The milk fat globule membrane (MFGM) is a three-layered membrane that surrounds milk fat globules. Its main components include proteins, carbohydrates, and lipids, which are mainly derived from the mammary gland cell membrane. Different milk sources vary in the composition of MFGM proteins, which have good emulsifying properties, gastrointestinal stability and safety. Some MFGM proteins have diverse bioactivities including anti-inflammatory, antiviral and intestine regulatory effects and enhancing the exercise performance of muscles. This paper reviews the composition, physicochemical properties and bioactivities of MFGM proteins, which will provide a reference for the research and application of MFGM proteins in the dairy industry and related food additives.

A rapid detection method based on helicase-dependent isothermal DNA amplification (HDA) was established for Lactobacillus plantarum in fermented milk. Specific primers were designed according to the scrB gene sequence of Lactobacillus plantarum (Genbank Accession NO. AJ579541.1), and the optimal concentrations of UvrD helicase and T4 gp32 in the reaction system were determined through experiments. The limit of detection (LOD), specificity, consistency and stability of the proposed method were evaluated by use of L. plantarum-spiked samples, amplification of various strains, and electrophoresis of amplified products and sequence alignment analysis, respectively. The results showed that the optimized of UvrD helicase and T4 gp32 in the reaction system were found to be 0.15 and 5.0 μg, respectively. The HDA method had high specificity with no amplification of other strains tested. The detection limit was 2.8 × 101 CFU/g. The amplified product was consistent with the designed sequence length (273 bp) and the sequence homology was 100%. In conclusion: this method is rapid, simple, sensitive and suitable for the detection of Lactobacillus plantarum in fermented milk.

A quality control sample for the qualitative analysis of Listeria monocytogenes was developed by vacuum freezing drying technology, and the homogeneity and stability of the quality control sample were systematically analyzed. By optimizing the type of lyophilized matrix, the optimal conditions for the development of quality control samples were obtained. The homogeneity and stability of the developed quality control sample were verified by counting the number of cells as well as using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The quality control sample was white in color, spherical in shape and uniform in size. The results of cell counting for uniformity validation showed F = 0.567, which was less than the critical value, indicating good uniformity. In the transportation stability test, the quality control sample remained stable at 37 and 25 ℃. In the storage stability test, the resurrection rate of the quality control sample was 101.5% after 28 days of storage at ?20 ℃, and 99.6% after 28 days of storage at 4 ℃, indicating that the sample has good uniformity and stability, and can be used as a positive quality control sample for the detection and quality control of Listeria monocytogenes.

In order to evaluate the application value of ready-to-use Salmonella quality control samples in matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) identification of Salmonella in milk-containing formula foods for special medical purposes, this experiment evaluated the uniformity and stability of the quality control samples. After being stored at 20 ℃ for 0, 14 and 28 days, these samples were identified by mass spectrometry and the VITEK automatic microbial analysis system. The results showed that the quality control samples had good stability and uniformity, and their mass spectra were similar to each other. The VITEK system confirmed their identity as Salmonella. In conclusion, the ready-to-use Salmonella quality control strains can be used for the detection of Salmonella in milk-containing formula foods for special medical purposes.

A helicase-dependent isothermal DNA amplification (HDA) assay was developed for the rapid and accurate detection of Gluconacetobacter in yogurt.A pair of specific oligonucleotide primers according to the 16S ribosomal RNA gene (GenBank accession number:HQ677466.1) of Gluconacetobacter was designed,and the optimal concentration of UvrD helicase and T4 gp32 in the reaction system were determined.The HAD method enabled direct detection of Gluconacetobacter in yogurt.The specificity of the method was tested by amplification and electrophoresis of various strains in yoghurt using the HAD system.The amplification product by HDA was the same as the designed gene fragment (101 bp).The sensitivity of HDA was 102 CFU/g.The optimal reaction system was established by the use of 0.1 μg of UvrD helicase and 5.0 μg of T4 gp32.In conclusion,the method was sensitive and time saving.