Determination of percent content of camel milk in adulterated milk samples by normalized real-time PCR system based on single-copy nuclear genes.

BACKGROUND Compared with the traditional qualitative polymerase chain reaction (PCR), which only identifies the category of species, the quantitative PCR method provides a value, which is very important for appropriate penalty enforcement according to the extent of adulteration. However, most of the currently quantitative PCR methods were based on mitochondrial genes, expressing different copy numbers in different cells and reducing the accuracy of quantitative results. In this study, the single-copy nuclear housekeeping genes, instead of multicopy mitochondrial genes, were selected as both the camel species-specific and the reference genes to develop a novel normalized PCR system. RESULTS This system had an excellent linear correlation (R2  = 0.9614) between the camel milk content and the Ct ratio (specific/reference genes), and allowed quantitative detecting percent content of camel milk in adulterated milk samples. The accuracy was effectively validated by simulated adulterated samples with the recoveries ranging from 90% to 120% and CV values <10%, exhibiting sufficient parameters of trueness and precision. CONCLUSION The normalized PCR system based on single-copy nuclear genes was a simple, rapid, and reliable method for the determination of percent content of camel milk in adulterated milk samples, and also provided a technical support for appropriate penalty enforcement. This article is protected by copyright. All rights reserved.

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