Analysis of minor and trace elements in milk and yogurts by inductively coupled plasma-mass spectrometry (ICP-MS)

Highly sensitive aggregation-induced electrochemiluminescence sensor for cadmium detection in Ganoderma lucidum

Cadmium (Cd) pollution poses a major threat to food safety. Sensitive detection of Cd2+ is of great significance for the life health. Herein, an aggregation-induced electrochemiluminescence (AIECL) sensor based on polymer dots (Pdots) is designed for Cd2+ detection. Through linkage of Cd2+ aptamer containing black hole quencher (BHQ) with Pdots, a signal "off" probe was achieved. In the presence of Cd2+, the BHQ moiety is released from Pdots and the ECL signal of Pdots is recovery. Such sensor exhibits excellent detection capability for Cd2+, with low detection limit of 0.006 ppb. More importantly, the sensor is applied for the quantitative analysis of Cd2+ in Ganoderma lucidum, and the results coincide well with the golden standard of ICP-MS. This study presents a facile and reliable methodology for the sensitive detection of cadmium, and demonstrates its potentials applying in food safety and environmental monitoring.

Development and biochemical characterization of freeze-dried guava powder fortified with Lactobacillus plantarum

Guava (Psidium guajava L.) is one of the most nutrient-dense fruits, which is native to tropical and subtropical regions of the world. The processing of value-added products from guava has not been carried out on a scale similar to some other fruits, which offers an opportunity to fully exploit the potential of this fruit, such as guava-based nutraceutical food products. The objectives of the present study were to develop freeze-dried guava powders (FDGPs) from two guava varieties (white and pink) and characterize their physico-chemical and nutritional properties. FDGP was also incorporated with probiotic strains of Lactobacillus plantarum, to develop a healthy nutraceutical probiotic supplement. Functional groups assessed by Fourier transform infrared (FTIR) spectroscopy exhibited the existence of strong C-Br stretch, O-H stretch, and C = C stretch vibrations; however, scanning electron micrograms (SEMs) showed the flaky structure indicating the presence of starch, dietary fibers, and esterified groups of pectin. Significant mineral concentrations (mg/100 g) of potassi-um (323-362), magnesium (26.2-28.8), zinc (0.43-0.51), and iron (0.52-0.63) were observed in FDGPs. The FDGP samples from both guava varieties had high levels of crude fiber (43.94-46.29%), vitamin C (2.27-2.49 mg/g), and phenolic compounds (57.50-61.86 mg GAE/g) as well as significant antioxidant properties. Fortification of FDGP with L. plantarum strains produced significant results in terms of probiotic viability that was nearly maintained at 108 CFU/g up to 60 days in the final product. The viability of probiotics proved that FDGP is a good carrier of prebiotics and can be utilized as a potent probiotic supplement.

Spatial and Bioaccumulation of Heavy Metals in a Sheep-Based Food System: Implications for Human Health

Heavy metal contamination in agricultural soils presents serious environmental and health risks. This study assessed the bioaccumulation and spatial distribution of nickel, cadmium, zinc, lead, and copper within a sheep-based food chain in the Baia Mare region, Romania, which includes soil, green grass, sheep serum, and dairy products. Using inductively coupled plasma mass spectrometry (ICP-MS), we analyzed the concentrations of these metals and calculated bioconcentration factors (BCFs) to evaluate their transfer through trophic levels. Spatial analysis revealed that copper (up to 2528.20 mg/kg) and zinc (up to 1821.40 mg/kg) exceeded permissible limits, particularly near former mining sites. Elevated lead (807.59 mg/kg) and cadmium (2.94 mg/kg) were observed in industrial areas, while nickel and cobalt showed lower concentrations, but with localized peaks. Zinc was the most abundant metal in grass, while cadmium transferred efficiently to milk and cheese, raising potential health concerns. The results underscore the complex interplay between soil properties, contamination sources, and biological processes in heavy metal accumulation. These findings highlight the importance of continuous monitoring, risk assessment, and mitigation strategies to protect public health from potential exposure through contaminated dairy products.

