Trace metals in raw cows’ milk and assessment of transfer to Comté cheese

The concentration and prevalence of potentially toxic elements (PTEs) in cheese: a global systematic review and meta-analysis

The present study aimed to systematically review the concentration of different PTEs, including Arsenic (As), Mercury (Hg), Lead (Pb), and Cadmium (Cd) in cheese among some databases between 2000 and 2021 (from 57 included studies). Estimated concentrations of 160.78 (95% CI = 119.24-202.28), 15.68 (95% CI = 11.88-19.48), 16.94 (95% CI = 13.29-20.59), and 2.47 (95% CI = 1.70-3.23) µg/kg were calculated for As, Pb, Cd, and Hg, respectively. Most of the studies for PTEs are related to Pb, about 40% of the studies, compared to As, which has fewer studies. The results showed that As and Hg concentrations were lower than the Codex Alimentarius Commission standard limits. Nevertheless, Cd and Pb concentrations were higher than the standard limit values. Results showed that cheese making, the ripening period, fat content, and texture are influential factors in a high level of Pb and Cd in cheese samples.

Correlations of milk and serum element concentrations with production and management traits in dairy cows

The present study investigated the potential consequences, positive or negative, that selection for favorable production-related traits may have on concentrations of vitamin B₁₂ and key chemical elements in dairy cow milk and serum and the possible impact on milk healthiness, and associated benefits, for the dairy product consumer. Milk and serum samples (950 and 755, respectively) were collected from Holstein-Friesian dairy cows (n = 479) on 19 occasions over a 59-mo period, generating 34,258 individual records, and analyzed for concentrations of key trace and quantity elements, heavy metals, and milk vitamin B₁₂. These data were then matched to economically important production data (milk, fat, and protein yield) and management data (dry matter intake, liveweight, and body condition score). Multivariate animal models, including full pedigree information, were used to analyze data and investigate relationships between traits of interest. Results highlighted negative genetic correlations between many quantity and trace elements in both milk and serum with production and management traits. Milk yield was strongly negatively correlated with the milk quantity elements Mg and Ca (genetic correlation between traits, r_a = -0.58 and -0.63, respectively) as well as the trace elements Mn, Fe, Ni, Cu, Zn, and Mo (r_a = -0.32, -0.58, -0.52, -0.40, -0.34, and -0.96, respectively); and in serum, Mg, Ca, Co, Fe, and Zn (r_a = -0.50, -0.36, -0.68, -0.54, and -0.90, respectively). Strong genetic correlations were noted between dry matter intake with V (r_a = 0.97), Fe (r_a = -0.69), Ni (r_a = -0.81), and Zn (r_a = -0.75), and in serum, strong negative genetic correlations were observed between dry matter intake with Ca and Se (r_a = -0.95 and -0.88, respectively). Body condition score was negatively correlated with serum P, Cu, Se, and Pb (r_a = -0.45, -0.35, -0.51, and -0.64, respectively) and positively correlated with Mn, Fe, and Zn (r_a = 0.40, 0.71, and 0.55, respectively). Our results suggest that breeding strategies aimed at improving economically important production-related traits would most likely result in a negative impact on levels of beneficial nutrients within milk for human consumption (such as Mg, Ca, Fe, Zn, and Se).

Heavy Metal Levels in Milk and Serum of Dairy Cows from Different Farms Located near an Industrial Area

Simple Summary

The increase in waste in the environment due to anthropogenic activities has a strong negative effect on the health of the Earth. Heavy metals are the most important cause of environmental pollution, and they enter into the food chain with a severe negative impact on human and animal health. The presence of heavy metals in milk probably indicates the chronic exposure of animals to these elements, suggesting the usefulness of this biological matrix as an indicator of heavy metal contamination. Therefore, the evaluation of heavy metal concentrations in milk can be a useful tool to monitor the exposure to environmental pollutions and to safeguard the security of both human and animal health status and welfare.

