compared to the control. Using the multiple linear regression, a positive correlation between total viable count and formation of TVB-N in chicken marinated with sodium citrate was established (p<0.05), while the intensity of TVB-N formation was lowest in chicken marinated with sodium tripolyphosphate