Addressing flavor challenges in reduced-fat dairy products: A review from the perspective of flavor compounds and their improvement strategies.

In recent years, the demand for reduced-fat dairy products (RFDPs) has increased rapidly as the health risks associated with high-fat diets have become increasingly apparent. Unfortunately, lowering the fat content in dairy products would reduce the flavor perception of fat. Fat-derived flavor compounds are the main contributor to appealing flavor among dairy products. However, the contribution of fat-derived flavor compounds remains underappreciated among the flavor improvement factors of RFDPs. Therefore, this review aims to summarize the flavor perception mechanism of fat and the profile of fat-derived flavor compounds in dairy products. Furthermore, the characteristics and influencing factors of flavor compound release are discussed. Based on the role of these flavor compounds, this review analyzed the current and potential flavor improvement strategies for RFDPs, including physical processing, lipolysis, microbial applications, and fat replacement. Overall, promoting the synthesis of milk fat characteristic flavor compounds in RFDPs and aligning the release properties of flavor compounds from the RFDPs with those of equivalent full-fat dairy products are two core strategies to improve the flavor of reduced-fat dairy products. In the future, better modulation of the behavior of flavor compounds by various methods is promising to replicate the flavor properties of fat in RFDPs and meet consumer sensory demands.

Double-Tube Multiplex TaqMan Real-Time PCR for the Detection of Eight Animal-Derived Dairy Ingredients.

Milk and dairy products represent important sources of nutrition in our daily lives. The identification of species within dairy products holds importance for monitoring food adulteration and ensuring traceability. This study presented a method that integrated double-tube and duplex real-time polymerase chain reaction (PCR) with multiplex TaqMan probes to enable the high-throughput detection of animal-derived ingredients in milk and dairy products. The detection system utilized one pair of universal primers, two pairs of specific primers, and eight animal-derived specific probes for cow, buffalo, goat, sheep, camel, yak, horse, and donkey. These components were optimized within a double-tube and four-probe PCR multiplex system. The developed double-tube detection system could simultaneously identify the above eight targets with a detection limit of 10-0.1 pg/µL. Validation using simulated adulterated milk samples demonstrated a detection limit of 0.1%. The primary advantage of this method lies in the simplification of the multiplex quantitative real-time PCR (qPCR) system through the use of universal primers. This method provides an efficient approach for detecting ingredients in dairy products, providing powerful technical support for market supervision.

State-of-the-art nanosensors and kits for the detection of antibiotic residues in milk and dairy products.

Antibiotic resistance is increasingly seen as a future concern, but antibiotics are still commonly used in animals, leading to their accumulation in humans through the food chain and posing health risks. The development of nanomaterials has opened up possibilities for creating new sensing strategies to detect antibiotic residues, resulting in the emergence of innovative nanobiosensors with different benefits like rapidity, simplicity, accuracy, sensitivity, specificity, and precision. Therefore, this comprehensive review provides pertinent and current insights into nanomaterials-based electrochemical/optical sensors for the detection of antibitic residues (ANBr) across milk and dairy products. Here, we first discuss the commonly used ANBs in real products, the significance of ANBr, and also their binding/biological properties. Then, we provide an overview of the role of using different nanomaterials on the development of advanced nanobiosensors like fluorescence-based, colorimetric, surface-enhanced Raman scattering, surface plasmon resonance, and several important electrochemical nanobiosensors relying on different kinds of electrodes. The enhancement of ANB electrochemical behavior for detection is also outlined, along with a concise overview of the utilization of (bio)recognition units. Ultimately, this paper offers a perspective on the future concepts of this research field and commercialized nanomaterial-based sensors to help upgrade the sensing techniques for ANBr in dairy products.

Market-driven fortification of vitamins and minerals in packaged foods targeted at children in Brazil.