Abstract

Background: Heavy metals are toxic, non-biodegradable substances able to enter the food chain of cows and then transfer to their milk. This study investigated the relationship between the heavy metal concentrations in serum and milk and the environmental pollutants exposure at two different farms in Ragusa, Italy. Methods: To evaluate the concentrations of aluminum (Al), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb), milk and serum samples were collected from 40 Friesian dairy cows from farm 1 at about 3.7 km from an industrial area (group 1) and 40 Friesian dairy cows from farm 2 at about 400 mt from a greenhouse and 6.0 km from a chemical fertilizer factory (group 2). Results: The concentrations of heavy metals measured in serum and milk showed no statistically significant differences between group 1 and group 2. No significant correlation between heavy metals in serum and milk in group 1 was observed. A positive correlation between Zn concentrations measured in milk and serum samples was observed in group 2 (r = 0.35, p = 0.03). Conclusions: The determination of heavy metals in serum and milk can be an important tool to detect the exposure to environmental pollutants and in monitoring the hygienic state of the environment in which milk is produced.

Concentrations of Essential Trace and Toxic Elements Associated with Production and Manufacturing Processes in Galician Cheese

The objective of this study was to determine the trace element composition and the toxic metal residues in Galician cow’s milk cheese produced in different systems (artisan, industrial, and organic). Fourteen elements (As, Cd, Co, Cr, Cu, Fe, Hg, I, Mn, Mo, Ni, Pb, Se, and Zn) were determined in 58 representative samples of Galician cheeses by inductively coupled plasma mass spectrometry. The toxic elements were present at low concentrations, similar to those reported for other unpolluted geographical areas. The essential elements were also within the normal range in cheeses. There were no statistically significant differences between smoked and unsmoked cheeses for any of the elements. Chemometric analyses (principal component analysis and cluster analysis) revealed that the industrial cheeses produced in Galicia using the milk from intensive dairy farms were different, in terms of elemental content, from artisan and organic cheeses, in which the elemental contents were similar.

S. M. Montenegro MC, Rodríguez-Díaz JM. Contaminants in the cow's milk we consume? Pasteurization and other technologies in the elimination of contaminants

Cow's milk is currently the most consumed product worldwide. However, due to various direct and indirect contamination sources, different chemical and microbiological contaminants have been found in cow's milk. This review details the main contaminants found in cow's milk, referring to the sources of contamination and their impact on human health. A comparative approach highlights the poor efficacy and effects of the pasteurization process with other methods used in the treatment of cow's milk. Despite pasteurization and related techniques being the most widely applied to date, they have not demonstrated efficacy in eliminating contaminants. New technologies have appeared as alternative treatments to pasteurization. However, in addition to causing physicochemical changes in the raw material, their efficacy is not total in eliminating chemical contaminants, suggesting the need for new research to find a solution that contributes to improving food safety.

Heavy Metal Levels in Milk and Cheese Produced in the Kvemo Kartli Region, Georgia

Milk and dairy products are among the most important food sectors in Georgia, and milk is considered one of the most essential foods in the human diet according to Georgian food culture. Kvemo Kartli is one of the major regions in Georgia for milk production. This region suffers from heavy metal contamination in soil and water because of the mining industry. This study was conducted to determine the concentrations of cadmium, lead, iron, zinc, copper, chromium, manganese, cobalt, nickel, selenium and molybdenum in milk and cheese and to evaluate whether the concentrations of these elements correspond to the permissible levels of toxic elements in milk and cheese for Georgia and the EU. In total, 195 milk samples and 25 cheese samples (16 from Imeruli cheese and nine from Sulguni cheese) were collected from nine different villages in the Kvemo Kartli region in Georgia: Chapala, Vanati, Bolnisi, Mtskneti, Sabereti, Ratevani, Khidiskuri, Kazreti, Kvemo Bolnisi. The determination of heavy metal in all samples was carried out by inductively coupled plasma-mass spectrometry. The research results show that the concentration of these elements in most milk samples is fairly constant for all villages and is less than the permissible levels, except for seven samples from the following villages: Kvemo Bolnisi, Bolnisi, Mitskineti and Ratawani, where the concentration of lead in the milk samples was higher than the permissible limits mentioned in the literature, ranging from 0.027 to 1003 mg L⁻¹. As for copper, its concentration in milk in Sabereti and Vanati villages was above the permissible limits according to the EU limit, ranging from 0.42 to 1.28 mg L⁻¹. For cheese samples, the concentration of cadmium, lead, copper, Co and Ni in the two types of cheese was less than the permissible limit according to the laws of Georgia. Finally, the heavy metal concentrations in Imeruli and Sulguni cheese for manganese (Mn), chromium (Cr), selenium (Se), molybdenum (Mo) zinc (Zn) and iron (Fe) were above the permissible limit. Thus, the study results showed that the consumption of milk does not pose a direct and serious threat to the health of consumers. As for the two types of cheese, future studies and continuous monitoring are necessary to assess the cheese content of trace elements and the risk of its consumption to the consumer.