Toxic Elements in Sheep Milk, Whey, and Cheese from the Environmentally Burdened Area in Eastern Slovakia and Health Risk Assessment with Different Scenarios of Their Consumption

The study aimed to determine the content of 17 elements (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sb, Se, Sr, and Zn) in samples of sheep milk, cheese, and whey (36 samples in total) collected from a farm in an environmentally burdened area due to the long-term mining and industrial activity in Slovakia as well as to determine the possible risk of consumption via health risk assessment calculations. Consumption of 120 g of milk, 500 g of milk, 20 g of cheese, and 100 g of cheese were used in calculations for children and adults, respectively. According to the results, concentrations of four elements are controversial. Lead concentrations in all types of samples exceeded the maximum permissible lead limit in milk set by European Union legislation. The content of Se and As is problematic for children's consumption, and the target hazard quotient for As and Al is higher than one (considered potentially not safe) in all scenarios. According to the target system approach, lead concentrations in milk and cheese could adversely influence the nervous system and kidneys of adults' and children's developmental and reproductive systems. Considering the worst-case scenario, consuming sheep milk and cheese from the monitored areas could represent a risk and be potentially harmful to human health, mainly for children. However, further monitoring of the levels of elements and concentrations in environmentally burdened areas and more robust data on consumption are needed.

Assessment of essential and potentially toxic metals in raw cow milk from Mukaturi town, Oromia Regional State, Ethiopia

Cow milk is a complete and highly nutritious source of food for humans. However, the quality of milk products has become a significant health concern for consumers, particularly infants and children, in many developing nations, including Ethiopia. The objective of this study was to determine the heavy metal levels in raw cow milk collected from dairy producers and collection centers in Mukaturi town, Ethiopia. Sixty raw cow milk samples (40.0 milk samples from dairy farms and 20.0 milk samples from collection centers) were randomly collected and digested using a mixture of nitric acid (HNO3), hydrogen peroxide (H2O2) and perchloric acid (HClO4) on a hot plate. The amounts of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the milk samples were determined using inductively coupled plasma atomic emission spectroscopy (ICP-OES). The findings showed that the average concentrations of Pb (2.31 ± 0.127), Fe (0.566 ± 0.130), Ni (0.210 ± 0.0189), Cd (0.0372 ± 0.0230), Cr (0.369 ± 0.0162), and Co (0.225 ± 0.0150) in mgL-1 were higher than the allowable limits. This could pose a health risk to the public. However, the concentrations of Mn (0.044 ± 0.0369), Cu (0.195 ± 0.0450) and Zn (2.90 ± 0.0570) in mg L-1 were lower than or within the recommended limits and cannot pose any threat to consumers. The validity of the digestion processes was checked by the recovery test. The percentage recoveries of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were found to be in the range of 80.7-122 %, which is within the acceptable range. Therefore, special attention should be given to the continuous monitoring of heavy metal levels in raw milk among dairy producers and collection centers to minimize economic losses and the risk to consumer safety.

Assessing the Health Risk and Trophic Transfer of Lead and Cadmium in Dairy Farming Systems in the Mantaro Catchment, Central Andes of Peru

This study investigated lead (Pb) and cadmium (Cd) transfer in three dairy farming areas in the Mantaro river headwaters in the central Peruvian Andes and at varying distances from the mining complex at La Oroya. At each of these sites, the transfer of trace metals from the soil to raw milk was estimated, and a hazard assessment for lead and cadmium was carried out in scenarios of minimum, average, and maximum milk consumption in a Peruvian population aged 2-85. Pb and Cd were quantified by flame atomic absorption spectrometry. Significantly, the concentrations of lead and cadmium were found to exceed the maximum limits recommended by the World Health Organization, with a positive geospatial trend correlated with the distance from mining activity. Both Pb and Cd were found to be transferred through the soil-pasture-milk pathway, with the primary source of Cd being phosphate-based fertilizers used in pasture improvement. Pb was found to be the most significant contributor to the Hazard Index (HI) with those under 19 years of age and over 60 recording an HI of >1, with infants being the most vulnerable group due to their greater milk consumption in relation to their body weight. A marginal increase in contamination was observed in the dry season, indicating the need for studies to be expanded over several annual cycles.

Measurement of 90Sr and 87Sr/86Sr isotope ratio in Japanese cow milk sample using thermal ionization mass spectrometry

The pure beta emitter 90Sr (T1/2 = 28.8y) is a typical contaminant released by nuclear accidents and nuclear explosions. In the event of a nuclear disaster, it is crucial to identify radioactive pollutants quickly, to expedite the public's awareness of radiation exposure. In this work, a rapid 90Sr analysis protocol using thermal ionization mass spectrometry (TIMS) was developed for milk samples. With the improved sample preparation, Sr separation, and a newly developed TIMS method, 18 milk samples can be analyzed in less than 30 h and only 1 mL of cow milk is required for the complete analysis. The minimum detectable activity concentration of 90Sr is affected by the stable Sr concentration therefore, it is around 500 mBq·kg-1 (∼100ag·g-1). Additionally, 87Sr/86Sr isotope ratios (0.71518(9)-0.74132(4)) were determined for the first time in Japanese cow milk samples.

