Page 129 - BBLP ejournal2018.docx

Journal of Biotechnology in Livestock Production

Discussion

A molecular genetic method makes it possible to identify mt DNA of animal origin.There

were studies described the use of several mt DNA fragments such as cytochrome b genes

(Cheunsuk et al., 2012), ATP synthase subunits 6-8 (ATP6-8), 12s & 16s rDNA (Teletchea et al.,
2005), etc. PCR remains as sensitive, reliable, and rapid technique in detecting species-specific mt

DNA fragments (Kesmen et al., 2007).This study emphasized to develop a simple method for

simultaneous identification the composition of desired 6 different meat species in both raw and

cooked meat. Multiplex PCR testing, in which many primers are used in the same reaction, was

used in the study which the principle of species-specific primers would create different sizes of PCR

bands in the same reaction condition. In this study, the PCR reaction was able to share either the

same forward primer (goat, chicken, sheep, and pig) or reverse primer (buffalo and cattle) that was

helpful for setting an effective condition of the reaction (Table 1). The results indicated successful

amplification of the target cyt b genesequences with the expected amplicon sizes without fragment
produced by non-specific amplification (Figure 3). In Figure 4, the semi-quantitative analysis for

cattle and pig showed that the least concentration of pig’s DNA that could be detected when mixed
with cattle’s DNA was 0.5 ng or cattle to pig ratio at 1:0.025 v/v which similar to those of mixed DNA

between chicken and pig in Figure 5. These reactions had been performed in 3 replications to

ensure the efficacy of the test (data not shown) with similar results. These finding should be useful

for applying to food fraud detection. Thus, the study was designed a further test to detect the

commercial product components. The results showed that only some not all products contained

exactly animal meat as labeled. These products could not be able to determine by neither using

naked eye nor tasting according to the label. However, DNA analysis could be able to report the

true species regarding the listed sample products. In this study, only white pork sausage (sample

#2), pork sausage (sample #7), chicken sausage (sample # 8 and 9), and pork ball (sample # 10)
were matched with their labels while the others were not. Moreover, most products except sample

#7, 8, 9, 10 were collected from the food venders and local market which the origin of the products

were not identified. Due to the price of the raw materials, some producers might add other meat to

reduce the cost as well as the recipes of each food might either contain other animal parts such as

fat or contaminate during the process of cooking. However, the samples # 7, 8, and 9 were collected

from middle class supermarkets especially sample# 9 which indicated as a halal product showed

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