Development of an LC-MS/MS method to quantify sex hormones in bovine milk and influence of pregnancy in their levels

Hormones work in harmony in the body, and this status must be maintained to avoid metabolic disequilibrium and the subsequent illness. Besides, it has been reported that exogenous steroids (presence in the environment and food products) influence the development of several important illnesses in humans. Endogenous steroid hormones in food of animal origin are unavoidable as they occur naturally in these products. The presence of hormones in food has been connected with several human health problems. Bovine milk contains considerable quantities of hormones and it is of particular concern. A liquid chromatography–tandem mass spectrometry (LC-MS/MS) method, based on hydroxylamine derivatisation, has been developed and validated for the quantification of six sex hormones in milk [pregnenolone (P₅), progesterone (P₄), estrone (E₁), testosterone (T), androstenedione (A) and dehydroepiandrosterone (DHEA)]. This method has been applied to real raw milk samples and the existence of differences between milk from pregnant and non-pregnant cows has been statistically confirmed. Basing on a revision of existing published data, it could be concluded that maximum daily intakes for hormones are not reached through milk ingestion. Although dairy products are an important source of hormones, other products of animal origin must be considered as well for intake calculations.     

Determination of naturally occurring progestogens in bovine milk as their oxime derivatives using high performance liquid chromatography–electrospray ionization–tandem mass spectrometry

BACKGROUND: Hormones and hormone‐like substances which are present in the environment have been repeatedly accused of being the cause of most endocrine disruption. However, the possible role of endogenous hormones in food of animal origin deserves to be discussed as well. The relation between steroid hormones and several human health problems has been previously reported, such as prostate and breast cancer, perturbation of human reproduction and endocrine disruption on humans and wildlife. This research is particularly concerned with cow's milk, which contains a considerable amount of sex hormones. RESULTS: A liquid chromatography–tandem mass spectrometry method has been developed for the simultaneous detection and quantification of four naturally occurring steroid hormones in commercial bovine milk (pregnenolone (P₅), progesterone (P₄), 17‐hydroxypregnenolone (17‐OHP₅), 17‐hydroxyprogesterone (P₄)). Oxime derivatives of steroids were analyzed in positive ionization and multiple reaction monitoring mode. Methodology has been validated according to Decision 2002/657/EC criteria. CONCLUSION: This method has been successfully used in real samples. It is fast and easy‐handling and provides a useful tool for the assessment of progestogens in bovine milk. Copyright © 2010 Society of Chemical Industry     

Analytical authentication of organic products: an overview of markers

Consumers' interest in organic foods is increasing and so is the need for robust analytical tools for their authentication. This review focuses on the most promising biomarkers/analytical approaches that are available for the authentication of organic produce. Food products have been subdivided into two groups: foods of plant origin (crops) and foods of animal origin (meat, milk and dairy products, eggs and fish). For each food category the most suitable biomarkers are presented and their potential for authentication is discussed. In the light of current knowledge, it is unlikely that the authentication of organic food products can be attained by the measurement of a single marker. Analytical approaches based on the measurement of multiple markers and/or complex chemical or physical profiles/fingerprints supported by multivariate statistical analysis seem considerably more promising in this respect. For the development of robust classification models, well‐designed experimental studies must be performed that rely on data sets that are both well balanced and of sufficient size to ensure that all relevant sources of variation for the target biomarkers are included in the reference database. Copyright © 2012 Society of Chemical Industry     

Chromatographic Methods for the Determination of Carbohydrates and Organic Acids in Foods of Animal Origin

Carbohydrates are ubiquitous and range from simple monosaccharides to large complex polysaccharides. Organic acids are compounds with acidic properties. Both occur naturally in many foods and in fermented products. Organic acids are usually derived from the hydrolysis of carbohydrates by microorganisms such as lactic acid bacteria. These bacteria convert carbohydrates into energy required for growth, since they are not equipped with the enzymes necessary for respiration and are unable to perform oxidative phosphorylation. Determination of carbohydrates and organic acids in foods of animal origin is important, since they contribute to flavor and texture. Their presence and proportions can affect the chemical and sensory characteristics of a food matrix and they can provide information on nutritional properties of food and the means to optimize selected technological processes. Furthermore, the levels of carbohydrate and organic acid are important to monitor bacterial growth and activity. Actually, these compounds can be quantified by several methods including high‐performance liquid chromatography (HPLC) and gas chromatography (GC). High‐performance liquid chromatography has been widely used to analyze carbohydrates and nonvolatile organic acids, while gas chromatography has been used to determine the volatile organic acids in complex matrices. This contribution provides an overview of chromatographic methods (HPLC and GC) used to analyze carbohydrates and organic acids in foods of animal origin.     

