Recent aflatoxin survey data in milk and milk products: A review

Aflatoxin M₁ (AFM₁) occurrence in human and animal milk, infant formula, powdered milk, cheese and yoghurt represents a risk for health. The last four years (2010–2014) of data, as well as the most frequently and updated analytical methods applied for AFM₁ quantification, are evaluated. Aflatoxin B₁, considered the most potent toxic aflatoxin, is metabolised to form the monohydroxy derivative AFM₁. This metabolized, expressed in the milk, is relatively stable, and it is not eliminated by heat treatments or pasteurisation, and thus represents a serious health concern.     

First tests of standardized biocrystallization on milk and milk products

The biocrystallization method has been standardized for plant products. The standardized biocrystallization method is tested on milk and butter samples from controlled feeding trials. When computerized image analysis is applied, samples from different origins (feeding regimes) can be distinguished significantly.     

Near‐infrared spectroscopy and data analysis for predicting milk powder quality attributes

Near‐infrared (NIR) spectroscopy is a rapid analytical method for food products. In this study, NIR spectroscopy, data pretreatment techniques and multivariate data analysis were used to predict fine particle size fraction, dispersibility and bulk density of various milk powder samples, which are believed to have a significant impact on milk powder quality. Predictive models using partial least‐squares (PLS) regression were developed using NIR spectra and milk powder physical and functional properties, and it was concluded that the PLS models predicted milk powder quality with an accuracy of 88‐90 per cent.     

Dioxins and furans in cow milk and dairy products: A review of the scientific literature

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a group of persistent organic pollutants with well-known toxic effects and potential carcinogenicity. Human exposure to PCDD/Fs is mainly through food, including dairy products. The scientific information on the concentrations of PCDD/Fs in milk and dairy products is here reviewed. It also includes the intake of PCDD/Fs through the consumption of these products. PCDD/Fs concentrations in milk and dairy products are currently decreasing. A similar trend is also noted for their contributions to the total dietary intake of PCDD/Fs. No significant health risks due to exposure to PCDD/Fs through the consumption of dairy products are expected.     

Critical assessment of formulation,processing and storage conditions on the quality of alveolar baked products determined by different analytical techniques: A review

BackgroundSensorial, nutritional and microbiological deteriorations of alveolar bakeries are mostly hazardous for producers that are threatened by the loss of consumers’ confidence and market shares. These alterations induce loss of the freshness, which is the first feature of purchasing. Hence, monitoring the quality of baked products has been determined by using different analytical techniques (e.g., rheology, chromatography, sensory analyses, etc.). To date, these tools are used as reference ones, but, they come under criticism due to their destructive and sophisticated aspects. Therefore, many newest techniques have been investigated in order to provide reliable data in a short time and a cheap way without the need of samples preparation.Scope and approachThis review will discuss firstly the techno-functional properties of the lipid component in the formulation of alveolar products and attempts of its reduction and/or substitution. Then, the optimization of bakeries processing will be presented. The macroscopic and molecular techniques commonly used for monitoring quality, freshness and alteration of the alveolar products are finally reviewed.Key findings and conclusionsThe potentialities of vegetable oils combined with fibers to reduce the saturated fatty acids content in recipe are highlighted. This review provides also a comprehensive approach for the optimization of alveolar goods processing in order to maintain the nutritional quality of the final product. Regarding quality and freshness control, this review emphasizes the complementarity between traditional methods and innovative ones, including spectroscopic techniques in combination with chemometric tools for understanding the molecular and macroscopic structure of alveolar baked products.     

Residue analysis of melamine in milk products by micellar electrokinetic capillary chromatography with amperometric detection

A high-performance micellar electrokinetic capillary chromatography with amperometric detection (MECC–AD) method for the fast determination of melamine (MM), occasionally used to increase the apparent protein content of milk products, has been developed. Method development involved optimisation of the working electrode, the running buffer system and acidity, the concentration of sodium dodecyl sulphate (SDS), the separation voltage, the applied potential and the sample injection time. Under the optimum conditions, MM can be well separated from its co-existing interferences in real-world samples within 9 min at the separation voltage of 20 kV in a 8 mmol/L SDS/20 mmol/L H₃BO₃–Na₂B₄O₇ running buffer (pH 7.4). Satisfactory recovery (83.3–105.5%), repeatability of the peak current (3.2%) and migration time (3.8%), and the limit of detection (2.1 × 10⁻⁶ g/mL) for the method were achieved. This proposed procedure has been successfully used for the determination of MM in milk products.     