Dietary risk of milk contaminated with lead and cadmium in areas near mining-metallurgical industries in the Central Andes of Peru

The mining-metallurgical industry in the central Andes of Peru is a source of lead (Pb) and cadmium (Cd) contamination in milk, and there are no studies on the impact of their ingestion. Using flame atomic absorption spectrometry, we quantified the concentration of these metals in raw milk produced in agroecological zones near these industries, and estimated the exposure and dietary risk in people aged 2-85 yr with minimum, average and maximum daily milk intake. In 2018, 40 raw milk samples were collected from 20 cows at two times of the year. The mean Pb and Cd concentrations were 577 ± 18.2 and 18.35 ± 5.4 μg/kg, all samples exceeded the maximum limits (ML). Children aged 2-5 and 6-15 yr, with average milk consumption, had Pb weekly intakes (WI) of 2019 and 2423 μg, exceeding the risk value; values for Cd 64 and 77 μg were below the risk values. In those older than 20 years the WI for both metals are below the risk values. The Dietary Risk Coefficient (DRC) to Pb in children younger than 8 years was >3 due to higher milk consumption in relation to body weight; for children aged 9-19 years it was 1.7 and 2.9, being <1 for those older than 20 yr. Cd RDCs were <1 at all ages, with the exception of 2-year-olds in the high milk consumption scenario (RDC > 1). There was notable evidence of Pb and Cd exposure risk from consumption of milk produced near mining-metallurgical activities, predominantly for children under 19-year-olds. In Peru there are no regulations for Pb and Cd in fresh milk and milk products, we recommended that ML for heavy metals in food be established.

Evaluating the Authenticity of the Raw-Milk Cheese Fontina (PDO) with Respect to Similar Cheeses

The implementation of quality assurance schemes for the assessment of PDO food authenticity is an issue involving manufacturers, traders, retailers and consumers. In this respect, reliable analytical methods are needed to integrate paper-trailing information. The feasibility of distinguishing the Italian Fontina PDO cheese from the generic Fontal cheese was preliminarily evaluated on a set of commercial samples by measuring selected parameters (pH, alkaline phosphatase activity, content of copper, volatiles, extent of proteolysis) related to the different manufacturing processes. The relative profile of free amino acids proved to be a promising tool. A new set of 41 samples of Fontina PDO cheese was collected at representative dairies within the recognized production area and analyzed for free amino acids. A chemometric model of Fontina PDO cheese was built based on the mean content and standard deviation of 15 free amino acids. On this basis, all of the PDO samples were correctly identified, whereas all of the Fontal cheeses were recognized as different cheeses.

Heavy metals levels in raw cow milk and health risk assessment across the globe: A systematic review

This systematic review presents the potential toxicity of heavy metals such as lead (Pb), mercury (Hg), cadmium (Cd), iron (Fe), nickel (Ni), aluminum (Al), and copper (Cu) in raw cow milk, focusing on their contamination sources and on the assessment of the related human health risk. Multiple keywords such as "raw cow milk, heavy metals, and human health" were used to search in related databases. A total of 60 original articles published since 2010 reporting the levels of these metals in raw cow's milk across the world were reviewed. Data showed that the highest levels of Ni (833 mg/L), Pb (60 mg/L), Cu (36 mg/L) were noticed in raw cow milk collected in area consists of granites and granite gneisses in India, while the highest level of Cd (12 mg/L) was reported in barite mining area in India. Fe values in raw cow milk samples were above the WHO maximum limit (0.37 mg/L) with highest values (37.02 mg/L) recorded in India. The highest Al level was (22.50 mg/L) reported for raw cow's milk collected close to food producing plants region in Turkey. The Target Hazard Quotients (THQ) values of Hg were below 1 suggesting that milk consumers are not at a non-carcinogenic risk except in Faisalabad province (Pakistan) where THQ values = 7.7. For the other heavy metals, the THQ values were >1 for Pb (10 regions out of 70), for Cd (6 regions out of 59), for Ni (3 out of 29), and for Cu (3 out of 54). Exposure to heavy metals is positively associated with diseases developments. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metals effects in future studies.

