In this study, a prediction model based on Fourier transform mid-infrared spectroscopy was developed for the rapid detection of β-lactoglobulin in milk. The content of β-lactoglobulin in 260 different batches of milk samples was determined as reference by high performance liquid chromatography (HPLC), and the mid-infrared spectra of raw milk were collected using an Fourier transform mid-infrared spectrometer. The effective wavebands were selected, and the background noise was eliminated by Savitsky-Golay (SG) smoothing, first-order derivative or second-order derivative pretreatment before the establishment of the β-lactoglobulin prediction model by using partial least squares regression (PLSR). The results showed that SG five-point smoothing second-order derivative was the optimum preprocessing method. The PLSR model exhibited good prediction accuracy with correlation coefficient (R2) of 0.932 for the calibration set, root mean square error of calibration (RMSEC) of 0.049%, R2 of 0.923 for the calibration set, and root mean square error of prediction (RMSEP) of 0.057%.

Milk-derived extracellular vesicles (MEVs), originating from mammary epithelial cells, are nanoscale double-layered membrane vesicles transporting bioactive molecules like proteins, nucleic acids, and lipids, being crucial for intercellular communication and immune regulation. Although milk from minor animal species is not commonly found in the market due to its lower production, it possesses unique nutritional value and potential health benefits and is therefore worth exploring. This review covers the isolation and identification techniques, morphological characteristics, composition and biological characteristics of MEVs from goat, camel, yak, donkey, buffalo, porcine and horse milk. It points out the challenges and future directions in studying MEVs from minor dairy species, aiming to provide a theoretical foundation and scientific guidance for further research and application of MEVs so as to foster the development of the minor species milk industry.

Liquid chromatography-mass spectrometry was employed to determine the change of free amino acid contents in hard yak cheeses with different salt levels during 6 months of ripening. The results showed that a total of 23 free amino acids were detected, the major ones being aspartic acid, glutamic acid, isoleucine, leucine, phenylalanine, threonine and cysteine, together representing 94% to 95% of the total free amino acid content. The content of each free amino acid showed an increasing trend between months 1 and 6. In the late stage of maturation, the contents of threonine, asparaginate, aspartic acid, valine, proline and phenylalanine increased with increasing salt addition, the contents of alanine, histidine, arginine and tyrosine decreased, and the contents of leucine, isoleucine, serine, glycine and tryptophan first increased and then decreased. The contents of of glutamic acid, leucine, isoleucine, aromatic amino acid, cysteine, glycine and serine were significantly higher in long-ripened cheese with 1.3% salt addition than in those with higher salt contents. This study provides theoretical support for the development of low-salt hard yak cheese.

This study explored changes in the acidity of sheep milk across different lactation periods and the key factors affecting the acidity of sheep milk. The pH, titratable acidity, fat content, protein content and composition, total sugar content, mineral content, density, lactose content, fatty acid composition and content were analyzed, and the correlation between physicochemical indexes and acidity was investigated. The results indicated that the acidity of raw sheep milk was closely related to lactation stages. The highest acidity was observed in the early lactation period, which then gradually decreased as lactation progressed. Acidity changes were primarily associated with the protein content, fat content, fatty acid composition, total sugar content, lactose content, mineral content, and density of the milk. Among these, the protein content showed the strongest correlation with acidity changes, whereas fatty acid content had a relatively low correlation with acidity variations.

Organoids are derived from adult or pluripotent stem cells through in vitro differentiation, which can recapitulate the cellular diversity, spatial organization, and physiological functions of in vivo organs or tissues. Organoid models have been widely used in drug development, precision medicine and other fields, and have begun to be applied in the field of food safety. This paper briefly introduces the development history, classification and construction of organoids and their application in the metabolomics, nutritional and functional evaluation of milk and dairy products and research on their roles in intestinal protection. It also summarizes problems existing in the construction of organoid models and discusses future prospects for their application in milk and dairy products in order to provide a reference for further application of organoid models in various fields including food safety and nutrition.

Exosomes are extracellular vesicles (EVs) with a diameter of 30–150 nm. They are widely involved in intercellular communication and disease diagnosis, and can serve as drug delivery carriers for targeted disease treatment. Due to the lack of sufficient sources and methods to obtain exosomes, their therapeutic application as drug carriers is limited. Milk contains abundant exosomes. Multiple studies have shown that milk-derived exosomes play a crucial role in preventing and treating intestinal diseases. This article reviews the extraction and identification methods of milk-derived exosomes reported in the literature. It also discusses the role of milk-derived exosomes in regulating intestinal physiological functions by protecting the intestinal barrier, alleviating intestinal inflammation, regulating the intestinal microbiota, and promoting intestinal cell proliferation. Milk-derived exosomes have various advantages such as no adverse immune reactions or inflammatory reactions. Understanding the regulatory mechanism of milk-derived exosomes on intestinal physiological functions can help further study their role in preventing and treating intestinal diseases.

