The frozen drink industry has been developing rapidly in recent years. However, while the frozen drink market is expanding, some prominent problems such as microbial contamination have been exposed. Based on the results of recent food safety surveys on frozen drinks, the risk of microbial contamination of frozen drinks is analyzed in this paper, and some measures to prevent control microbial contamination are put forward based on the characteristics of the manufacturing process of frozen drinks. This article is expected to contribute to the improvement of the food safety level of frozen drinks in China.

An isotope internal standard coupled with gas chromatography-mass spectrometry (GC-MS) method was established for the simultaneous determination of four chloropropanol esters (3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, 1,3-dichloro-2-propanediol and 2,3-dichloro-2-propanol ester) in infant formula milk powder. Samples were dissolved and extracted withn-hexane, and then the extract was hydrolyzed by sodium methoxide in methanol, purified on a Florisil solid phase extraction column, derivatized with heptafluorobutyryl imidazole, detected by GC-MS in the single ion monitoring mode, and quantified by the internal standard method. Under the optimized conditions, all four chloropropanol esters showed good linearity in the range of 0.05–1.00 mg/L withR2 larger than 0.997. The detection limit of the method was 0.015 mg/kg. The mean recoveries at three spiked concentration levels (0.05, 0.10 and 0.50 mg/kg) were in the range of 85.9%–102.1% with relative standard deviations (RSDs,n = 6) ranging from 2.4% to 5.6%. The proposed method showed the advantages of high sensitivity, good clean-up efficiency and high accuracy, and it was suitable for the detection of chloropropanol esters in infant formula milk powder.

The lactoperoxidase–thiocyanate–hydrogen peroxide system is widely used as a feasible method for temporary preservation of raw milk in China. Nevertheless, due to its toxic and harmful nature, thiocyanate has been listed as an illegal food additive in raw milk and dairy products. In this study, various amounts of thiocyanate less than 10 mg/kg were found in 852 samples of dairy products marketed in China, of which 25.9% were less than 1 mg/kg and only 6.24% were 5–10 mg/kg. Furthermore, our analysis showed that the possible origin of thiocyanate might be raw milk but not illegal addition. Finally a risk assessment was performed on its potential health hazards.