Concentration of heavy metals in pasteurized and sterilized milk and health risk assessment across the globe: A systematic review

OBJECTIVE

Although milk and dairy products are almost complete food, they can contain toxic heavy elements with potential hazards for consumers. This review aims to provide a comprehensive report on the occurrence, concentration, and health risks of selected heavy metals in pasteurized and sterilized milk recorded worldwide.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was used to develop this systematic review. Databases included the Web of Knowledge, Scopus, Scientific Information Database, Google Scholar, and PubMed from inception until January 2023. Keywords related to the terms "Heavy metals", "Arsenic" and "Pasteurized and sterilized milk" and "Risk Assessment" were used. The potential health risks to human health from milk daily consumption were estimated using extracted data on heavy metals concentration based on metal estimated daily intake, target hazard quotient, and carcinogenic risk.

RESULTS

A total of 48 potentially relevant articles with data on 981 milk samples were included in the systematic review. Atomic Absorption Spectroscopy, atomic absorption spectroscopy, inductively coupled plasma-mass spectrometry, and inductively coupled plasma-optical emission spectrometry were the most common valid methods to measure heavy metals in milk samples. Following the initial evaluation, Cu, Cd, Zn, and Pb were the most contaminants, which exceeded the maximum permissible criteria in 94%, 67%, 62%, and 46% of the milk samples tested. Relying on target hazard quotient and carcinogenic risk results, milk consumers in 33(68.75%) and 7 (14.5%) studies were exposed to moderate to high levels of carcinogenic and non-carcinogenic risk, respectively. The highest level of risk is due to the consumption of pasteurized and sterilized milk detected in Pakistan, Brazil, Egypt, Slovakia, and Turkey.

CONCLUSION

The elevated levels of heavy metals in milk samples, especially Pb and Cd is a public health concern; therefore, maximum control and strict regulations must be adopted to decrease heavy metals contaminants in the dairy industry. Further studies are required to develop safe milk processing and handling methods for the decontamination of heavy metals in milk and its products.

Heavy metal contamination and health risk assessment of horticultural crops in two sub-cities of Addis Ababa, Ethiopia

This particular study was aimed to establish the level of heavy metals in different horticultural crops cultivated by irrigation and the soil in two sub-cities of Addis Ababa, Ethiopia, and quantitatively assess the health treat they pose for the consumer. A total of 151 vegetable samples comprised of lettuce (Lactuca sativa), cabbage (Brassica oleracea var. capitate), cucumber (Cucumis sativus), potato (Solanum tuberosum), parsley (Petroselinum crispum), Swiss chard (Beta vulgaris subsp. vulgaris), beetroot (Beta vulgaris), green onion (Allium porrum L.) and 28 soil samples were collected for this study. Six toxic elements were analyzed using microwave plasma atomic emission spectroscopy (MP-AES) after microwave assisted digestion of the samples. The concentrations of examined trace elements in vegetables (mg/kg) were found in the range of 5.50-93.00 for zinc; below detection limit (BDL)- 18.50 for copper; BDL-2.50 for nickel; BDL-17.00 for lead; 5.00-4256.50 for manganese and 22.00-8708.00 for iron. Considering the mean Pb content values, all vegetables exceeded the maximum permissible level set by the joint FAO/WHO commission in both irrigation sites. In case of Mn parsley, swiss chard, and green onion all from site two exceeded the maximum allowable values. With the exception of potato from irrigation site one, all vegetables exceeded the maximum permissible limit set for Fe concentration and out of which parsley, swiss chard, and green onion, all from site two, exceeded by more than double amount. The same trend is observed for the concentration of Mn and Fe in the soil samples. In fact, in both irrigation sites their concentration exceeded the allowable limits set by United Nation Environment Program (UNEP) for agricultural soils. The metal pollution load index revealed that in most of the vegetables studied the overall pollution load of trace metals were higher in Kolfe Keranyo irrigation site. The risk assessment study using indices like estimation of daily/weekly dietary exposure, hazard quotient and metal pollution load index all suggested consumption of the studied vegetables poses a significant health risk for the consumer. For adults the calculated target hazard quotient for the trace element Pb is higher than 1 (one) for all of studied vegetables ranging from 11.086 (cucumber) to 17.881 (beetroot) with a 98.216% and 98.464% contribution to the hazard indices, respectively. For a child consumer, Mn showed a higher target hazard quotient vales ranged from 0.0107 (cucumber) to 0.0495 (green onion) with a 70.86% and 88.85% contribution to the total hazard indices, respectively. The soil pollution indices also indicated that the degree of metal enrichment in soils and sediments are higher than the allowable limits. Therefore, a prompt action is required to curb the problem and ensure the public safety along the food system line.

