Foreign materials with a variety of types and sizes are found in food; thus, extraordinary efforts and various analytical methods are required to identify the types of foreign materials and to find out accurate causes of how they unintentionally enter food. In this study, human, cow, pig, mouse, duck, goose, dog, and cat were chosen as various types of animal hairs because they can be frequently incorporated into food during its production or consumption step. We morphologically analyzed them using stereoscopic, optical, SUMP method, and scanning electron microscopes, showing differences in each type. In addition, X-ray fluorescence spectrometer (XRF) was used to analysis chemical compositions (11Na~92U, Mass%) of samples. As a result, we observed that mammalian hairs were mainly composed of sulfur. Organic compounds of samples were further analyzed by fourier transform infrared spectroscopy (FT-IR) that can compare spectra of given materials; however, this method did not show significant differences in each sample. In this study, we suggest a rapid method for the identification of the causes and types of foreign materials in food.

In this study, two commercial PCR and ELISA test kits were examined for identification of eight animal species (beef, pork, chicken, duck, turkey, goat, lamb, and horse) from raw meat and meat products in Korea. The detection limit in RAW meat ELISA kit® on three types of meat samples blended with beef, pork and chicken, demonstrated that all meat species were differentiable down to 0.2%. RAW meat ELISA kit® on animal species resulted in differentiation rate of 94.5% for beef, 93.3% for pork, 90% for lamb, and 100% for chicken, duck, turkey, goat, and horse. In contrast, Powercheck Animal Species ID PCR kitTM resulted in 100% specificity at 0.05% limit of detection for all meat species. The detection limit of Cooked Meat ELISA kit® on mixed meat samples heat-treated with different temperatures and times, resulted in 0.1% for all heat-treated mixed meat except for chicken at 1.0%. Additionally, ELISA kit on sixty meat products resulted in specificity of 31.8% for ham, 13.6% for sausages, and 12.5% for ground processed products, and relatively low rate for more than 2 types of mixed meats. On the contrary, meat species differentiation using PCR kit showed higher percentage than that using ELISA kit®: 50.0% for ham, 41.7% for sausages, and 28.6% for ground processed meat. Futhermore, PCR kit on 54 dried beef meats detected pork genes in 13 products whereas ELISA kit showed negative results for all products. Hence, the possibility of cross-contamination during manufacturing process was investigated, and it was found that identical tumblers, straining trays, cutters and dryers were used in both beef and pork jerky production line, suggesting the inclusion of pork genes in beef products due to cross-contamination. In this study, PCR and ELISA test kits were found to be excellent methods for meat species differentiation in raw meat and heat-processed mixed meat. However, lower differentiation rate demonstrated in case of meat processed products raised the possibility of inclusion of other species due to cross-contamination during manufacturing process.

Precise, rapid and simple methods for species identification in animals are among the most important techniques in the livestock industry and research fields including meat classification. In this study, polymerase chain reaction (PCR) based molecular identification using inter species polymorphisms were examined by PCR-restriction fragment length polymorphism (RFLP) analysis for mitochondrial DNA (mtDNA) cytochrome b (CYTB) gene sequences among four mammalian livestock animals (cattle, horse, goat and pig). The results from PCR-RFLP analysis using the AluI restriction enzyme were also provided for the species-specific band patterns among CYTB gene sequences in these four species. The AluI-digestion for CYTB genes provided interesting migration patterns differentially displayed according to each species. Cattle and horse had one AluI-recognition site at different nucleotide positions and their AluI-digested fragments showed different band patterns on the gels. Pig had two AluI-recognition sites within the amplified CYTB sequences and produced three bands on the gels. Goat had no AluI-recognition site and was located at the same position as the uncut PCR product. The results showed the species-specific band patterns on a single gel among the four livestock animal species by AluI-RFLP. In addition, the results from blind tests for the meat samples collected from providers without any records showed the identical information on the species recorded by observing their phenotypes before slaughter. The application of this PCR-RFLP method can be useful and provide rapid, simple, and clear information regarding species identification for various tissue samples originating from tested livestock species.

Animal crude drugs (natural medicines derived from animal organs) have been widely used in various Chinese medicine for the therapeutic effects and for enhancement of immunologic functions. We found the specific identification methods using DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses for mitochondrial DNA (mt DNA) in order to discriminate between the animal species and organs as well as the placenta of humans. Species-specific PCR bands of D-loop mt DNA for equine, bovine, porcine, and human were 133 bp, 137 bp, 231 bp, and 240 bp, respectively. Porcine organs were identified using restriction enzyme, HphI cut into two subfragments, 36 bp and 195 bp bands in the heart, spleen, and liver, except for kidney. The heart and liver of porcine were identified using restriction enzyme, SpeI cut into two subfragments, 84 bp and 147 bp bands, except for kidney and spleen. Bovine organs were cut into 68 bp and 69 bp bands in the liver, kidney, and spleen using NalIV, except heart and placenta. Placentas of bovine and humans were easily identified using each primer. Our results suggest that sequencing of mt DNA and its PCR-RFLP methods are useful for identification and discrimination of inter- and intra-specific variations in equine, bovine, porcine, and human by routine analysis.

  Food and Agriculture Organization (FAO) and many countries make an effort to conserve and utilization of animal genetic resources to prepare for our unpredictable future. In order to protect the customer and the producer from the animal diseases and unj