This study aimed to characterise the market-driven fortification of vitamins and minerals in packaged foods targeted at children in Brazil. We analysed 535 food labels using data collected in a census-type method (n = 5620) of food labels in a Brazilian supermarket in 2013. Micronutrients declared in nutrition claims and the ingredients list (synthetic compounds) were considered to be added for commercial purposes. Analysis of the ingredients list and nutrition claims showed that market-driven fortification of vitamins and minerals was present in 27.1% of foods. The main vitamins and minerals were vitamins A, B complex, C, D, calcium, iron and zinc. The food groups 'Milk and dairy products' and 'Sugars, sugary foods and snacks' had the highest frequencies of micronutrients declared in the ingredients list. Calcium, iron, phosphorus, zinc and all vitamins, except B7, were found to be added for commercial purposes. Micronutrients were found to be commonly added to packaged foods as a marketing strategy directed at parents and their children. Future studies should assess the amount of vitamins and minerals added to packaged foods targeted at children and whether intakes of vitamins and minerals in children are potentially excessive.

Cholesterol and Its Oxidation Derivatives Content in Market Dairy Products.

Cholesterol oxidation products (COPs) are contaminants of food of animal origin. Increased levels of these compounds in the human body are associated with an increased risk of many non-communicable diseases. Dairy products are mentioned among the main sources of these compounds in the diet. The objective of this study was to evaluate the contents of cholesterol and its oxidized derivatives in eleven groups of dairy products, willingly consumed in European countries. The levels of COPs were determined by applying the GC-TOF/MS method. In the tested products, cholesterol and its oxidation derivatives, such as 7-ketocholesterol, 7α-hydroxycholesterol, 7ß-hydroxycholesterol, 5,6ß-epoxycholesterol and 5,6α-epoxycholesterol, were determined. The studied dairy products differed in their contents and profiles of oxysterols. The highest contents of COPs were found in cheese with internal mold (13.8 ± 2.5 mg kg-1) and Cheddar (11.7 ± 3.5 mg kg-1), while the lowest levels were detected in yoghurt (0.94 ± 0.30 mg kg-1) and kefir (0.57 ± 0.11 mg kg-1). 7-ketocholesterol and 5,6ß-epoxycholesterol were the dominant oxysterols. The ratio of oxidized derivatives to total cholesterol was on average 1.7%. Our results confirmed that dairy products are an important dietary source of COPs. Their levels should be monitored in dairy products to provide the best health quality.

Contamination of dairy products with tris(2,4-di-tert-butylphenyl) phosphite and implications for human exposure.

Tris(2,4-di-tert-butylphenyl) phosphite (AO168), an organophosphite antioxidant, can be oxidized to tris(2,4-di-tert-butylphenyl) phosphate (AO168 = O) during the production, processing, and application of plastics. AO168 = O can be further transformed to bis(2,4-di-tert-butylphenyl) phosphate and 2,4-di-tert-butylphenol. Here, we discovered the contamination of AO168 and its transformation products in dairy products for the first time. More samples contained AO168 (mean concentration: 8.78 ng/g wet weight [ww]), bis(2,4-di-tert-butylphenyl) phosphate (mean:11.1 ng/g ww) and 2,4-di-tert-butylphenol (mean: 46.8 ng/g ww) than AO168 = O (mean: 40.2 ng/g ww). The concentrations of AO168 and its transformation products were significantly correlated, and differed with the packaging material and storage conditions of the product. Estimated daily intakes (EDIs) of AO168 and its transformation products were calculated. Although the overall dietary risks were below one, transformation products accounted for 96.7% of the total hazard quotients. The high-exposure EDIs of total AO168 were above the threshold of toxicological concern (300 ng/kg bw/day), and deserve continual monitoring.

An instrument-free, integrated micro-platform for rapid and multiplexed detection of dairy adulteration in resource-limited environments.

In dairy industry, expensive yak's milk, camel's milk, and other specialty dairy products are often adulterated with low-cost cow's milk, goat's milk and so on. Currently, the detection of specialty dairy products typically requires laboratory settings and relies on skilled operators. Therefore, there is an urgent need to develop a multi-detection technology and on-site rapid detection technique to enhance the efficiency and accuracy of the detection of specialty dairy products. In this study, we introduced a fully integrated and portable microfluidic detection platform called Sector Self-Driving Microfluidics (SDM), designed to simultaneously detect eight common species-specific components in milk. SDM integrated nucleic acid extraction, purification, loop-mediated isothermal amplification (LAMP), and lateral flow strip (LFS) detection functions into a closed microfluidic system, enabling contamination-free visual detection. The SDM platform used a constant-temperature heating plate, powered by a mobile battery, eliminated the need for additional power support. The SDM platform achieved nucleic acid enrichment and transfer through magnetic force and liquid flow driven by capillary forces, operating without external pumps. The standalone SDM platform could detect dairy components with as low as 1% content within 1 h. Validation with 35 commercially available samples demonstrated 100% specificity and accuracy compared to the gold standard real-time PCR. The SDM platform provided the dairy industry with an efficient, convenient, and accurate detection tool, enabling rapid on-site testing at production facilities or sales points. This facilitated real-time monitoring of quality issues during the production process, quickly identifying potential risks and preventing substandard products from entering the market.