Influence of Geographical Origin on Isotopic and Elemental Compositions of Pork Meat

Pigs are a primary source of meat, accounting for over 30% of global consumption. Consumers' preferences are determined by health considerations, paying more attention to foodstuffs quality, animal welfare, place of origin, and swine feeding regime, and being willing to pay a higher price for a product from a certain geographical region. In this study, the isotopic fingerprints (δ2H, δ18O, and δ13C) and 29 elements of loin pork meat samples were corroborated with chemometric methods to obtain the most important variables that could classify the samples' geographical origin. δ2H and δ18O values ranged from -71.0 to -21.2‱, and from -9.3 to -2.8‱, respectively. The contents of macro- and micro-essential elements are presented in the following order: K > Na > Mg > Ca > Zn > Fe > Cu > Cr. The LDA model assigned in the initial classification showed 91.4% separation of samples, while for the cross-validation procedure, a percentage of 90% was obtained. δ2H, K, Rb, and Pd were identified as the most representative parameters to differentiate the pork meat samples coming from Romania vs. those from abroad. The mean values of metal concentrations were used to estimate the potential health risks associated with the consumption of pork meat The results showed that none of the analyzed metals (As, Cd, Sn, Pb, Cu, and Zn) pose a carcinogenic risk.

Factors Affecting Toxic and Essential Trace Element Concentrations in Cow's Milk Produced in the State of Pernambuco, Brazil

The aim of this study was to provide information on the levels of toxic (Cd and Pb) and essential (Cu, Fe, and Zn) elements in cow's milk produced in the State of Pernambuco (Brazil). A total of 142 samples of raw milk were collected, and the concentrations of essential and toxic elements were determined using inductively coupled plasma-optical emission spectrometry. In almost 30% of the samples analyzed, the Pb content exceeded the maximum level established in the Brazilian legislation (0.05 mg/L). By contrast, in all the samples, the Cd content was below the maximum allowable level (0.02 mg/L). The essential trace elements Cu, Fe, and Zn were generally present at lower concentrations than reported in other studies and can be considered within the deficient range for cow's milk. Statistical and chemometric procedures were used to evaluate the main factors influencing the metal concentrations (proximity to major roads, presence of effluents, and milking method). The study findings demonstrate that the proximity of the farms to major roads influences the concentrations of Cd, Pb, and Cu and that this is the main factor explaining the Pb content of milk. In addition, the presence of effluents influenced the concentrations of Cu, while no relationship between the metal content and the milking method was observed. Thus, in accordance with the study findings, the consumption of cow's milk produced in the region can be considered a risk to public health due to the high concentrations of Pb and the low concentrations of other essential minerals such as Cu, Zn, and Fe in some of the milk samples.

Elemental Analysis of Kimchi Cabbage Leaves, Roots, and Soil and Its Potential Impact on Human Health

In view of their rich mineral content and flavor, kimchi cabbage leaves and roots have high nutritional and medicinal values. In this study, we quantified major nutrient (Ca, Cu, Fe, K, Mg, Na, and Zn), trace (B, Be, Bi, Co, Ga, Li, Ni, Se, Sr, V, and Cr), and toxic (Pb, Cd, Tl, and In) elements in kimchi cabbage cultivation soil, leaves, and roots. The analysis method relied on inductively coupled plasma-optical emission spectrometry for major nutrient elements and inductively coupled plasma-mass spectrometry for trace and toxic elements and complied with the Association of Official Analytical Chemists (AOAC) guidelines. Kimchi cabbage leaves and roots featured high contents of K, B, and Be, while the contents of all toxic elements in all samples were below the WHO-stipulated threshold values and therefore did not pose any health risks. The distribution of elements was characterized by heat map analysis and linear discriminant analysis to reveal independent separation according to the content of each element. The analysis confirmed that there was a difference in content between the groups and that each group was independently distributed. This study may contribute to a better understanding of the complex relationships between plant physiology, cultivation condition, and human health.