Can Moderate Levels of Organic Selenium in Dairy Cow Feed Naturally Enrich Dairy Products?

Simple Summary

Milk and dairy products, such as cheese and yogurt, can be useful sources of selenium-enriched products to increase human Se intake. We studied the effect of dairy cow feed supplementation with inorganic plus organic Se on milk yield, and on the Se enrichment of milk and dairy products to obtain naturally enriched products. Two groups of lactating cows were assigned to two feeding treatments, both with 0.240 mg Se/kg of ration dry matter: One was supplemented with inorganic Se, the other with a 60/40 ratio of inorganic Se/organic Se. The results showed that the inclusion of inorganic plus organic Se did not affect the yield or basic chemical composition of milk; however, the Se content of milk was higher with inorganic plus organic Se supplementation. Cheese from cows fed inorganic plus organic Se had a higher Se content, although this effect was not observed for yogurt. At a moderate level in the diet, sodium selenite plus Se yeast may be more effective than only inorganic Se, increasing the Se concentration in milk and cheese.

Abstract

This work studied the effect of dairy cow ration supplementation with inorganic plus organic Se on metabolic status, milk yield, and the quality of milk and dairy products, especially its Se content. Twenty multiparous Holstein Friesian lactating cows were assigned to two feeding treatments. The cows were fed with 22.5 kg dry matter (DM) of total mixed ration (11.75 kg DM of forage plus 10.75 kg DM of concentrate) by head. There were two different concentrates with the same Se content (0.240 mg/kg of ration DM) but with different Se sources: The control (CON) was supplemented with inorganic Se (sodium selenite); and the other (IOSe) was supplemented with sodium selenite plus organic Se (Sel-Plex^®), at 0.144 and 0.096 mg Se/kg of ration DM, respectively. The results indicated that, in general, the IOSe treatment did not modify the metabolic profile, and even decreased the total oxidant status (p < 0.05) and did not lead to a deterioration of quality and yield of milk. However, milk and cheese from IOSe had higher Se content (an increase of 29.7% and 38.2%, respectively) than CON (p < 0.01), but this effect was not observed in yogurt. In general, physical or sensorial parameters of cheeses did not show differences between treatments. Moderate inorganic plus organic Se supplementation may be more effective than inorganic Se, increasing the Se content in milk and cheese, without causing a deterioration in quality or productive parameters.

Heavy metal and pesticide levels in dairy products: Evaluation of human health risk

Cattle milk's health benefits can be compromised by the presence of contaminants. The levels of cadmium, copper, lead and zinc, and residues of dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), dichlorodiphenyltrichloroethane (DDT) were determined in soil, milk and cheese samples collected from cow farms from 3 Romanian areas with industrial and agriculture tradition. A new methodology was applied for the determination of the corrected estimated daily intake (cEDI) corresponding to the aggregate dietary exposure. For the risk assessment, we calculated the source hazard quotient (HQs) for each contaminant and the adversity specific hazard index (HIA). Cadmium, copper, lead and zinc, and the sum of DDT levels in soil samples were below maximum residue levels (MRLs). The MRLs of lead and DDD were exceeded in milk and cheese samples from all the 3 areas. The MRLs of copper and zinc were exceeded in cheese samples from area 2 and 3. HQs >10 for lead indicates increased risk, while HQ > 1 for copper and sum of DDT indicates moderate risk for both milk and cheese. By calculating the HI_A, we identified a moderate and increase risk for nephrotoxicity, hepatotoxicity, hematotoxicity, cardiotoxicity and reproduction toxicity after consumption of the dairy products from the 3 areas.

A systematic review and meta-analysis of lead and cadmium concentrations in cow milk in Iran and human health risk assessment