Practical Food Safety Interventions for Dairy Production

Consumers are increasingly concerned about the safety of their food and uncertain about food production practices. Potential threats to human health related to dairy products and dairy farming include errors in pasteurization, consumption of raw milk products, contamination of milk products by emerging heat-resistant pathogens, emergence of antimicrobial resistance in zoonotic pathogens, chemical adulteration of milk, transmission of zoonotic pathogens to humans through animal contact, and foodborne disease related to cull dairy cows. Most dairy farmers feel responsible for the safety of milk and beef that originate on their farms, but linkage between farm production practices and the quality of processed products have been weak. The safety of dairy products can be enhanced by adoption of a number of management practices. Sources of microbial contamination of milk must be minimized by adoption of hygienic standards that can be easily evaluated. Uniform adoption of milking practices that reduce microbial contamination of milk should be emphasized. The diagnosis of salmonellosis or listeriosis on a dairy farm should be regarded as an indication that other potentially infected animals may be present in the herd. Coliform counts on bulk tank milk should be routinely performed as an indicator of fecal contamination. A reduction in the national regulatory limit for somatic cells in bulk tank milk should be considered based on potential enhancements in milk safety. Dairy farmers must take responsibility for the market cattle leaving their farms. The inappropriate or prophylactic use of antimicrobial agents must be minimized to ensure that antimicrobial resistance does not develop in animal pathogens. Consumers can have confidence in food safety programs on dairy farms that promote awareness and accountability for the products that are produced.     

Cholesterol Oxides in Foods of Animal Origin

The earliest discovery of an oxidation product of cholesterol from a natural source was reported in 1940. Additional discoveries of cholesterol oxidation products (COPS) in edible food products accelerated in the 1980s as gas chromatography and high performance liquid chromatography detection methods were improved. COPS have been found in several foods including liquid eggs and dried egg products, milk and milk products, meat and meat products, marine food products, and other processed foods. Compelling evidence demonstrates that several cholesterol oxides are cytotoxic, atherogenic, mutagenic, and carcinogenic. Therefore, the presence of COPS in foods raises questions about the safety of consumption of some products.     

Endocrine factors in genetic improvement of milk production.

The endocrine role in lactation is undisputed, but attempts to correlate milk production with various endocrine products have had limited success. Recent work has suggested that placental hormones, in particular placental lactogen, may be an important regulator of lactation capacity. In addition to concentrations of hormones in blood, it is important to consider receptors in target tissue for the hormones. The concentration of receptors in a tissue may vary with genotype of the individual or under the influence of hormonal state. Other aspects of the target tissue's system for response also must be considered.     

食品及生物样品中L-羟脯氨酸检测技术研究进展

L-羟脯氨酸(L-hydroxyproline,Hyp)是动物水解蛋白的特征物质,而动物水解蛋白是可能被违法添加于食品中尤其是乳与乳制品中的非食用物质之一,Hyp可作为判定食品中是否掺入动物水解蛋白的重要指标.建立快速、高效地Hyp检测方法,提高其检测灵敏度和回收率,是食品质量安全监控的重要任务.本文就食品及生物样品中L-羟脯氨酸的提取净化、衍生化及测定方法研究进展进行了综述.     

Mercury, chromium, lead and organochlorine pesticide residues in some food products of animal origin: A review

The authors present the results of several years' work in the field of food pollution. The research, which has been carried out on food products of animal origin marketed in the north of Italy, has established that the degree of contamination by heavy metals (mercury, chromium and lead) and organochlorine pesticides is generally lower than the tolerances suggested by the World Health Organisation.     