A ratiometric electrochemical sensor for detecting lead in fish based on the synergy of semi-complementary aptamer pairs and Ag nanowires@zeolitic imidazolate framework-8

This work describes the synergistic application of semi-complementary aptamer pairs and signals on-off ratio strategies on glassy carbon electrodes (GCE) for detecting lead ions (Pb²⁺) in fish. Gold nanoparticles (AuPNs) as the electrode substrate can provide added binding sites for the aptamers and improve the conductivity of the electrodes. Pb²⁺ aptamers containing ferrocene (Fc) molecules act as molecular recognizers in the sensing system. In the presence of target ions, Fc signals are affected by conformational changes of the aptamer. The "Ag nanowires@zeolitic imidazolate framework-8 with methylene blue (AgNWs@ZIF-8/MB)" can be semi-complementary to the Pb²⁺ aptamer after binding to single-stranded DNA (S₁). However, S₁/AgNWs@ZIF-8/MB self-assembled with Pb²⁺ aptamer (Apt) by hybridization incubation was quickly replaced by Pb²⁺ competitively, resulting in the loss of methylene blue (MB) signaling molecules. Hence, the internal reference signal (MB) and conformation change signal (Fc) comprise the ratio sensing system well. Morphology, spectroscopy, and electrochemistry methods have validated the modification and sensing behaviors. The used Apt has made considerable progress in analytical performance. In interference studies and stability checks, the ratio measurement signal I_Fc/I_MB is a more reliable signal than the single signal readout. Following a log-linear relationship, this sensor provides a wide linear range. Furthermore, the proposed sensor can be used to determine Pb²⁺ in fish samples, and the results agree with those obtained using ICP-MS and recovery tests.

Selective determination of cadmium and lead ions in different food samples by poly (riboflavin)/carbon black-modified glassy carbon electrode

In this research, a poly (riboflavin)/carbon black-modified glassy carbon electrode (PRF/CB/GCE) is introduced as a novel electrochemical sensor toward Cd²⁺ and Pb²⁺ simultaneous measurement in presence of bismuth ions, applying differential pulse anodic stripping voltammetry (DPASV). Regarding the optimized conditions, the linear ranges were achieved from 0.5 to 600 nM for Cd²⁺ and Pb²⁺. The detection limit (LOD) was found to be 0.16 nM for Cd²⁺ and 0.13 nM for Pb²⁺. In order to perform the technique in real application, the proposed electrode was used to simultaneously detect ions in rice, honey, and vegetable samples with satisfactory recoveries - indicating that the sensor possesses good practicability to determine Cd²⁺ and Pb²⁺. Moreover, an atomic absorption spectrometry (AAS) was used in order to detect the concentration of ions as a reference technique in rice, honey, and vegetable samples.

Selenium in selected samples of infant formulas and milk commercialized in Belgium and Brazil: Total content, speciation and estimated intake

Total selenium (Se) and Se species concentrations were determined in 50 infant formulas and milk samples commercialized in Brazil and Belgium. Infant formula categories were starter, follow-up, specialized and plant-based (soy and rice), while milk samples included whole, skimmed, semi-skimmed and plant-based products. Total Se content was determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), after microwave digestion. An enzymatic extraction method was applied to evaluate the Se species, mostly selenomethionine (SeMet), Se(IV) and Se(VI), through High Performance Liquid Chromatography coupled to ICP-MS (LC-ICP-MS). Starters and follow-up samples presented the highest total Se concentrations and values up to 30 µg/kg were observed in the reconstituted product. The lowest level (below the LOQ = 10 µg/kg) was verified in an anti-regurgitation specialized formula. The relative agreement between the measured total Se and the Se content declared on the label varied from 55 % to 317 %. Concentrations in infant formulas were not markedly different from concentrations in milk except for rice and oat milk samples that showed values below the LOQ. SeMet was the main species found in milks, while in infant formulas the species concentrations varied according to the product. The daily intake (DI) of Se via infant formula consumption was calculated and compared with the Adequate Intake (AI) value and the Dietary Reference Intake (DRI) established by the EFSA NDA Panel and ANVISA, respectively. Estimated maximum intakes of total Se obtained for reconstituted infant formula were 40.6 mg/day, corresponding to 400 % and 202 % of the DRI and AI, respectively.