Pasteurization and ultra-high temperature treatment can kill most microorganisms in milk. However, since some bacteria such as Bacillus subtilis can resist pasteurization and ultra-high temperature treatments, even the most stringent heat treatments used to eliminate pathogenic microorganisms in the dairy industry cannot completely inactivate all microorganisms. In addition, highly heat-resistant spores can survive ultra-high temperature processing, so sterilized milk may be contaminated, causing bacterial spoilage in milk and dairy products during storage. In this review, the harms of Bacillus subtilis and its spores, spoilage-causing enzymes and biofilm to sterilized milk and the control measures for them are summarized so as to provide strategies for the prevention and control of Bacillus subtilis in sterilized milk and the quality assurance of milk and dairy products.

Microplastics (MPs) in food have aroused widespread concern, and it has been clarified that MPs have toxic effects on cells, animals and human organoids, and that the cytotoxicity is inversely proportional to the particle size of MPs, and positively proportional to the concentration of MPs and the time of exposure; in experimental animal models, the toxic effects of MPs mainly occur in the digestive, nervous, respiratory, reproductive, and cardiovascular systems; the hazardous effects of MPs have also been identified in the human organoids of liver, intestine, heart and brain. The contamination of MPs in dairy products may occur at different stages of the production process. This paper reviews the sources, toxicological effects and detection methods of MPs contamination in dairy products, with the aim of providing a reference for the risk prevention and control of MPs in dairy products and for future research.

Vanillin is a flavor widely used in the food industry. This paper discusses the application of vanillin in the food industry, worldwide limits for the use of vanillin, the characteristics of the production technology and the possible risks brought by vanillin for foods, and it also summarizes the methods for vanillin detection in dairy products, infant formulas and formulas for special medical purposes intended for infants including gas chromatography (GC), liquid chromatography (LC), gas chromatography-tandem mass spectrometry (GC-MS/MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and spectroscopy with special attention to their advantages and limitations. This review is expected to provide a basis for the detection and further research of vanillin in infant formulas for special medical purpose.

Aflatoxins (AFTs) is a group of secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus, which has stable physicochemical properties. Aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), aflatoxin M1 (AFM1), and aflatoxin M2 (AFM2) are the common analogues of AFT, with AFB1 being the most toxic and widespread one. The International Agency for Research on Cancer (IARC) under the World Health Organization has classified AFB1 as a Group 1 carcinogen. When cows eat contaminated feedstuffs such as peanut, corn, rice, soybean and wheat, some of the AFTs are converted in the body into AFM1, and AFM2, which can exist in milk and dairy products. This paper compares the difference between Chinese and international limits for AFTs in foods, and summarizes the methods for detecting aflatoxin in milk and dairy products such as thin-layer chromatography (TLC), mass spectrometry (MS), spectroscopy, electrochemistry, and rapid test strips. This paper analyzes the advantages and limitations of these methods and predicts future directions in the development of aflatoxin detection technology in milk and dairy products. It is hoped that this review will help in the development of a more convenient, specific, and sensitive detection method for aflatoxin in milk and dairy products.

A droplet digital polymerase chain reaction (ddPCR) method for the quantitative detection Acetobacter aceti in fermented milk was established. Specific primers and probes were designed according to the internally transcribed spacer (ITS) gene sequence of Acetobacter aceti, and annealing temperature was optimized. The specificity of the method was verified by applying it on various strains, the limit of detection (LOD) was determined for artificially inoculated Acetobacter aceti, and the absolute quantification was systematically investigated by comparing the results of ddPCR and the counting results. The experimental results showed that the optimal annealing temperature was 54.6 ℃, the method had strong specificity and high sensitivity, and the LOD was 7.2 × 101 CFU/mL. The quantitative deviation rate was 23.73%. This method can meet the demand for quantitative detection of Acetobacter aceti in fermented milk.

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.

The applicability of silver nitrate titration and potentiometric titration, two of the three detection methods for chlorine in food samples specified in the national standard GB 5009.44—2016, for infant formula for special medical purposes was evaluated. The results showed that the spiked recoveries of silver nitrate titration for partially hydrolyzed protein infant formula, extensively hydrolyzed protein infant formula, and amino acid-based infant formula for special medical purposes were 95%–108%, 98%–125% and 100%–106%, respectively, and the relative standard deviations (RSD) for precision were between 12.7% and 32.9%. The results of potentiometric titration was lower than that of silver nitrate titration.