Educational interventions to address misconceptions about antibiotic residues in milk can alter consumer perceptions and may affect purchasing habits

The industrialization of the agri-food industry and resultant decrease in the number of people employed on farms has contributed to a knowledge gap among consumers about food production processes. A commonly reported concern of dairy consumers is the use of antibiotics in dairy animals, even though these drugs are an important tool for promoting animal health and welfare and food safety. The extent to which consumers are aware of antibiotic residue avoidance practices in dairy production is unknown, and it is unclear whether acquisition of such knowledge could affect purchasing behavior and perceptions of dairy farming. The objectives of this study were to assess consumers' perceptions about the quality and production of dairy products in the United States and determine whether educational materials on processes that limit the occurrence of antibiotic residues in milk can change consumers' perceptions of dairy products and purchasing behaviors. We surveyed 804 consumers and assigned them to 1 of 3 interventions: (1) a control arm (reading the content of the Dairy page of the USDA's myplate.gov website); (2) an educational brochure on the processes that prevent antibiotic residues in milk; and (3) a video on the same processes. We found that a majority (86.1%) of participants believe that the quality of dairy products in the United States is high, although many had concerns about the treatment of dairy animals and chemicals (pesticides, antibiotics, hormones) in dairy products. Compared with the control intervention, the brochure was associated with a significant decrease in the level of concern consumers had about chemicals in their milk [−0.20 points on a Likert scale, 95% confidence interval (CI), −0.32 to −0.08] and a significantly increased comfort in purchasing conventional dairy products (odds ratio 2.43, 95% CI, 1.62 to 3.66). The video was associated with even stronger effects: a 0.29-unit decrease in the level of concern about chemicals in milk (95% CI, −0.42 to −0.016) and 2.94 times greater odds of purchasing conventional dairy products (95%, CI 1.92 to 4.49). Although consumer food decision making is complex and driven by multiple factors, it appears that education about the processes that promote food safety can reassure consumers about their concerns and potentially affect purchasing habits.     

肉制品中动物源性成分DNA检测方法的研究进展

肉制品主要成分标识的真实性是全球重要的食品安全问题之一,特别是肉制品中动物源性成分的掺假和标识问题已引发全球关注。如何对肉制品中动物源性成分进行鉴定和标识已成为产品真实性鉴定的热点。基于DNA分子稳定性强的优点,DNA检测技术被广泛用于食品安全检测和监测诸多领域,体现出了灵敏度高、特异性强等优势。本文重点从动物源性检测的靶序列DNA选择和DNA分析技术研究2个方面,阐述了肉制品中动物源性成分定性、定量检测技术的研究和应用,并讨论动物源性成分定量分析的可能性,为我国实施动物源性成分量化监管提供思路。     

Comparison of the pharmacokinetics of plant-based treatments in milk and plasma of USDA organic dairy cattle with and without mastitis

Organic dairy products are the second largest sector of the organic food market. Organic dairy products come from United States Department of Agriculture (USDA) certified organic dairy cattle that meet USDA organic standards. Organic dairy cattle in the US cannot be treated with antibiotics for mastitis, one of the costliest diseases of dairy cattle, and thus effective alternatives are needed. When any compound (medication or other non-food product) is used in a food producing animal, a withhold time for that compound that meets US Food and Drug Administration (FDA) standards for food safety must be applied to the animal and its products (like milk). However, there are no US FDA products approved for mastitis that maintain USDA certified organic dairy cattle’s organic status. Thus, we studied the pharmacokinetics of 3 compounds (garlic, thymol and carvacrol) used on organic both healthy and mastitic organic dairy cattle. We also used this information to estimate a milk withhold time using methods consistent with US FDA requirements. For thymol intra-mammary and carvacrol intra-mammary or topical administration, all compounds were partially absorbed into the body from the milk or skin. Thymol and carvacrol are measurable in plasma (at 0.0183 and 0.0202 µg/mL, respectively) after intramammary administration with similar elimination half lives of 1.7 h. Milk concentrations of thymol and carvacrol are much higher at 2.958 and 4.487 µg/mL in healthy cattle, respectively. Concentrations are not significantly different in cows with mastitis as compared to those in healthy cows. Despite these compounds being natural products, they should have a withhold time for milk of at least 24 h after administration. For garlic, levels remained below the limit of detection in milk and plasma and thus no withdrawal time appears to be needed for milk.     