The assessment of lead concentration in raw milk collected from some major dairy farms in Iran and evaluation of associated health risk

Milk is one of the most consumed sources among people, especially children. hence, its contamination with heavy metals can pose a serious risk to children. Therefore, this study aimed to measure the lead concentration as one of the most dangerous heavy metals in the raw milk of several major animal husbandries in Tehran province from Iran. A total of 57 raw milk samples were collected from different regions of Tehran province. The lead contents were measured using a graphite furnace atomic absorption spectrometer. To evaluate the risk of the samples and hazard quotient (HQ) were calculated. The results showed that HQ for all samples was lower than 1 which was found within the acceptable level. Because the absorption of Pb is higher in children and this metal has a cumulative property in the body, even its small weekly intake can be dangerous in long-term consumption.

Dataset of pollutants in organic and non-organic food

Organic and non-organic equivalent corresponding type of foods were assessed for pollutants, polycyclic aromatic hydrocarbons (PAHs), pesticides and heavy metals. In total, 35 samples of sausages and cheeses were tested from three western European countries, Spain, France, and Germany. These samples were chosen because they are meat and milk products presenting some bioaccumulation capacity. Petroleum residues were demonstrated in pesticide formulants. These include polycyclic aromatic hydrocarbons (PAHs) and metals. We measured in these human foods 800 pesticides, 24 PAHs, using accredited methods, as well as eleven metals and elements. Pesticides’ measurements were performed either by gas or liquid chromatography, followed by mass spectrometry, according to regulatory standard methods, that were measured over the threshold of 10 μg/kg for this reason. This could be insufficient to detect all toxic contaminations. Metals were analysed by high frequency induced plasma emission spectrometry and mass spectrometry after pressurized digestion. PAHs were assessed by gas and/or high-performance liquid chromatography with reverse phase polarity and if necessary double mass spectrometry. The raw data are summarized in Tables 1 and 2. The dataset can be reused for statistical analyses by the scientific community to evidence food pollution and to be compared with other measurements.

Intra-regional classification of Codonopsis Radix produced in Gansu province (China) by multi-elemental analysis and chemometric tools

Multi-elemental analysis is widely used to identify the geographical origins of plants. The purpose of this study was to explore the feasibility of combining chemometrics with multi-element analysis for classification of Codonopsis Radix from different producing regions of Gansu province (China). A total of 117 Codonopsis Radix samples from 7 counties of Gansu province were collected. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of 28 elements (³⁹ K, ²⁴ Mg, ⁴⁴Ca, ²⁷Al, ¹³⁷Ba, ⁵⁷Fe, ²³Na, ⁸⁸Sr, ⁵⁵Mn, ⁶⁶Zn, ⁶⁵Cu, ⁸⁵Rb, ⁶¹Ni, ⁵³Cr, ⁵¹ V, ⁷Li, ²⁰⁸Pb, ⁵⁹Co, ⁷⁵As, ¹³³Cs, ⁷¹ Ga, ⁷⁷Se, ²⁰⁵Tl, ¹¹⁴Cd, ²³⁸U, ¹⁰⁷Ag, ⁴Be and ²⁰²Hg). Among macro elements, ³⁹ K showed the highest level, whereas ²³Na was found to have the lowest content value. Micro elements showed the concentrations order of: ⁸⁸Sr > ⁵⁵Mn > ⁶⁶Zn > ⁸⁵Rb > ⁶⁵Cu. Among trace elements, ⁵³Cr and ⁶¹Ni showed higher content and ⁴Be was not detected in all samples. Intra-regions differentiation was performed by principal component analysis (PCA), cluster analysis (CA) and supervised learning algorithms such as linear discriminant analysis (LDA), k-nearest neighbors (k-NN), support vector machines (SVM), and random forests (RF). Among them, the RF model performed the best with an accuracy rate of 78.79%. Multi-elemental analysis combined with RF was a reliable method to identify the origins of Codonopsis Radix in Gansu province.

The Content of Cobalt, Silver and Vanadium in Raw Cow's Milk in Croatia and Risk Assessment for Consumers

Concentrations of selected trace elements Ag, Co and V in raw milk sampled from four geographical regions in Croatia were measured. Silver, Co and V were detected above the limit of detection within the range of 9.52%-30.8%, 1.6%-12.1% and 12.4%-30.8%. Silver concentrations were not detected in milk samples from the Croatian Littoral and Mountainous Croatia (CL-MC) region. Similar Ag content was found in Southern, Eastern and Central Croatia. The lowest mean of Co and V of 33.2 and 83.8 µg kg^-1 were found in the CL-MC region while the highest of 49.8 and 136.9 µg kg^-1 was found in Central Croatia. There were no statistically significant differences in Ag, Co and V contents between the four regions. The estimated daily dietary intakes (EDI) of total mean and total 95th percentile values of Ag, Co and V showed lower values in comparison with available EFSA health-based limits.

