The effects of Alcalase (AT), Protamex (PT) or Flavorzyme (FT) treatment on the antigenicity and molecular mass distribution of proteins, flavor and color of skim milk were investigated by using various techniques such as indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and Tricine-sodium dodecyl sulphate polyacrylamide gel electrophoresis (Tricine-SDS-PAGE). The results showed that the effect of AT treatment on reducing the antigenicity of the major milk allergens was significantly better than that of PT and FT treatment (P < 0.05). The antigenicity of α-lactalbumin (α-LA), β-lactoglobulin (β-LG) and casein (CN) was inhibited by 64.01%, 76.00% and 69.10% by AT treatment for 20 min at an enzyme/substrate ratio of 500 U/g, respectively. The amount of low molecular mass peptides in skim milk increased significantly after treatment with each of the three enzymes. The bitterness, astringency, aftertaste of bitterness (aftertaste-B) and aftertaste of astringency (aftertaste-A) increased with increasing enzymatic treatment time and with increasing enzyme/substrate ratio. The taste of FT-treated milk was better than that of AT- or PT-treated milk. The brightness value of milk decreased significantly, while the redness value increased significantly after enzymatic treatment (P < 0.05). The transmittance increased as well. The color of skim milk treated by AT was more similar to that of whole milk.

A new method for detecting five aflatoxin residues in raw milk was presented using micellar electrokinetic capillary chromatography with a diode array detector (MECC-DAD). The specificity of MECC-DAD was evaluated in comparison with that of high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). In the MECC-DAD method, samples were cleaned up by immunoaffinity column chromatography before separation on an uncoated fused-silica capillary column using 7.5 mmol/L borate buffer with 30 mmol/L sodium dodecyl sulfonate (pH 8.5) and 5% acetonitrile and the detection wavelength was set at 214 nm. In the HPLC-FLD method, samples were separated on a C18 column (150 mm × 4.6 mm, 5 μm) by gradient elution using a mobile phase consisting of acetonitrile and water after being cleaned up by immunoaffinity column chromatography. The analytes were detected by a fluorescence detector at 360 nm excitation wavelength and 440 nm emission wavelength. Results showed that MECC-DAD gave smoother and sharper peaks that were more symmetrical without tailing. The limits of detection of MECC-DAD and HPLC-FLD were 0.182–1.669 and 0.014–0.058 μg/L, both meeting the requirements for the determination of aflatoxin residues in raw milk. The precision of HPLC-FLD was somewhat higher than that of MECC-DAD. The recoveries of MECC-DAD and HPLC-FLD were 80.3%–137.0% and 79.6%–134.0%, respectively. When the two methods were applied to the same commercial milk samples, the P value for the deviation between the quantitative results obtained was 0.900, greater than 0.05, indicating no significant difference. In conclusion, MECC-DAD was simple, efficient and inexpensive, making it more suitable for the simultaneous determination of five aflatoxins in milk than HPLC-FLD.

The probiotic Lactobacillus plantarum LIP-1 was cultured in modified MRS medium at high cell density to investigate the effect of changes in medium components (the types and amounts of nitrogen source, carbon source and buffer salt, total amount of carbon and nitrogen, and carbon/nitrogen ratio) on the viable cell count and survival rate after freezedrying of this strain. The optimal medium was found to be composed of carbon source (sucrose) 33.35 g/L, nitrogen source (yeast powder, soy peptone and casein peptone, 3:3:5, m/m) 10.80 g/L, and buffer salt (sodium acetate, potassium dihydrogen phosphate and sodium citrate, 2.5:1:1, m/m) 14.85 g/L (namely 0.13 mol/L). The viable cell count of strain LIP-1 cultured in the optimized medium after freeze-drying was 9.767 (lg(CFU/mL)), which was distinctly higher than that cultured in MRS medium. The modified medium allowed high-cell-density fermentation of Lactobacillus plantarum LIP-1 while maintaining its viability during freeze-drying.

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.

A real-time (RT) optoelectronic microbiological assay for rapid detection of moulds and yeasts in yogurt was reported and validated by comparing its results with those obtained by applying the Chinese national standard method plate counting. Rapid detection of moulds and yeasts in commercialized yoghurt and spiked positive samples was successfully achieved by a semi-quantitative analytical procedure using the method, which makes it possible to pre-alert their presence or absence. The RT microbiological assay allowed detection of 10–3.5×105 CFU/mL of moulds and yeasts in 1.8–33 h. The time spent in this method for detecting microbial numbers below 10 CFU/mL as determined by conventional plate counting was over 33 h, without pre-alert during 48 h running. In addition, the results obtained closely agreed with those obtained by the plate counting method. The proposed method in this study provided a sensitive, simple and convenient approach for rapid screening of moulds and yeasts in yogurt in factories and laboratories and hence monitoring of critical control points.