Natural occurrence of progesterone in commercial milk products (author's transl)]

By means of radioimmunoassay the concentrations of progesterone in commercial milk products were determined. The values range from 1.4 ng/ml (skin milk) to 300 ng/g (butter). The results show a close correlation between progesterone and fat contents in milk products. It is discussed that - due to recent progress in analytical methods - hormones in their natural occurrence in food are now measurable in micro-quantities which were not yet considered to be of biological importance; these findings should provoke a revision of terms like "free of hormones" in the sense of "zero tolerances".     

A review of microbes and chemical contaminants in dairy products in sub-Saharan Africa

Animal milk types in sub-Saharan Africa (SSA) are processed into varieties of products using different traditional methods and are widely consumed by households to support nutritional intake and diet. Dairy products contain several microorganisms, their metabolites, and other chemical compounds, some with health benefits and many others considered as potential health hazards. Consumption of contaminated milk products could have serious health implications for consumers. To access the safety of milk products across SSA, studies in the region investigating the occurrences of pathogens as well as chemical compounds such as heat stable toxins and veterinary drug residues in animal milk and its products were reviewed. This is done with a holistic view in light of the emerging exposome paradigm for improving food safety and consumer health in the region. Herein, we showed that several published studies in SSA applied conventional and/or less sensitive methods in detecting microbial species and chemical contaminants. This has serious implications in food safety because the correct identity of a microbial species and accurate screening for chemical contaminants is crucial for predicting the potential human health effects that undermine the benefits from consumption of these foods. Furthermore, we highlighted gaps in determining the extent of viral and parasitic contamination of milk products across SSA as well as investigating multiple classes of chemical contaminants. Consequently, robust studies should be conducted in this regard. Also, efforts such as development cooperation projects should be initiated by all stakeholders including scientists, regulatory agencies, and policy makers to improve the dairy product chain in SSA in view of safeguarding consumer health.     

Invited review: Human,cow, and donkey milk comparison: Focus on metabolic effects

Milk is an important food of the daily diet. Many countries include it in their dietary recommendations due to its content in several important nutrients that exert beneficial effects on human health. Human milk is a newborn's first food and plays an important role in the growth, development, and future health of every individual. Cow milk is the type of milk most consumed in the world. However, its relatively high content of saturated fats raises concerns about potential adverse effects on human health, although epidemiological studies have disproved this association. Indeed, dairy consumption appear to be linked to a lower risk of mortality and major cardiovascular disease events. In the last few years many researchers have begun to focus their attention on both the production and quality of cow milk as well as the analysis of milk from other animal species to evaluate their effect on human health. The need to investigate the composition and metabolic effects of milk from other animal species arises from the adverse reactions of individuals in several groups to certain components of cow milk. It has emerged that donkey milk compared with that of other animal species, is the nearest to human milk and an excellent substitute for it. Milk from various animal species shows substantial differences in nutritional composition and distinct metabolic effects. In this review, we discussed the main compositional features and metabolic effects of 3 types of milk: human, cow, and donkey milk.     

Hormones in bovine milk and milk products: A survey

A survey of the published data on the occurrence of hormones in milk and milk products is presented. Bovine milk and colostrum contain a large number of hormones from either steroidic or peptidic origin. The main categories to which these molecules belong are gonadal (estrogens, progesterone, androgens), adrenal (glucocorticoids), pituitary (prolactin, growth hormone) and hypothalamic hormones (GRH, LH-RH, TRH). Other molecules, such as proteins related to the parathyroid hormone, insulin, somatostatin, calcitonin, bombesin, erythropoeitin and melatonin, are also of interest. The exact role of hormones in the development of the newborn is still not known, but it is believed that they may contribute to the growth of the newborn and to the development and maturation of its gastrointestinal and immune systems.     