Elemental Analysis of Solid Food Materials Using a Reliable Laser Ablation Inductively Coupled Plasma Mass Spectrometry Method

Quantification of trace and minor nutrient elements is crucial for maintaining human health. A reliable laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) method for food materials was developed by combining fine food powder (d_m < 3 μm) pellets as the external standard with an average C content as the internal standard (IS). The finer and homogeneous aerosol produced by ablating the fine powder pellets is beneficial for transportation and analyte ionization in ICP, which helps alleviate the matrix effects and improves the analytical precision and accuracy. The average C content is 39.9 ± 1.9% for plant-derived foods (n = 22) and 46.9 ± 1.1% for animal-derived foods (n = 7). The accuracy (recovery, 80-120%) and precision (RSD, 0.5-9.8%) were validated by analyzing a series of food certified reference materials. The high-throughput method is a promising alternative for routine sample analysis in food safety laboratories.

A Rapid Routine Methodology Based on Chemometrics to Evaluate the Toxicity of Commercial Infant Milks Due to Hazardous Elements

The toxicity and the health risk assessment associated to the presence of some hazardous elements (HEs) in dried (infant formula and powdered) milks due to manufacturing and packaging process, raw materials used, environmental conditions, etc. need to be determined. With this aim, a new methodology based on the combination of health risk quotients and non-supervised (as cluster analysis (CA) and principal component analysis (PCA)) chemometric techniques is proposed in this study. The methodology was exemplified using the concentration of 27 elements, some of them HEs, measured in 12 powdered milk samples produced for children and adults in Brazil and Colombia. The concentration values were obtained by inductively coupled plasma-mass spectrometry (ICP-MS) after acid microwave digestion. Elemental concentrations vary depending upon the type of milk (initiation, growing-up, follow-on milks and adult milks). However, hazard quotients (HQ) and carcinogenic risk (CR) values showed no risk associated to the presence of HEs on milks. The methodology designed made possible to conclude that adults’ milks are more characteristic of elements naturally present in milk. Children milks present major presence of trace and minor elements. Between infant milks, sample H, designed for babies between 12 and 36 months, was identified as of poor quality. Moreover, it was possible to deduce that while the fortification process applied to children powdered milks is a probable metal and metalloid source, together with the manufacturing, the skimming process is not a contamination source for milks.

Graphical abstract

Microwave-assisted digestion method using diluted nitric acid and hydrogen peroxide for the determination of major and minor elements in milk samples by ICP-OES and ICP-MS

A novel method for microwave-assisted digestion of milk samples using diluted HNO₃and H₂O₂ with a single reaction chamber was developed for elemental analysis by ICP-based techniques. The optimal conditions for digestion were 0.25 g of sample mass, 6 mL of 0.1 molL^-1HNO₃and 2 mL of 30% H₂O₂ at 250 ℃ and 160 bar. The optimized procedure resulted in low residual carbon content and residual acidity of 260 mgL^-1 and 0.06 mol L^-1, respectively. The limits of detection ranged from 0.286ոg g^-1(Ca) to 82.990ոg g^-1(Fe). In addition, the proposed method was considered an excellent green analysis method with a final score of 87 based on the analytical Eco-Scale. Finally, the method was validated and applied to the determination of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sb, Se, and Zn in milk samples from South Korea.

An electrochemiluminescence biosensor for cadmium ion based on target-induced strand displacement amplification and magnetic Fe3O4-GO nanosheets

Taking advantage of an exquisite hairpin DNA for strand displacement amplification (SDA) and the magnetic Fe₃O₄-graphene oxide nanosheets (MGN) as the carrier, an immobilization-free ECL biosensor was constructed for ultra-trace detection of Cd²⁺. Firstly, the ECL probe Ru (phen)₃²⁺ easily diffuses in the solution and reaches the electrode surface to induce strong ECL signal. This is because the pre-designed hairpin DNA is constrained by MGN in the absence of Cd²⁺. The presence of Cd²⁺ releases cDNA by binding to its corresponding aptamer, leading to removal of hairpin DNA away from the surface of MGN. In this case, SDA amplification was evoked and generated numerous dsDNA which further trapped Ru (phen)₃²⁺ in its groove. It is difficult for the embedded ECL probe to touch the electrode surface to generate ECL signal. Therefore, the concentration of Cd²⁺ was monitored according to the attenuation of ECL signal. This method showed high sensitivity to Cd²⁺ with a detection limit of 1.1 × 10^-4 ppb. Moreover, it not only avoids many condition optimizations required in the conventional SDA method, but also circumvent the modification and immobilization of DNA probe. This sensor is further applied in the detection of Cd²⁺ in the sample of traditional Chinese medicine.

