Development and application of RTi-PCR method for common food pathogen presence and quantity in beef, sheep and chicken meat

An Overview of Shiga-Toxin Producing Escherichia coli Carriage and Prevalence in the Ovine Meat Production Chain

Shiga-toxin producing Escherichia coli (STEC) are zoonotic foodborne pathogens that are capable of causing serious human illness. Ovine ruminants are recognized as an important source of STEC and a notable contributor to contamination within the food industry. This review examined the prevalence of STEC in the ovine food production chain from farm-to-fork, reporting carriage in sheep herds, during abattoir processing, and in raw and ready-to-eat meats and meat products. Factors affecting the prevalence of STEC, including seasonality and animal age, were also examined. A relative prevalence can be obtained by calculating the mean prevalence observed over multiple surveys, weighted by sample number. A relative mean prevalence was obtained for STEC O157 and all STEC serogroups at multiple points along the ovine production chain by using suitable published surveys. A relative mean prevalence (and range) for STEC O157 was calculated: for feces 4.4% (0.2-28.1%), fleece 7.6% (0.8-12.8%), carcass 2.1% (0.2-9.8%), and raw ovine meat 1.9% (0.2-6.3%). For all STEC independent of serotype, a relative mean prevalence was calculated: for feces 33.3% (0.9-90.0%), carcass 58.7% (2.0-81.6%), and raw ovine meat 15.4% (2.7-35.5%). The prevalence of STEC in ovine fleece was reported in only one earlier survey, which recorded a prevalence of 86.2%. Animal age was reported to affect shedding in many surveys, with younger animals typically reported as having a higher prevalence of the pathogen. The prevalence of STEC decreases significantly along the ovine production chain after the application of postharvest interventions. Ovine products pose a small risk of potential STEC contamination to the food supply chain.

Development of a PCR-based lateral flow strip assay for the simple, rapid, and accurate detection of pork in meat and meat products

In recent years, adulteration of meat and meat products has become a major food safety issue. PCR and real-time PCR technologies are mainstream methods used to identify animal-derived components. However, these technologies rely highly on costly equipment and professional technicians; they are therefore difficult to use in resource-limited settings. In this study, a novel, highly sensitive molecular assay, Pig-PCR-Strip (Pig specific polymerase chain reaction-Lateral flow strip), was developed for rapid detection of pig and swine-derived components. The assay is based on PCR amplification, hybridization of the PCR product to the probe, followed by detection using a strip format. Using this format, the PCR product can be detected by the naked eye within 3 min, and provides a basis for the migration of species-specific detection to a point-of-care (POC) microfluidic format. The Pig-PCR-Strip can detect pork components at a concentration of 0.01% in adulterated meat, and the limit of detection is up to 10 fg of target DNA. The assay was specific to pork and did not cross-react with other non-target species. It also can be used for commercial samples and complex food samples. It is a promising new tool for detection of pig-derived meat and can be rapidly modified for identifying other species. It could be widely used for solving problems related to meat quality assurance, species authentication, and traceability.

Research advances of DNA aptasensors for foodborne pathogen detection

Aptamers, referring to single-stranded DNA or RNA molecules can specifically recognize and bind to their targets. Based on their excellent specificity, sensitivity, high affinity, and simplicity of modification, aptamers offer great potential for pathogen detection and biomolecular screening. This article reviews aptamer screening technologies and aptamer application technologies, including gold-nanoparticle lateral flow assays, fluorescence assays, electrochemical assays, colorimetric assays, and surface-enhanced Raman assays, in the detection of foodborne pathogens. Although notable progress (more rapid, sensitive, and accurate) has been achieved in the field, challenges and drawbacks in their applications still remain to be overcome.