This research investigated the effects of reconstitution pH value and temperature, storage duration, sunlight exposure and reheating on the contents of vitamin B1 and vitamin D in six different kinds of formula foods for special medical purposes sold on the market. The results showed that the vitamin B1 content decreased with increasing reconstitution pH value and temperature and storage time, but was little affected by reheating. The vitamin D content decreased with storage time in sunlight. pH value and reheating had little effect on the content of vitamin D. The optimum conditions for ensuring the highest utilization ratio of vitamin B1 and vitamin D in formula foods for special medical purposes were reconstitution in acidic water (pH < 7) at 40–60 ℃, storage in darkness and preferably use immediately after reconstitution.

Bioactive peptides were prepared from sheep casein by neutral protease hydrolysis. The effect of hydrolysis time on the degree of hydrolysis and angiotensin converting enzyme (ACE) inhibitory activity of hydrolsates was investigated. The peptides were analyzed and identified by liquid chromatography-mass spectrometry (LC-MS) to select the ones with potential ACE inhibitory activity. The results showed that the highest degree of hydrolysis of 9.65% as well as a percentage of ACE inhibition of 84.55% was attained after 300 min, and the concentration of the peptide YYQQRP required for 50% ACE inhibition was 5–10 μmol/L. The sequence analysis of the peptides was performed by ultra-high pressure liquid chromatography-time of flight mass spectrometry (UPLC-TOF-MS). YYQQRP was identified as a new peptide with potential ACE inhibitory activity by comparison with the protein database. It was hypothesized that the structure of YYQQRP might be similar to that of the substrate and could reduce the catalytic activity of ACE by binding to the active site of ACE.

Molecular biology studies have confirmed that bioactive polysaccharides are naturally occurring polymers that have a variety of physiological and biochemical functions. The water-complexing ability, high viscosity, antioxidant and anti-aging properties of bioactive polysaccharides lay the foundation for their application in the fields of food, and the use of bioactive polysaccharides as a bioactive ingredient in functional foods has become a current research focus. Fermented milk has good flavor and probiotic properties, but it also has the disadvantages of short shelf life, poor curd quality, and general probiotic performance. How to improve the quality of fermented milk is a current major challenge. This article focuses on recent progress in the application of different types of bioactive polysaccharides in fermented milk, and reviews the effects and mechanisms of action of bioactive polysaccharides on the physicochemical, gel and probiotic properties of fermented milk. Furthermore, it discusses future prospects for the application of bioactive polysaccharides in fermented milk. This review is expected to provide a reference for exploring the functions of bioactive polysaccharides and improving the quality of fermented milk.

Aptamer technology is a new detection technology which has been widely used in the field of animal-origin food safety detection because of its specificity, high affinity, rapidity and low cost. In this paper, we describe the principle and classification of aptamer screening technologies, and we review recent progress in their applications in the detection of food additives, veterinary drug, hormone and antibiotic residues, mycotoxins, and pathogenic bacteria in milk and dairy products.

As a nutritional supplement for people with special needs, the food for special medical purposes (FSMP) has occupied an important position in the global market. As the main source of added nutritional components in FSMP, nutritional fortifiers are of great significance to improve its quality. This paper focuses on the comparative analysis of the standards and regulations of the Codex Alimentarius Commission (CAC), the EU and China on nutrients and nutritional fortifiers in FSMP with respect to limits, ingredients, sources, and so forth, in order to provide useful information for improving the standards for the use of nutritional fortifiers in FSMP in China.

A rapid method using helicase-dependent isothermal DNA amplification (HDA) for the detection of Gluconobacter in fermented milk was established. The ITS gene sequence (gene number KF896260.1) of Gluconobacter was selected as the target gene for design of specific primers, and the concentrations of UvrD helicase and T4 gp32 in the reaction system were optimized to establish an optimal reaction system. The HDA method was used to directly detect Gluconobacter in fermented milk. The established HDA system was used to amplify and electrophoretically detect various strains in fermented milk to verify the specificity of the method and determine its detection limit. The results showed that the detection of Gluconobacter in fermented milk by the HDA method was consistent with the designed sequence length (309 bp) and the detection limit was 4.3 × 101 CFU/g. The appropriate amounts of UvrD helicase and T4 gp32 added in the reaction system were 0.1 and 5.0 μg, respectively. The method is highly sensitive and time saving.