The use of carbon dioxide in the processing and packaging of milk and dairy products: A review

The upswing in consumer demand for fresh and high quality preservative‐free foods has led to the development of modified atmosphere packaging (MAP). Increasingly, MAP is being used with high carbon dioxide (CO₂) concentration as well as CO₂/N₂ gas mixes. Modified atmosphere packaging or ‘gas flushing’ as it is also known is an increasingly popular technique used to extend the shelf life (both quality and safety) of a number of dairy products. Carbon dioxide is an active constituent of MAP, naturally present in freshly drawn raw milk. Addition of CO₂ to raw milk or flushing the package headspace has proved to be a simple and cost‐effective method, depending upon the initial microbiological quality of the food product. Carbon dioxide addition through MAP or direct injection as an economically affordable shelf life extension strategy is used commercially worldwide for some dairy products. The development of food packaging machines with integrated gas flushing capabilities and the supply of ‘food grade’ gases allow dairy foods manufacturers to enhance the quality of their products. This review presents a broad spectrum of current research and the current trends with respect to CO₂ as a natural microbial hurdle with special focus on its precise mechanism and its role in quality improvement of dairy products.     

乳及乳制品中磷脂检测技术研究进展

乳及乳制品作为人们日常消费的商品, 其营养价值十分丰富, 其中以乳脂为代表的一大类营养成分起到重要作用。磷脂作为乳脂重要组成成分, 具有多种生理功能, 与人类健康、疾病密切相关, 在国内外广受关注。磷脂组学是通过定性及定量分析磷脂化合物从而开展相关研究的学科, 而磷脂分析技术是实现磷脂组学研究的关键步骤。基于此, 本文综述了磷脂的分类、结构、作用及检测方法4个方面, 对磷脂的分类和结构做了详细介绍, 对磷脂的功能作用进行了总结论述, 对磷脂的分析检测方法进行了查新及对比研究, 最后展望了乳及乳制品中磷脂类化合物的检测发展趋势, 并阐述了乳及乳制品中磷脂学研究的意义, 即建立乳及乳制品中以磷脂为标示物的指纹图谱便于真假鉴别, 以及缩小婴幼儿配方乳粉与母乳之间的差异以减少对母乳的依赖。     

Natural antioxidants in milk and dairy products

Milk antioxidants, both lipophilic (conjugated linoleic acid, α‐tocopherol, β‐carotene, vitamins A and D₃, coenzyme Q₁₀, phospholipids) and hydrophilic antioxidants (proteins, peptides, vitamins, minerals and trace elements) play a key role in maintaining pro‐oxidant and antioxidant homeostasis in the human body. Lipophilic antioxidants are characterised by high thermal stability and they are active in all dairy products. Lipophilic and hydrophilic antioxidants interact in the process of deactivating reactive oxygen species and the final products of lipid peroxidation. A negative correlation between milk consumption and the incidence of diet‐dependent diseases confirms that the consumption of milk and dairy products delivers health benefits.     

巴氏消毒乳储存过程中化学与微生物变化

通过研究不同储存温度的巴氏消毒乳感官品质、生化指标和微生物数量,来确定影响巴氏消毒乳品质的主要因素。结果表明,在5 d的储存期内,巴氏消毒乳在4℃和8℃储存条件下感官品质变化趋势几乎一样,在12℃储存条件下感官品质下降趋势较4℃和8℃储存条件下快。巴氏消毒乳中脂肪酶的活力、TBARS值和蛋白水解程度均随着储存时间的延长而逐渐升高,SDS-PAGE显示主要蛋白未见明显分解,金黄色葡萄球菌未检出,嗜冷菌的数量逐渐减少,菌落总数呈现对数生长趋势并在储存的第4天达到稳定期。巴氏消毒乳中残存的脂肪酶、蛋白酶和微生物是影响巴氏消毒乳品质的主要因素。     

Fingerprint of enological tannins by multiple techniques approach

In this study, six enological tannins (T1–T6) from different source were analysed by selected analytical techniques, including UV–Vis, FTIR, NMR, SEC, LC-MS/MS and electronic nose. Moreover, the samples were tested for their antioxidant activity. Spectra and chromatograms are considered as a fingerprint with a pattern that is distinctive for a given type of sample. In particular, tannins showed the maximum UV–Vis absorbance (λ_max) at 273–280 nm, the inflection point (λ_min) at 247–264 nm, and the ratio λ_max/λ_min was 1.03, 1.35, 1.67, 1.36, 2.15, 2.02 for tannin T1–T6, respectively. The FTIR analysis of tannins showed the presence of most important absorption bands at 1522, 1453, 1380, 1350, 1328, 1286, 1210, 1148 and 1044 cm⁻¹. Besides, SEC and NMR analysis allowed to sort the tannins according to their average DP as follows: T1 > T2 = T4 > T3 > T6 = T5. Based on this multiple techniques approach three condensed tannins (sample T3, T5 and T6) were clearly identified, together with two mixtures of hydrolysable tannins (sample T1 and T2), whereas one sample (T4) showed a peculiar pattern different from the commercial tannin commonly used in enology.     