The aim of the current research was to systematically review and summarize the studies that evaluated the concentration of lead (Pb) and cadmium (Cd) in cow milk in different regions of Iran and to perform a meta-analysis of the findings. Moreover, the non-carcinogenic and carcinogenic risks of Pb and Cd through milk consumption in adult and child consumers were assessed. As a result of a systematic search in the international and national databases between January 2008 and October 2018, 17 reports involving 1874 samples were incorporated in our study for meta-analysis. The pooled concentrations of Pb and Cd were estimated to be 13.95 μg mL^-1 (95% CI 9.72-18.11 μg mL^-1) and 3.55 μg mL^-1 (95% CI - 2.38-9.48 μg mL^-1), respectively, which were lower than the WHO/FAO and national standard limits. The estimated weekly intake (EWI) of Pb and Cd through consuming milk was 16.65 and 7 μg day^-1 for adults of 70 kg and 45 and 34 μg day^-1 for children of 26 kg, respectively, which was well below the risk values set by Joint FAO/WHO Expert Committee on Food Additives (JECFA). The maximum target hazard quotient values (THQs) of Pb and Cd were 5.55E-5 and 5.55E-5 for adults and 5.55E-5 and 5.55E-5 for children, respectively, which were lower than 1 value, suggesting that Iranian consumers are not exposed to non-carcinogenic risk through consuming milk. Moreover, the incremental lifetime cancer risk (ILCR) of Pb estimated to be 2.96E-04 in adults and 1.0E-03 in children, indicating that consumers in Iran are at threshold carcinogenic risk of Pb through consuming milk (ILCR > 10^-4). Therefore, planning and policy making for the sustainable reduction of these toxic metals in milk, particularly in industrial regions of Iran, are crucial.

Determination of some element levels in various kinds of cow's milk processed in different ways

This study aimed to measure zinc (Zn), selenium (Se), copper (Cu), iron (Fe), chromium (Cr), nickel (Ni), lead (Pb), cadmium (Cd), arsenic (As), and aluminum (Al) in whole, semi-skimmed, skimmed, organic, fruit-flavored (strawberry, banana, and cocoa), pasteurized, and raw cows' milk. The samples were collected from sterilized and pasteurized milk processed in different ways in Ankara; the milk was kept in refrigerated raw milk storage tanks on dairy farms. Ninety samples were collected, and there were ten samples in each group. Analyses were performed using inductively coupled plasma-mass spectrometry. Lead and Cd were not found in any samples, while Zn was observed in all samples. The element with the highest frequency of occurrence was Zn, followed by Cr = As> Al > Se > Fe > Ni > Cu > Pb = Cd, in decreasing order. The lowest concentration among the essential elements was seen in Cu. Aluminum and As were found in 85% and 94.45% of the samples, respectively. However, the present concentrations were below the level of a probable negative effect. It was found that the concentrations of elements in milk showed statistically significant differences, depending on the milk type. It is recommended that low-quality materials not be used in the preparation of milk; the element concentrations in milk and the feed and water consumed by animals should be controlled regularly, and the animals should not be pastured near industrial and traffic sites to protect public health.

Determination of the content of Pb, Cd, Cu, Zn in dairy products from various regions of Poland

The toxicity of heavy metals and their capacity for accumulation in the human organism make it necessary to conduct monitoring of their concentration in food. The objective of the study was to determine the content of lead, cadmium, copper and zinc in milk and dairy products from various regions of Poland: the Lublin Region, Podlasie, Podkarpacie, and Silesia. The study showed the presence of the analysed heavy metals in most of the products. The content of lead was related to the level of industrialisation of a region. Higher levels of Pb were found in products from Silesia than in those from the other regions. The study revealed the presence of cadmium in 50% of the samples. Its content varied in range from 0.0067 to 0.0058 mg/kg. The levels of Cu and Zn concentration in the analysed products were within broad ranges, from 0.0015 to 4.94 mg/kg and from 0.01 to 56.44 mg/kg, respectively. In the case of all analysed elements an increase in their concentration was noted in cheese spreads and cottage cheeses. No relationship was found between the content of heavy metals in the analysed products, and the region of their origin.

Exposure to Metals from Artisanal Cheeses Made with Goat's Milk

Cheeses are an important source of essential elements. Nevertheless, the level of some metals could pose a health risk. Therefore, the concentration of trace elements and toxic metals (Cr, Cu, Li, Ni, Sr, Pb, Cd, and Al) has been determined in artisanal cheeses from different geographical locations, and the intake of these metals from cheese consumption has been evaluated. The metal concentration was determined in a total of 90 cheese samples from different locations by using inductively coupled plasma atomic emission spectroscopy. The highest concentration of Al (35.1 ± 4.42 mg/kg, wet weight) was found in artisanal cheeses from Zamora (Spain), followed by Sr (6.85 ± 0.35 mg/kg, wet weight) in artisanal cheeses from Cadiz (Spain). A daily consumption of 23.2 g of cheese provides a significant dietary contribution for Al of 0.82% of its tolerable weekly intake of 1 mg/kg of body weight per week. Canary Islands cheeses have a higher metal content than the non-Canary cheese, which could be because of the volcanic characteristics of the island soils. The intake of toxic metals and trace elements poses no risk to the health of adults.