An analytical method for the determination of 4 steroid hormones in milk and milk power was developed by filtration solid phase extraction combined with ultra performance liquid chromatography-tandem mass spectrometry. Samples were extracted with acetonitrile, and purified on a PRiME HLB cartridge. Then the chromatographic separation was achieved using an Acquity BEH C18 column (2.1 mm × 100 mm, 2.5 μm) with a mobile phase consisting of water and acetonitrile. The compounds were ionized using an electrospray ionization source in the negative ion mode and quantitated by the internal standard method. The results showed that the calibration curves of all analytes had a good linear relationship in the concentration range of 0.2–100.0 ng/mL. The limits of detection and limits of quantitation were 0.4–2.0 and 0.8–4.0 μg/kg, respectively. The recoveries of the method were in range of 87.7%–110.8% with relative standard deviations (RSDs) of 0.85%–4.56% in milk and in range of 89.2%–107.4% with RSDs of 0.85%–4.56% in milk power. This method was proved to be rapid, sensitive, and useful for the quantification of 4 steroid hormones in milk and milk power samples.

This study investigated the optimization of formulations for dairy beverage supplemented with an extruded mixture of Tremella funciformis and five grains using one-factor-at-a-time and orthogonal array design methods. The sensory evaluation score and stability of the beverage were evaluated as a function of the amount of the extruded product, sieve mesh size used on the powdered extrudate and the amount of the composite stabilizer. Changes in the rheological properties and particle size distribution of the beverage during 7 days of storage at 4, 25 and 37 ℃ were measured by a rheometer and a particle size analyzer, respectively. The optimum process conditions were determined as follows: adding extrudate at 5% and the composite stabilizer at 0.4% and sieving the extrudate through a 160-mesh sieve. The sensory evaluation score and stability of the beverage produced under the optimized conditions were (90.14 ± 0.32) points and (92.27 ± 0.07)%, respectively. After storage at 4, 25 and 37 ℃, the beverage was characterized as a pseudoplastic fluid in static rheology and as a weak gel in dynamic rheology. After storage at 4 ℃, the viscosity coefficient and particle size distribution were similar to those before storage. To maintain its taste and shelf life (up to 180 days), the beverage should be stored at 4 ℃, and cold chain distribution is recommended for it.

As a representative healthy food, dairy products have always been favored by consumers. The nutritional and health properties of dairy products can be improved by incorporating cereals, not only enhancing the popularity of dairy products for consumption as staple foods and the development of functional dairy products, but also promoting the diversified and healthy development of the dairy processing industry. This article reviews the application of cereals in dairy products with a focus on technical aspects, the stability of dairy products containing cereals, the impact of cereal ingredients and processing conditions on the product quality, structural system and processing properties, and it summarizes the past and present status of research on dairy products containing cereals. This review hopes to provide detailed information to promote the development of dairy products containing cereals and to popularize their consumption as staple foods.

Tea polyphenols, secondary metabolites found in green tea, are widely used in the food and medicinal industries because of their antioxidant and anti-cancer activity and preventive effect against cardiovascular diseases. The interaction of tea polyphenols with milk proteins can alter the structure of milk proteins and further affect the functional properties and bioavailability of dairy products. There have been widespread concerns about the binding of phenolic compounds to milk proteins due to the special structures of milk proteins. This review describes the mechanism of polyphenol-milk protein interaction, the factors influencing this interaction, the characteristics of reaction products, the methods used to analyze the mechanism, and the effects of this interaction on the functional properties and bioavailability of dairy products. Through this review, we aim to lay a theoretical basis for the development of new products based on the combination of tea polyphenols and milk proteins.

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of vancomycin, norvancomycin and teicoplanin in milk samples. Selective reaction monitoring was performed and the external standard method was used for quantification. Among various solvents tested, 0.1% formic acid-acetonitrile (85:15, V/V) was selected. Samples were ultrasonically extracted and vancomycin and norvancomycin were cleaned up by cation exchange column chromatography, while teicoplanin was purified using a C18 solid-phase extraction (SPE) cartridge. Acetonitrile-0.1% formic acid solution was chosen as mobile phase for gradient elution. The analytes were separated on a reversed-phase C18 column before being analyzed by mass spectrometry. The limits of detection (LOD) for vancomycin, norvancomycin and teicoplanin were 2, 1 and 2 μg/kg, and the limits of quantitation (LOQ) were 4, 2 and 4 μg/kg, respectively. The recoveries of the method ranged from 77.3% to 84.5% at spiked levels equal to LOQ, 5 × LOQ and 10 × LOQ, with relative standard deviations (RSD) of 4.7%–7.2%. The method could be used in the qualitative and quantitative detection of vancomycin, norvancomycin and teicoplanin in milk samples.