Microfluidic paper-based analysis device applying black phosphorus nanosheets@MWCNTs-COOH: A portable and efficient strategy for detection of ß-Lactoglobulin in dairy products.

This study prepared a novel, portable and cost-effective microfluidic paper-based electrochemical analysis device (µ-PAD) using black phosphorus nanosheets@carboxylated multi-walled carbon nanotubes (BPNSs@MWCNTs-COOH) nanocomposites for ß-lactoglobulin (ß-LG) detection. At the appreciate ratio, the synthesized BPNSs@MWCNTs-COOH was demonstrated to not only serve as a high-quality substrate for the specific aptamer immobilization, but also improve the electron transfer capability of the sensing interface. The µ-PADs, utilizing BPNSs@MWCNTs-COOH and aptamer recognition, exhibited a wider detection range (10-1000 ng mL-1) and lower detection limit (LOD: 0.12 ng mL-1) for ß-LG, and demonstrated enhanced specificity, satisfactory anti-interference ability and stability. When applied to the ß-LG determination in dairy samples, the µ-PAD yielded ß-LG concentrations highly correlated with those obtained using the HPLC method (R2: 0.9982). These results emphasized the reliable performance of the developed µ-PADs in ß-LG allergen quantification, highlighting their potential as an efficient platform for the rapid screening of ß-LG allergens.

Evaluation of a novel stationary phase for the separation of lactose and isomers in lactose-free products using high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD).

Lactose intolerance is a widespread condition, which prevents a large number of people from consuming dairy products as a part of their daily diet. It is estimated that an average of 65% of the global population is suffering from lactose intolerance. The global market for 'lactose-free' dairy products is rapidly growing and the criteria for 'lactose-free' labelled products are becoming stricter. To check the lactose contents in these products there is a need for fast, sensitive, and selective analytical method. A method is presented for fast and sensitive determination of lactose and its isomers using High-Performance Anion Exchange Chromatography in combination with Pulsed Amperometric Detection (HPAEC-PAD). The use of a new anion-exchange column, SweetSep™ AEX200, which is a strong anion-exchange column with highly monodisperse 5 µm particles, allowed the separation of all compounds of interest in less than 8 min with high resolution. A variety of dairy products were analyzed to demonstrate the versatility of the method.

Microwave vacuum drying of dairy cream: Processing, reconstitution, and whipping properties of a novel dairy product.

Traditional ways to preserve cream involve processing it into butter, butter oil, or frozen storage. These technologies do not preserve the unique functionality of cream with respect to whipping or processing into butter. In this work, microwave vacuum drying (MVD) was investigated as a method to manufacture dehydrated cream. Dehydrated cream microstructure, color, and free fat were evaluated using scanning electron microscopy, colorimetry, and solvent extraction, respectively. Effects of homogenization on reconstituted cream microstructure and functionality were investigated using confocal laser scanning microscopy, color, particle sizing, and texture analysis of whipped cream. Reconstituted MVD cream whipped faster, and the whipped cream was more cohesive and firmer when 2-step homogenization at 3.5/7 MPa was used. Fat globules in reconstituted MVD cream were covered by phospholipids, explaining MVD cream's similar functionality compared with pasteurized cream. These results may foster the development of novel shelf stable and highly functional dairy products using MVD.

Antibiotic residues in milk and dairy products in China: occurrence and human health concerns.

