Identification and characterization of microRNAs in raw milk during different periods of lactation, commercial fluid, and powdered milk products.
Recent baby formula milk powder contamination incidents have shown that the classic markers or standards in milk quality control are insufficient in identifying "manipulated" poor-quality milk. In the present study, we demonstrated for the first time that cow milk contains large amounts of microRNAs (miRNAs) and that the unique expression profile of milk-specific miRNAs can serve as a novel indicator and possible new standard for the quality control of raw milk and milk-related commercial products, such as fluid milk and powdered formula milk. First, using Solexa sequencing, we systematically screened miRNA expression in raw milk and identified a total of 245 miRNAs in raw milk. Unlike other classic biomarkers whose expression levels are nearly identical at different periods of lactation, individual miRNAs can be significantly altered during lactation process, implicating that miRNAs may be a more accurate indicator to reflect the quality alteration of milk. Second, using TaqMan probe-based miRNA quantitative RT-PCR, we further identified seven miRNAs that have a relatively consistent expression throughout the lactation process, and more importantly, the expression profile of these seven milk-specific miRNAs can serve as an ideal biomarker for discriminating poor-quality or "manipulated" milk from pure raw milk, as well as for the quality control of commercial milk products, such as fluid milk and powdered formula milk. Together, our findings provide a basis for understanding the physiological role of milk miRNAs and a new potential standard for determining the quality of raw milk or milk-related commercial products.
Chen
Xi
X
Jiangsu Diabetes Center, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093, China.
Gao
Chao
C
Li
Haijin
H
Huang
Lei
L
Sun
Qi
Q
Dong
Yanye
Y
Tian
Chunliang
C
Gao
Shengpu
S
Dong
Hailin
H
Guan
Danping
D
Hu
Xiaoyun
X
Zhao
Shujian
S
Li
Liang
L
Zhu
Lin
L
Yan
Qiao
Q
Zhang
Junfeng
J
Zen
Ke
K
Zhang
Chen-Yu
CY
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002417:Cattle; D005260:Female; D007774:Lactation / Q000235:genetics*; D035683:MicroRNAs / Q000032:analysis* / Q000378:metabolism; D008892:Milk / Q000378:metabolism* / Q000592:standards; D011786:Quality Control
D015415:Biomarkers; D035683:MicroRNAs