该研究对38个品牌的市售国内外羊奶粉进行了DNA提取和质量检测,采用普通聚合酶链式反应(polymerase chain reaction,PCR)和实时荧光定量PCR对羊奶粉中的牛源性成分进行定性和定量检测。结果表明,商品羊奶粉中DNA的OD值为1.3~1.5,质量浓度为200~500 ng/μL,其中纯羊奶粉DNA的纯度和质量浓度均显著高于配方羊奶粉(P＜0.05),DNA有不同程度的降解,PCR扩增效果明显,满足后续的掺假检测试验要求;普通PCR与实时荧光定量PCR均最低可检测到0.1%的牛源性成分,实时荧光定量PCR可对0.1%~50%的牛源性成分定量;对38种市售羊奶粉定性掺假检测得到有4种羊奶粉含有牛源性成分,与产品标签不相符,进一步定量结果发现其中3种羊奶粉中牛源性成分含量约为1%,1种羊奶粉中牛源性成分含量高于50%。因此,基于PCR技术的羊奶粉中牛源性成分的掺假检测方法可为羊奶粉标签声明的验证和产业品质控制提供可靠依据,保证市售羊奶粉产品的纯正性。
In order to help consumers understand the quality and safety of goat milk powder sold in China and abroad, and promote enterprises to improve the quality of goat milk powder, DNA extraction and quality testing were carried out on 38 brands of goat milk powder sold in China and abroad, and the bovine-derived components in goat milk powder were qualitatively and quantitatively detected by ordinary PCR and quantitative real-time PCR. The results showed that the OD value of DNA in commercial goat milk powder was 1.3-1.5 with a concentration of 200-500 ng/μL. The purity and concentration of DNA in pure goat milk powder were significantly higher than that of formula goat milk powder (P＜0.05). Moreover, DNA had different degrees of degradation, however the PCR amplification could meet the requirements of subsequent adulteration detection test. Both ordinary PCR and quantitative real-time PCR could detect at least 0.1% of bovine-derived components. The quantitative real-time PCR could quantify 0.1%-50% bovine-derived components in the samples. The qualitative adulteration test of 38 kinds of commercially available goat milk powder found that 4 kinds of goat milk powder could be detected bovine-derived ingredients, which were not consistent with the product label. Further quantitative results found that the content of bovine-derived ingredients in 3 kinds of goat milk powder was about 1%, and the content of bovine-derived ingredients in a kind of goat milk powder was higher than 50%. Therefore, PCR-based methods for the detection of adulterated bovine-derived components in goat milk powder, which could provide a reliable basis for the verification of goat milk powder label claims and industrial quality control, and it could also ensure the purity of commercially available goat milk powder products.
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