Although veterinary antibiotics are essential in preventing and treating clinical diseases in cattle, the frequent use of antibiotics leads to antibiotic residues in milk and dairy products, consequently threatening human health. The massive milk consumption makes it necessary to assess antibiotic pollution and health impact comprehensively. Hence, we conducted a systematic review to evaluate antibiotics in milk and dairy products and their potential health risk. We searched four databases using multiple keyword combinations to retrieve 1582 pieces of literature and finally included eighteen articles to analyze antibiotic residues in milk and dairy products. These studies detected seven antibiotics in different regions of China. Quinolones and ß-lactam antibiotics exceeded the MRL for raw and commercial milk. The maximum levels of sulfonamides and tetracyclines were detected in the same raw milk sample, exceeding the MRL. The estimated THQ and HI values in milk and dairy products are less than 1 for adults, indicating negligible noncarcinogenic health risk of antibiotics through consuming milk and dairy products. Children face higher health risks than adults, with the HI and THQ of quinolones exceeding 1. It is worth noting that quinolones accounted for nearly 89% of health risks associated with all antibiotics. Finally, we put forward possible research directions in the future, such as specific health effects of total dietary exposure to low levels of antibiotics. In addition, policymakers should effectively improve this problem from the perspectives of antibiotic use supervision, antibiotic residue analysis in food, and continuous environmental monitoring and control.

Dairy consumption and incident prediabetes: prospective associations and network models in the large population-based Lifelines Study.

BACKGROUND: Evidence on associations between dairy consumption and incident prediabetes is inconsistent. One potential explanation for heterogeneity is that health behavior and food intake covary with the consumption of various high-fat and low-fat dairy types. OBJECTIVE: The objective was to investigate the associations of total dairy and dairy types with incident prediabetes and to assess how dairy intake is linked with metabolic risk factors, lifestyle behaviors, and foods, as potential explanations for these associations. METHODS: Overall, 74,132 participants from the prospective population-based Lifelines study were included (mean age, 45.5 ± 12.3 y; 59.7% female). Baseline dairy intake was measured using a validated food frequency questionnaire. Prediabetes at follow-up was defined based on the World Health Organization/International Expert Committee criteria as fasting plasma glucose of 110-125 mg/dL or glycated hemoglobin concentrations of 6.0%-6.5%. Associations were analyzed using Poisson regression models adjusted for social demographics, lifestyle behaviors, family history of diabetes, and food group intake. Interconnections were assessed with mixed graphical model networks. RESULTS: At a mean follow-up of 4.1 ± 1.1 y, 2746 participants developed prediabetes (3.7%). In regression analyses, neutral associations were found for most dairy types. Intake of plain milk and low-fat milk were associated with a higher risk of prediabetes in the top compared with bottom quartiles (relative risk [RR]: 1.17; 95% confidence interval [CI]: 1.05, 1.30; P-trend = 0.04 and RR: 1.18; 95% CI: 1.06, 1.31; P-trend =0.01). Strong but nonsignificant effect estimates for high-fat yogurt in relation to prediabetes were found (RRservings/day: 0.80; 95% CI: 0.64, 1.01). The network analysis showed that low-fat milk clustered with energy-dense foods, including bread, meat, and high-fat cheese, whereas high-fat yogurt had no clear link with lifestyle risk factors and food intake. CONCLUSIONS: In this large cohort of Dutch adults, low-fat milk intake was associated with higher prediabetes risk. Heterogeneous associations by dairy type and fat content might partly be attributed to confounding caused by behaviors and food intake related to dairy intake.

Effect of Isoenergetic Substitution of Cheese with Other Dairy Products on Blood Lipid Markers in the Fasted and Postprandial State: An Updated and Extended Systematic Review and Meta-Analysis of Randomized Controlled Trials in Adults.

