In order to better analyze the quality and predict the shelf life of yogurt, changes in the number of lactic acid bacteria, pH value and acidity in yogurt at different storage temperatures were analyzed, and the temperature dependence and shelf life of yogurt were studied by the combined use of kinetic analysis and the Arrhenius equation. The results showed that the number of lactic acid bacteria was maintained, and the decrease of pH value and the increase of acidity value were slowed down during storage at 9 ℃. The acidity value could well reflect the quality changes of yogurt, and the activation energy of yogurt was 67.5 kJ/mol as determined by chemical kinetics. Furthermore, a shelf-life model based on the acidity of yogurt was obtained.

A rapid method for the determination of vitamin B2 in infant formula milk powder by high performance liquid chromatography (HPLC) was developed. Vitamin B2 was extracted by ultrasonic treatment with water, and the protein in the extract was removed by precipitation with zinc acetate and potassium ferrocyanide. The analysis was performed on a C18 column using 0.05 mol/L sodium acetate:methanol (70∶30, V/V) as the mobile phase. The limit of detection of the proposed method was 0.2 mg/kg, and a linear calibration curve was obtained in the range of 0.01 to 1.0 μg/mL. Recoveries of spiked samples were between 80.4% and 87.2%. The results indicated that this method was quick and convenient and could be used to detect vitamin B2 in infant formula milk powder.

Food traceability is more and more important in the food safety, and as a potentially effective tool in the food traceability, DNA barcode is developing rapidly in recent years. This review describes the applications of DNA barcode in food safety especially in food traceability. From the concept of DNA barcode to food test, food traceability and prevent commercial fraud in food. DNA barcode can ensure food safety and prevent commercial fraud, but to the large-scale applications, there is still a long way to go.