Fresh Pleurotus nebrodensis was homogenized for use as an ingredient in the formulation of milk beverage. The effect of homogenization time on the particle size distribution of mushroom homogenate was investigated by a laser particle size analyzer. The formulation was optimized using response surface methodology. The independent variables were concentration and particle size of Pleurotus nebrodensis homogenate, composite stabilizer and skim milk powder. The stability of beverage was used as response variable. The composite stabilizer consisted of pectin, carboxy methyl cellulose (CMC) and monoglyceride with a ratio of 1.0:1.3:1.7 (m/m). Incorporation of 8% mushroom homogenate passing through a 100-mesh sieve, 0.3% composite stabilizer and 9% skim milk powder gave a homogenous product with a moderate sour and sweet taste and the best stability of (89.20 ± 0.41)%. Particle size analysis showed that the mean particle size of the beverage was (46.30 ± 0.51) μm and the particle size distribution was as follows: D (10)=11.78 μm, D (50) = 28.70 μm, and D (90) = 108.80 μm, which was significantly different from that of three commercial milk beverages. This beverage contained more protein ((2.46 ± 0.12)%) than commercial beverages and met the requirement of the national standard for milk beverage (GB/T 21732?2008). The beverage displayed both irregular particles and regular spherical particles with uniform size distribution and without particle aggregation as observed under microscopy and its particle size distribution was similar to that of commercial beverages.

In this paper, Cr (Ⅲ) and Cr (Ⅵ) in milk were determined by high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). A PRP-X100 cation exchange column was used. The influence of mobile phase concentration, pH value and flow rate on the degree of separation and retention time was investigated. The mobile phase selected was NH4NO3solution (0.10 mol/L, pH 7) at a flow rate of 1.0 mL/min. Under the optimized conditions, the mass spectrometric and ion interferences were eliminated by using the natural abundance ratio of 52Cr to 53Cr as reference value, and the retention time of Cr (Ⅲ) and Cr (Ⅵ) were determined to be 2.227 and 1.856 min, respectively. Good linearity was observed for Cr (Ⅲ) and Cr (Ⅵ) with correlation coefficients of 0.999 5 and 0.999 7, respectively. The detection limits were 0.015 and 0.016 μg/L, respectively. The overall recoveries for the two valence states were in range of 71.52% to 90.27%. This method proved to be useful for simultaneous analysis of different Cr valence states in milk and dairy products.

Fermented okara with good processing suitability containing 13.4% soluble dietary fiber (SDF) was homogenized with a blender. After addition of other ingredients, the homogenate was formulated to produce a healthy high SDF milk beverage that was uniform and tasted good. Using one-factor-at-a-time method and response surface methodology, the optimum homogenization conditions were determined as follows: blender treatment time 15 min, blender rotation rate 10 000 r/min, stabilizer mixture 0.2%, temperature 45 ℃, pressure 30 MPa, and homogenization time 120 s, and the optimum combination of ingredients was fermented okara 7% (particles sieved through 60 mesh), white sugar 6%, and milk powder 9%. The milk beverage prepared under the optimized conditions had a good particle size distribution. Its soluble solids content was 11%, stability coefficient 0.8 and centrifugal sedimentation rate 2.3%. The product was milky white, and it was a uniform system with good taste and good stability.

High-quality cheese bread rich in nutrients can be made by adding cheese to bread. The effect of cheese addition on dough hardness as well as texture and staling properties and major nutrients of bread was analyzed in this study. The formulation was optimized using one-factor-at-a-time and orthogonal array methods. Dough hardness and sensory scores of bread were considered as response variables. The optimum combination obtained were cheese 15%, dry yeast 1.5% and bread improver 0.8%. The cheese bread made using the optimized formulation by the direct leavening method had a delicate taste and soft texture with rich cheese flavor. Moreover, the dough hardness was 94.317 g, the bread hardness was 402.255 g, the sensory score was 92, and the protein content was 14.5 g/100 g. The cheese bread had better quality and was more resistant to staling than ordinary bread.

Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) were compared for determining the contents of metal elements in infant formula milk powder. The limits of detection (LOD) and quantitation (LOQ) of ICP-MS were established using Sc, Rh and Bi as internal standards. Relative standard deviations (RSDs) for 26 analytes were less than 5.0%, and recoveries from spiked samples were 82.80%-110.80%. Eight metal elements could be simultaneously determined by ICP-AES, whose LOD and LOQ were slightly higher than those of ICP-MS. Furthermore, ICP-AES exhibited a good linearity and spiked recoveries in the range of 91.64%-112.73%. In the end, we concluded that both ICP-MS and ICP-AES had a high precision and a good linearity, but ICP-MS allowed the determination of a wider range of metal elements with lower LOD and LOQ.