Demonstration of the presence of aminoreductone formed during the Maillard reaction in milk

The Maillard reaction is a common chemical reaction that occurs in food and it generates multiple reaction products. Aminoreductone (AR) is one of the early-stage Maillard reaction products. At present the formation of AR has only been demonstrated in a model system consisting of a monosaccharide or disaccharide and an amino group-containing compound. There is no direct evidence to show the presence of AR in food. In this study, we demonstrated the formation and presence of AR in milk using a combination of 2,4-dinitrophenylhydrazine (DNP) and Cu²⁺. A DNP derivative of AR oxidised by Cu²⁺ was isolated and its detailed structure was identified by NMR analysis. We thus directly demonstrated the formation and presence of AR in milk.     

Investigation of palladium and platinum levels in food by sector field inductively coupled plasma mass spectrometry.

Over the last two decades, there has been increased concern regarding the impact of some noble metals, such as Pd and Pt, on human health. These elements pollute the environment due to their widespread use as catalytic converters and in medical applications. The risk they pose to human health and the environment is still controversial; however, literature data point to diet as an important source of uptake by the human body. Within this context, the total Pd and Pt content of several Italian food commodities has been investigated. A total of 90 samples, including flour products, vegetables and foodstuffs of animal origin (meat, milk and eggs), were collected and freeze-dried. Samples were analyzed by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) after chopping or crushing followed by freeze-drying and microwave (MW)-assisted acid digestion in a Class-100 clean-room. A mathematical approach was adopted to correct the mass signals for still unresolved interference (mDeltam = 300, 10 000). The lowest and highest concentrations of Pt, i.e. 17 and 93 ng kg(-1) (dry weight, dw), were found in vegetables and flour products, respectively. The lowest Pd level (2830 ng kg(-1) dw) was found in eggs and the highest (47 800 ng kg(-1) dw) in vegetables.     

Functionality of enterococci in dairy products

Enterococci have important implications in the dairy industry. They occur as nonstarter lactic acid bacteria (NSLAB) in a variety of cheeses, especially artisan cheeses produced in southern Europe from raw or pasteurised milk, and in natural milk or whey starter cultures. They play an acknowledged role in the development of sensory characteristics during ripening of many cheeses and have been also used as components of cheese starter cultures. The positive influence of enterococci on cheese seems due to specific biochemical traits such as lipolytic activity, citrate utilisation, and production of aromatic volatile compounds. Some enterococci of dairy origin have also been reported to produce bacteriocins (enterocins) inhibitory against food spoilage or pathogenic bacteria, such as Listeria monocytogenes, Staphylococcus aureus, Vibrio cholerae, Clostridium spp., and Bacillus spp. The technological application of enterocins, shown to be produced during cheese manufacture, led to propose enterococci as adjunct starter or protective cultures in cheeses. There is evidence that enterococci, either added as adjunct starters or present as nonstarter NSLAB, could find potential application in the processing of some fermented dairy products. Literature suggest that the complex biochemical and ecological phenomena explaining the technological functionality of the enterococci in dairy products, are still to be fully understood. Clearly, the clinical research on enterococci underlines also that the safety of dairy products containing enterococci is an issue that the industry must carefully address before proceeding to their application.     

Advances in dietary enrichment with n-3 fatty acids

Evidence for the effectiveness of the enrichment of food products with n-3 fatty acids by inclusion of either plant- or fish-derived materials in the diets of chickens, turkeys, ostriches, cows, pigs, and goats has been reviewed. Both linseed oil/meal and fish products can increase the levels of total n-3 fatty acids in animal products, including milk, eggs, meat, and deli products. The extent of this increase in n-3 fatty acid contents seems to be dependent on the nature of diet supplementation. Encapsulation of linseed oil may result in higher milk cow ALA contents, as compared to unprotected linseed oil. Available literature indicates that the levels of EPA and DHA in food products may be increased more, if the animals' diet was supplemented with fish products rather than linseed products. However, organoleptic properties of food products may be compromised. This pitfall may be reduced by the addition of antioxidants and/or application of micro-encapsulation. Generation of transgenic animals and plants has shown very promising results. Thus far, transgenic pigs and mice have been successfully generated. These animals have a low ratio of n-6:n-3 fatty acids in their tissues and milk. The advantages and disadvantages of the above-mentioned methods have been discussed. The evidence for health-promoting effects of such enriched food products has been included.