Application of atmospheric pressure glow discharge generated in contact with liquids for determination of chloride and bromide in water and juice samples by optical emission spectrometry

Novel atmospheric pressure glow discharge (APGD) microplasma systems, sustained between a miniaturized flowing anode (FLA) or cathode (FLC) and a He jet, were investigated for the direct determination of Br and Cl, using optical emission spectrometry (OES). The impact of the most crucial operating parameters, i.e., the acid type and its concentration, the discharge current, the gas flow rate, and the sample flow rate, was studied for each of the proposed APGD-based systems. Under the optimized conditions, the analytical figures of merit were determined. The susceptibility to the matrix effects of both developed methods was verified as well. It was found that the mechanism of the analytes transport into the discharge likely relied on the cathode sputtering in the case of FLC-APGD and the formation of the volatile Br and Cl species for FLA-APGD. The DLs of Br and Cl were established to be relatively high, i.e., 0.15 and 1.5 mg L^-1 for FLA-APGD and 2.1 and 18 mg L^-1 for FLC-APGD. However, both studied methods turned out to be resistant to the presence of foreign ions in a sample, at relatively high concentrations. Hence, the proposed methods could be successfully applied for the determination of Br and Cl in water and juices samples and no major differences between the results obtained using the external standard calibration and the standard addition method were found.

A Simple Colorimetric Assay for Sensitive Cu2+ Detection Based on the Glutathione-Mediated Etching of MnO2 Nanosheets

In this paper, we developed a quick, economical and sensitive colorimetric strategy for copper ions (Cu²⁺) quantification via the redox response of MnO₂ nanosheets with glutathione (GSH). This reaction consumed MnO₂ nanosheets, which acted as a catalyst for the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to a blue product (oxTMB). In the presence of Cu²⁺, the GSH was catalyzed to GSSG (oxidized glutathione), and the solution changed from colorless to deep blue. Under the optimum conditions, the absorption signal of the oxidized product (oxTMB) became proportional to Cu²⁺ concentration in the range from 10 to 300 nM with a detection limit of 6.9 nM. This detection system showed high specificity for Cu²⁺. Moreover, the system has been efficaciously implemented for Cu²⁺ detection in actual tap water samples. The layered-nanostructures of MnO₂ nanosheets make it possess high chemical and thermal stability. TMB can be quickly oxidized within 10 min by the catalyzing of MnO₂ nanosheets with high oxidase-like activity. There is no need of expensive reagents, additional H₂O₂ and complicated modification processes during the colorimetric assay. Therefore, the strategy primarily based on MnO₂ nanosheets is promising for real-time, rapid and highly sensitive detection of Cu²⁺ under practical conditions.

The Occurrence, Pathways, and Risk Assessment of Heavy Metals in Raw Milk from Industrial Areas in China

This study evaluated chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) contamination in raw milk from industrial areas in China, identified the possible pathways of heavy metals from the environment to raw milk, and made a risk assessment of the consumption of heavy metals from milk consumption. The Cr, As, Cd, and Pb concentrations in raw milk, water and silage were analyzed using inductively coupled plasma mass spectrometry. The Cr and As in soil were analyzed by flame atomic absorption spectrometry and atomic fluorescence spectrometry, respectively. Cd and Pb in soil were determined by a Graphite furnace atomic absorption spectrophotometer. The Cr and As concentrations in milk from industrial areas were 2.41 ± 2.12 and 0.44 ± 0.31 μg/kg, respectively, which were significantly higher (p < 0.01) than those from non-industrial areas, which had levels of 1.10 ± 0.15 and 0.25 ± 0.09 μg/kg, respectively. Chromium was mainly transferred through the soil-silage-milk pathway, As was transferred through the water-silage-milk pathway, while Cd was mainly transferred through the soil (water)-silage-milk pathway. The contributions of each metal to the overall hazard index (HI) followed a descending order of As, Cr, Pb, and Cd, with values of 46.64%, 25.54%, 24.30%, and 3.52%, respectively. Children were at higher risk than adults.

Lead, cadmium, and aluminum in raw bovine milk: Residue level, estimated intake, and fate during artisanal dairy manufacture

OBJECTIVE

The goal of this study was to determine the levels of lead (Pb), cadmium (Cd), and aluminum (Al) in raw bovine milk. