It was recently reported that the Department of Islamic Development Malaysia (JAKIM) had confirmed that a particular brand of dairy product was non-halal after it was found to contain porcine DNA. This discovery not only affects consumers of the product but also renders other products, which use it as an ingredient, non-halal. This clearly highlights a case of inaccurate food labelling, an issue which is of great concern to most consumers of edible products.

Consumers come from various backgrounds and unique lifestyles, especially in a multicultural country like Malaysia. Many people are committed to observing food restrictions, which could be due to religious principles, lifestyle, food allergies or medical requirements. For these consumers, food labels are imperative in helping them make the right purchase. With this in mind, it is essential that food manufacturers accurately and truthfully label their products. To protect the rights of consumers, the sources and composition of all products have to be properly tested and verified prior to the products being sold. For this purpose, DNA-based methods can be employed to identify and detect traces of contamination in a product. Using specific DNA sequence regions, primers or probes unique to specific meat or plant species can be designed.

A suitable sequence region to use for probe design is the mitochondrial DNA (mtDNA) of various animals or plants. The mtDNA sequence is often used in population genetics studies as its gene content is believed to be strongly conserved. The existence of multiple copies of mtDNA in the cell also makes DNA amplification relatively easier. Using the cytochrome b sequence of Sus scrofa (wild pig) as an example, users can submit the sequence as a query on SynaProbe™ to design unique probe sequences to detect traces of pork. The specificity of these probes can be further verified with SynaHybridise™ to ensure accurate identification and detection of the targeted porcine species. In the example, the hybridisation of the probe to various breeds and isolates of the meat samples highlights the success of the probe in identifying the meat species, regardless of its breed.

The designed short sequences display much flexibility in terms of their application. Polymerase chain reaction (PCR) is already commonly employed in laboratory testing to provide specific and sensitive detection of trace contaminants in food products. While PCR is a hugely popular option, users may also consider microarray testing. The inclusion of hundreds to thousands of probes per microarray chip might potentially allow for the simultaneous detection of multiple contaminants within a product, resulting in a shortened testing time.

Source :
1. Jakim: Golden Churn butter non-halal
2. S. Unajak, P. Meesawat, K. Anyamaneeratch, D. Anuwareepong, K. Srikulnath, K. Choowongkomon (2011) Identification of species (meat and blood samples) using nested-PCR analysis of mitochondrial DNA. African Journal of Biotechnology. Vol. 10(29), pp. 5670-5676

Click here, then click on .

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On the results page, click on to verify the specificity of the selected probe sequence.

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Results generated show the number of matches to the probe accompanied by a list of matches. From the list of hits, the probe is demonstrated to match all types of Sus scrofa isolates and breeds.

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