Lead and cadmium levels in raw bovine milk and dietary risk assessment in areas near petroleum extraction industries

Oil fields are a source of heavy metal pollution, but few studies have evaluated its impact on the intake of these contaminants through milk, an important food especially for children. From February 2015 to 2016, 118 samples of raw cow's milk, 14 of fodder and 8 of water in Southwest Iran were collected from farms close to oil fields or related industries. Lead (Pb) and cadmium (Cd) levels were evaluated by graphite furnace atomic absorption spectrometry. Mean±SE in milk and fodder were 47.0±3.9 and 54.0±6.9μg/kg for Pb, and 4.7±1.0 and 3.5±1.3μg/kg for Cd. No Pb or Cd was detected in water. Most milk samples (82.2%) for Pb were above the permissible limits (20μg/kg). Exposure to Pb and Cd from milk consumption was calculated in two scenarios: mean and maximum exposure for the age range of 2-90years. The intake of an average Iranian adult (25years, 60kg b. w., 0.14kg milk/day) would be 6.6μg Pb and 0.66μg Cd/day (WI of 46.2 and 4.6μg, respectively), well below the risk values proposed by some international organizations, even in the maximum exposure scenario. However, Pb exposure for infants and toddlers may be closer to the risk values, since milk and milk products could be the main contributor to Cd and Pb, and small children consume 2-3 times more food than adults relative to their body weight. The risk of Pb and Cd exposure through milk close to oil fields should be considered and a monitoring plan for these contaminants is strongly recommended.

Occurrence of selected metals in feed and sheep´s milk from areas with different environmental burden

The content of selected essential elements and toxic metals in feed and sheep's milk from areas with different parts of Slovak Republic was analyzed. Region of Novoť (undisturbed environment; North Slovakia) and region of Klátova Nová Ves (widely disturbed environment; Western Slovakia) were under investigation. Eleven metals have been analyzed (essential elements - calcium, zinc, selenium, iron, magnesium, copper; toxic elements - arsenic, mercury, lead, cadmium, nickel). Samples of feeds and milk were collected five-times during the year (spring and autumn season). Analyses of samples were performed by certified testing laboratory Eurofins Bel/Novamann (Nové Zámky, Slovak Republic). Analyses were performed by routine methods, according to the valid methodologies. The results showed significantly higher content of selected essential elements in feed in spring season from area with widely disturbed environment (Klátova Nová Ves). Significantly higher content of essential elements in milk was on farm of Novoť (undisturbed environment). Occurrence of toxic metals in feed from area with widely disturbed environment in spring season did not affect their content in milk. It can be concluded, that the use of milk of sheep from these areas for direct use or for dairy products processing is appropriate, safe and poses no health risk for the consumers.

Direct determination of Pb in raw milk by graphite furnace atomic absorption spectrometry (GF AAS) with electrothermal atomization sampling from slurries

Milk is an important food in the human diet due to its physico-chemical composition; therefore, it is necessary to monitor contamination by toxic metals such as Pb. Milk sample slurries were prepared using Triton X-100 and nitric acid for direct analysis of Pb using graphite furnace atomic absorption spectrometry - GF AAS. After dilution of the slurries, 10.00µl were directly introduced into the pyrolytic graphite tube without use of a chemical modifier, which acts as an advantage considering this type of matrix. The limits of detection and quantification were 0.64 and 2.14µgl^-1, respectively. The figures of merit studied showed that the proposed methodology without pretreatment of the raw milk sample and using external standard calibration is suitable. The methodology was applied in milk samples from the Guarapuava region, in Paraná State (Brazil) and Pb concentrations ranged from 2.12 to 37.36µgl^-1.