Polycyclic aromatic hydrocarbons in milk and dairy products

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds with a structure consisting of carbon and hydrogen atoms that have more than two fused aromatic rings. Most PAHs have carcinogenic effects on animal or humans and induce various cancers. Polycyclic aromatic hydrocarbons are a consequence of environmental pollutants, imperfect burning or pyrolysis of organic substances during industrial processing. Additionally, foods can be contaminated during their processing and preparation through different heat treatments. This review highlights the formation, occurrence and health impacts of PAHs in milk and milk products, and analytical technique used for their determination in dairy products.     

奶制品中抗生素的检测

介绍奶制品中抗生素残留危害性并分析比较了两种抗生素检测方法。     

Survey of the microbiological quality of the raw cow milk in the Tadla area of Morocco

Cow milk samples were collected during three periods and from four milk collection centres located in four different geographical zones. Samples were analysed for their standard plate count, enterococci, total coliform and feacal coliform, lactic acid bacteria, spoilage bacteria and some of the pathogenic bacteria. The most contaminated cooperatives were those located essentially in the irrigated zones. The less contaminated ones belong to semipublic farms. It seems that transportation, milking and pre‐storage conditions constitute the main basic relevant factors for heavy bacterial contamination. This is the first survey of the microbiological characteristics of raw milk produced in the Tadla area of Morocco.     

Effect of heat treatment on milk protein functionality at emulsion interfaces. A review

Heat treatment affects the molecular structure of milk proteins at the interfaces of oil-in-water emulsions and in aqueous media. Experimental evidence of the impact of thermal processing on milk protein structure is presented and the contribution of whey proteins and caseins at film formation during emulsification is discussed. Recent advances in understanding the effect of heat treatment in milk protein functionality at emulsion interfaces are reviewed with particular emphasis on the emulsifying ability of whey proteins with or without the presence of the casein fraction. The major findings regarding the destabilizing mechanisms of oil-in-water emulsions brought about by heat-induced denaturation of milk proteins are presented. This paper aims to combine recent knowledge on how thermal processing of milk proteins affects their molecular configurations in bulk and particularly at interfaces, which in turn appear to be important with respect to the physico-chemical properties of milk protein-stabilized emulsions.     

浊点萃取-高效液相色谱法检测牛奶中的 喹诺酮类抗生素

目的建立浊点萃取-高效液相色谱(紫外检测器)技术检测牛奶中6种喹诺酮类药物的分析方法。方法牛奶样品采用冰乙酸和无水硫酸钠破乳,经Tween 20表面活性剂萃取后,加入浓氨水、正丁醇、无水硫酸钠,在50℃水浴锅中进行平衡分离,将分离出的水相去除,表面活性剂相进高效液相色谱仪检测分析。结果 6种喹诺酮类药物在0.05~2μg/m L范围内线性关系良好(r~2≥0.9991),检出限(S/N=3)为8.27~10.81μg/L。6种喹诺酮类药物在0.05、0.1、0.2 mg/L 3个水平回收率为71.3%~96.8%,相对标准偏差为1.24%~6.02%,结论该方法准确、灵敏,符合多残留检测和痕量分析的技术要求。     

高效液相色谱法测定牛奶中氯霉素残留量的研究

为了快速、简便、灵敏地测定牛奶中的氯霉素残留，建立了高效液相色谱分析法，牛奶样品先用含1％高氯酸的乙酸乙酯沉淀蛋白质和提取氯霉素，提取液浓缩干后用0.5mol/L高氯酸溶液溶解，以正己烷去除脂溶性杂质，在波长278nm处用高效液相色谱仪测定氯霉素，本方法最低检出浓度为1．1μg/kg，氯霉素浓度在20μg/kg－100μg/kg范围内，方法平均回收率为88．0％－97．7％，RSD为5．3％－6．4％，本方法适于牛奶中氯霉素残留的监测。     

Persistent organochlorine pesticide residues in milk and dairy products in India

Monitoring of milk and dairy product samples of various brands from different cities in Maharashtra, India, was carried out to determine if there is any contamination due to organochlorine pesticide residues. The measurements were made using a gas chromatograph-electron capture detector system. Trace levels of DDT and HCH were detected in the samples. Total HCH levels in milk and milk product samples were lower than total DDT levels, which could be attributed to earlier extensive antimalaria sanitary activities. Butter had higher levels of DDT than cheese and milk powder. All levels of organochlorine pesticide residues in milk and milk products were well below the maximum permissible limits given by the FAO/WHO. More importantly, as compared with an earlier report, present levels of the contaminants are substantially lower, which indicate the gradual phase out of these compounds.