Consumption of fat as part of a cheese matrix may differentially affect blood lipid responses when compared with other dairy foods. This systematic review was conducted to compare the impact of consuming equal amounts of fat from cheese and other dairy products on blood lipid markers in the fasted and postprandial state. Searches of PubMed (Medline), Cochrane Central and Embase databases were conducted up to mid-June 2022. Eligible human randomized controlled trials (RCTs) investigated the effect of isoenergetic substitution of hard or semi-hard cheese with other dairy products on blood lipid markers. Risk of bias (RoB) was assessed using the Cochrane RoB 2.0 tool. Random-effects meta-analyses assessed the effect of ≥2 similar dietary replacements on the same blood lipid marker. Of 1491 identified citations, 10 articles were included (RoB: all some concerns). Pooled analyses of 7 RCTs showed a reduction in fasting total cholesterol, LDL-C and HDL-C concentrations after ≥14 d mean daily intake of 135 g cheese (weighted mean difference [WMD]: -0.24 mmol/L; 95% confidence interval (CI): -0.34, -0.15; I2 = 59.8%, WMD: -0.19 mmol/L; 95% CI: -0.27, -0.12; I2 = 42.8%, and WMD: -0.04 mmol/L; 95% CI: -0.08, -0.00; I2 = 58.6%, respectively) relative to ∼52 g/d butter. We found no evidence of a benefit from replacing cheese for ≥14 d with milk on fasting blood lipid markers (n = 2). Limited postprandial RCTs, described in narrative syntheses, suggested that cheese-rich meals may induce differential fed-state lipid responses compared with some other dairy matrix structures, but not butter (n ≤ 2). In conclusion, these findings indicate that dairy fat consumed in the form of cheese has a differential effect on blood lipid responses relative to some other dairy food structures. However, owing to considerable heterogeneity and limited studies, further confirmation from RCTs is warranted. TRIAL REGISTRATION NUMBER: This systematic review protocol was registered at https://www.crd.york.ac.uk/PROSPERO/ as CRD42022299748.

Serum Metabolomic Markers of Dairy Consumption: Results from the Atherosclerosis Risk in Communities Study and the Bogalusa Heart Study.

BACKGROUND: Dairy consumption is related to chronic disease risk; however, the measurement of dairy consumption has largely relied upon self-report. Untargeted metabolomics allows for the identification of objective markers of dietary intake. OBJECTIVES: We aimed to identify associations between dietary dairy intake (total dairy, low-fat dairy, and high-fat dairy) and serum metabolites in 2 independent study populations of United States adults. METHODS: Dietary intake was assessed with food frequency questionnaires. Multivariable linear regression models were used to estimate cross-sectional associations between dietary intake of dairy and 360 serum metabolites analyzed in 2 subgroups of the Atherosclerosis Risk in Communities study (ARIC; n = 3776). Results from the 2 subgroups were meta-analyzed using fixed effects meta-analysis. Significant meta-analyzed associations in the ARIC study were then tested in the Bogalusa Heart Study (BHS; n = 785). RESULTS: In the ARIC study and BHS, the mean age was 54 and 48 years, 61% and 29% were Black, and the mean dairy intake was 1.7 and 1.3 servings/day, respectively. Twenty-nine significant associations between dietary intake of dairy and serum metabolites were identified in the ARIC study (total dairy, n = 14; low-fat dairy, n = 10; high-fat dairy, n = 5). Three associations were also significant in BHS: myristate (14:0) was associated with high-fat dairy, and pantothenate was associated with total dairy and low-fat dairy, but 23 of the 27 associations significant in the ARIC study and tested in BHS were not associated with dairy in BHS. CONCLUSIONS: We identified metabolomic associations with dietary intake of dairy, including 3 associations found in 2 independent cohort studies. These results suggest that myristate (14:0) and pantothenate (vitamin B5) are candidate biomarkers of dairy consumption.

Consumer-Led Investigation into Potential Issues That Arise When Testing Dairy Matrixes for Gluten With the NIMA Sensor.

