Better tests are needed because of the possibility that a product claimed to be from one animal could well be adulterated with meat from another: an experiment reported in January 2014 in the Journal of Food Science Technology, for example, analysed 224 meat products using PCR and PCR-RFLP* and found that 7.58% of the samples actually contained haram (unlawful or forbidden) meat. Similarly, a study from the Asian Australasian Journal of Animal Sciences published October 2014, also using PCR-RFLP, showed that nearly half (45%) of all meatballs from the local market in the Yogyakarta region in Indonesia suffered from pork contamination, although meatball shops in the Surabaya region were free of it.
In February 2014, Food Chemistry published an experiment on detecting the adulteration of meat products with pork with another PCR method, the assay of mitochondrial D-loop. The method worked for raw, cooked (at 60, 80 and 100°C), autoclaved (121°C) and microwave-oven processed pork, and could detect as little as 10 picograms (a picogram is 10-12 of a gram) of pork in meat from other species.
Another PCR assay, for dog meat adulteration, was described in Meat Science in August 2014. A blind test, one where researchers cannot tell the origin of the samples, showed that the method can reliably detect as little as 0.04 nanograms (a nanogram is 10-9 of a gram) of dog DNA mixed in with chicken or beef meatballs.
Another method was described in the Journal of Agricultural and Food Chemistry, published in October 2014. A method that combines liquid chromatography with mass spectrometry (often referred to as HPLC-MS) provides fast, sensitive detection of horse and pork in highly processed food. As little as 0.24% pork or horse in beef could be detected, even if the meat had already been cooked, with the samples ready for testing in 2 minutes.
*RFLP stands for restriction fragment length polymorphism.