Estimated daily intake and health risk of heavy metals by consumption of milk

Cd, Co, Pb, Cu and Ni were analysed in 480 milk samples by flame atomic absorption spectrophotometry. Mean concentrations were 0.001, 0.061, 0.014, 0.738 and 0.028 mg/kg, respectively. Mean concentration of Cd was very low, whereas Cu exceeded the maximum limits established by the Codex Alimentarius. In some areas, the Pb concentration exceeded the maximum limit as set by the Codex Alimentarius. The highest estimated daily intake (EDI) of Cu calculated for male infants (1-3 year) was 33.534 µg/kg bw/day, while the lowest EDI was recorded for Cd (0.004 µg/kg bw/day) in adult females above 16 years. The results suggested that Cu and Pb from milk in the investigated areas may pose a health risk to the consumers.

Validation of methods for H, C, N and S stable isotopes and elemental analysis of cheese: results of an international collaborative study

RATIONALE

PDO cheeses, such as Parmigiano Reggiano and Grana Padano, which cost more than double generic similar cheeses, must be protected against mislabelling. The aim of this study was to validate the methods for the isotopic and elemental analysis of cheese, in order to support official recognition of their use in authenticity assessment.

METHODS

An international collaborative study based on blind duplicates of seven hard cheeses was performed according to the IUPAC protocol and ISO Standards 5725/2004 and 13528/2005. The H, C, N and S stable isotope ratios of defatted cheese determined using Isotope Ratio Mass Spectrometry (IRMS) and the content of Li, Na, Mn, Fe, Cu, Se, Rb, Sr, Mo, Ba, Re, Bi, U in cheese after acid microwave digestion using Inductively Coupled Plasma Mass Spectrometry or Optical Emission Spectrometry (ICP-MS or -OES) were measured in 13 different laboratories.

RESULTS

The average standard deviations of repeatability (sr) and reproducibility (sR) were 0.1 and 0.2 ‰ for δ(13)C values, 0.1 and 0.3 ‰ for δ(15)N values, 2 and 3 ‰ for δ(2)H values, and 0.4 and 0.6 ‰ for δ(34)S values, thus comparable with results of official methods and the literature for other food matrices. For elemental data, the average RSDr and RSDR values ranged between 2 and 11% and between 9 and 28%, respectively, consistent with methods reported by the FDA and in the literature for cheese.

CONCLUSIONS

The validation data obtained here can be submitted to the standardisation agencies to obtain official recognition for the methods, which is fundamental when they are used in commercial disputes and legal debates.

The intracellular source, composition and regulatory functions of nanosized vesicles from bovine milk-serum

A hypothesis that the source of milk-serum derived vesicles (MSDVs) is the Golgi apparatus (GA) was examined.

Determination of heavy metals in milk and fermented milk products by potentiometric stripping analysis with constant inverse current in the analytical step

A simple and rapid method for the direct determination of cadmium, lead and copper in milk and fermented milk products by potentiometric stripping analysis (PSA) with oxygen as an oxidant and with inverse current imposed through the stripping step is described. For the more selective metals determination a samples pretreatment by the microwave acid extraction was applied. Due to the significant increase of the modified technique sensitivity, the detection limits of 0.30, 1.7 and 3.8 μg/l were obtained, for cadmium, lead and copper, respectively. The method accuracy was confirmed by analysing the standard reference material (SRM 1577 b). The contents of cadmium, lead and copper in milk samples were in the range of 2.13-4.82, 54.3-95.2 and 112.2-124.7 μg/kg, respectively, whereas in the samples of fermented milk products in the range of 6.30-24.1, 210.1-463.6 and 260.0-320.7 μg/kg, respectively.

Lead and cadmium concentrations in goat, cow, sheep, and buffalo milks from different regions of Iran

In total, 137 goat, cow, sheep, and buffalo milk samples were collected in different regions of Iran and analysed to determine concentrations of lead and cadmium by a graphite furnace atomic absorption spectrometric method. The mean recovery of the analytical method was 96.3% and 104% for cadmium and lead, respectively. The mean lead and cadmium contents obtained from 137 samples were 1.93 ± 1.48 (range: 0.18-6.11 ng/ml) and 9.51 ± 4.93 ng/ml (range: 1.84 ng/ml-30.50 ng/ml), respectively. Lead concentration in 8.1% of sheep and 1.9% of cow milk samples was higher than the newly established Codex standard. The mean concentrations of cadmium and lead in animals aged ≤ 3 years (n=80; 1.40 ± 1.05 ng/ml and 7.91 ± 3.60 ng/ml, respectively) were lower than in animals aged >3 years (n=58; 2.69 ± 1.67 ng/ml and 11.8 ± 5.71 ng/ml, respectively).