BACKGROUND: Some consumers with celiac disease use personal, point-of-use gluten detection devices to test food. False-positive results may occur due to sampling, matrix effects, and sensor issues. OBJECTIVE: The purpose of the present study was to determine if the positive gluten results some users were obtaining when testing cream cheese and materials of similar consistency were false positives and, if so, what might be causing them to occur. METHODS: Cream cheese, soft cheese, and yogurt were tested for gluten using the Ridascreen Gliadin R7001 sandwich R5 ELISA and the Ridascreen Gliadin R7021 competitive R5 ELISA. Two test portions were taken, extracted, and tested from each homogenized material. Materials were also analyzed for gluten using a NIMA sensor, a personal, point-of-use gluten detection device. Multiple test portion weights were tested beginning at 0.13 to 0.17 g (the ideal weight of the test portion according to the NIMA sensor development team). RESULTS: Using the sandwich R5 ELISA and the competitive R5 ELISA, all materials tested below the lower LOD for gluten. Using a NIMA sensor, as the weight of the test portion tested increased, sensor results went from no gluten found, to gluten found, to no test result. CONCLUSION: The gluten found results using the NIMA sensor are likely false positives that appear to correspond with the weight and volume of the material tested, as well as the viscosity. There is also an apparent disconnect between the gluten found result reported by the sensor and an interpretation of the lateral flow device (LFD) strip result when assessed by eye which should also be taken into account. Ideally, NIMA sensor users should be advised on the weight amount of material to analyze and test portions should be weighed before being used with the NIMA sensor. However, this is not a practical solution when testing in many environments, including restaurants. HIGHLIGHTS: Slight variations in weight and volume of test materials can result in false positive results when testing dairy matrixes for gluten using the Nima sensor.

Plasma Fatty Acid Biomarkers of Dairy Consumption Are Associated with Sex-Dependent Effects on Metabolic Syndrome Components in Mexican Adolescents.

INTRODUCTION: During adolescence, dairy product intake has shown conflicting associations with metabolic syndrome (MetS) components, which are risk factors for cardiovascular disease (CVD). This study aims to investigate the association between plasma fatty acids (FAs) C15:0, C17:0, and t-C16:1n-7, as biomarkers of dairy intake, with MetS and its components in Mexican adolescents. METHODS: A sample of 311 participants from the Early Life Exposure in Mexico City to Environmental Toxicants (ELEMENT) cohort was included in this cross-sectional analysis. FA concentrations were measured in plasma as a percentage of total FA. We used quantile regression models stratified by sex to evaluate the association between FA quantiles and MetS components, adjusting for age, socioeconomic status (SES), sedentary behavior, BMI z-score, pubertal status, and energy intake. RESULTS: We found significant associations between dairy biomarkers and the median of MetS variables. In females, t-C16:1n-7 was associated with a decrease of 2.97 cm in WC (Q4 vs. Q1; 95% CI: -5.79, -0.16). In males, C15:0 was associated with an increase of 5.84 mm/Hg in SBP (Q4 vs. Q1; CI: 1.82, 9.85). For HDL-C, we observed opposite associations by sex. C15:0 in males was associated with decreased HDL-C (Q3 vs. Q1: ß = -4.23; 95% CI: -7.98, -0.48), while in females, C15:0 and t-C16:1n-7 were associated with increased HDL-C (Q3 vs. Q1: ß = 4.75; 95% CI: 0.68, 8.82 and Q4 vs. Q1: ß = 6.54; 95% CI: 2.01, 11.07), respectively. Additionally, in both sexes, different levels of C15:0, C17:0, and t-C16:1n-7 were associated with increased triglycerides (TG). CONCLUSION: Our results suggest that adolescent dairy intake may be associated in different directions with MetS components and that associations are sex-dependent.

Detection of Soybean-Derived Components in Dairy Products Using Proofreading Enzyme-Mediated Probe Cleavage Coupled with Ladder-Shape Melting Temperature Isothermal Amplification (Proofman-LMTIA).

Food adulteration is a serious problem all over the world. Establishing an accurate, sensitive and fast detection method is an important part of identifying food adulteration. Herein, a sequence-specific ladder-shape melting temperature isothermal amplification (LMTIA) assay was reported to detect soybean-derived components using proofreading enzyme-mediated probe cleavage (named Proofman), which could realize real-time and visual detection without uncapping. The results showed that, under the optimal temperature of 57 °C, the established Proofman-LMTIA method for the detection of soybean-derived components in dairy products was sensitive to 1 pg/µL, with strong specificity, and could distinguish soybean genes from those of beef, mutton, sunflower, corn, walnut, etc. The established Proofman-LMTIA detection method was applied to the detection of actual samples of cow milk and goat milk. The results showed that the method was accurate, stable and reliable, and the detection results were not affected by a complex matrix without false positives or false negatives. It was proved that the method could be used for the detection and identification of soybean-derived components in actual dairy products samples.

Detection of Vegetable Oil Adulteration in Pre-Grated Bovine Hard Cheeses via 1H NMR Spectroscopy.

Adulteration of food products is a widespread problem of great concern to society and dairy products are no exception to this. Due to new methods of adulteration being devised in order to circumvent existing detection methods, new detection methods must be developed to counter fraud. Bovine hard cheeses such as Asiago, Parmesan, and Romano are widely sold and consumed in pre-grated form for convenience. Due to being processed products, there is ample opportunity for the introduction of inexpensive adulterants and as such, there is concern regarding the authenticity of these products. An analytical method was developed using a simple organic extraction to verify the authenticity of bovine hard cheese products by examining the lipid profile of these cheeses via proton Nuclear Magnetic Resonance (NMR) spectroscopy. In this study, 52 samples of pre-grated hard cheese were analyzed as a market survey and a significant number of these samples were found to be adulterated with vegetable oils. This method is well suited to high throughput analysis of these products and relies on ratiometrics of the lipids in the samples themselves. Genuine cheeses were found to have a very consistent lipid profile from sample to sample, improving the power of this approach to detect vegetable oil adulteration. The method is purely ratiometric with no need for internal or external references, reducing sample preparation time and reducing the potential for the introduction of error.

Enhanced Automated Online Immunoaffinity Liquid Chromatography-Fluorescence Method for the Determination of Aflatoxin M1 in Dairy Products.

BACKGROUND: Aflatoxin M1 (AFM1) is found in the milk of cows exposed to feed spoiled by Aspergillus fungi species. These fungi may produce the secondary metabolite aflatoxin B1, which is converted in the cow liver by hydroxylation to AFM1 and is then expressed in milk. AFM1 is regulated in milk and other dairy products because it can cause serious health issues, such as liver and kidney cancers, in humans and is an immunosuppressant. OBJECTIVE: To optimize the chromatographic protocol and to extend the matrix scope to include a wider range of dairy products: whey powder, whey protein concentrate, whey protein isolate, liquid milk, skim milk powder, whole milk powder, adult nutritional products, and yogurt. METHODS: AFM1 is extracted using 1% acetic acid in acetonitrile incorporating ionic salts. The AFM1 in the resulting extract is concentrated using an automated RIDA®CREST IMMUNOPREP® online cartridge coupled to quantification by HPLC-fluorescence. RESULTS: The method was shown to be accurate, with acceptable recovery (81.2-97.1%) from spiked samples. Acceptable precision was confirmed, with a relative standard deviation (RSD) for repeatability of 6.6-11.2% and an RSD for intermediate precision of 7.5-16.7%. Method LOD and robustness experiments further demonstrated the suitability of this method for routine compliance testing. Analysis of an international proficiency trial sample generated results that were comparable with the value assigned from alternative independent methods. CONCLUSION: A method with improved chromatography for high-throughput, routine testing of AFM1 in an extended range of dairy products is described. The method was subjected to single-laboratory validation and was found to be accurate, precise, and fit for purpose. HIGHLIGHTS: Single-laboratory validation of an automated online immunoaffinity cleanup fluorescence HPLC method for AFM1 in whey proteins, milk powders, nutritional products, liquid milk, and yogurt. Allows for high-throughput analysis of AFM1 with enhanced chromatographic performance. Method applicable to the analysis of AFM1 in an extended range of milk and milk-based products.

Emerging biosensors to detect aflatoxin M1 in milk and dairy products.

Aflatoxin M1 (AFM1) is an important risk factor threatening the safety of milk and dairy products due to its carcinogenic and teratogenic effects on humans. To prevent AFM1 from causing damage to human health, developing reliable methods to monitor its levels in milk and dairy products is of great importance. Biosensors built with recognition and detection systems have attracted extensive attention for their simplicity, portability, sensitivity, and selectivity. The commonly developed biosensors for detecting AFM1 are antibody-based sensors (immunosensors) and aptamer-based sensors (aptasensors). This review focused on the advances of immunosensors, aptasensors, and other emerging receptors-based sensors for the detection of AFM1 in milk and dairy products in the past five years. These biosensors were reviewed with representative examples according to their signal transduction systems, mainly including colorimetry, fluorescence, electrochemistry, and others. The unique advantages and drawbacks of immunosensor and aptasensor, and the future opportunities and challenges were also discussed.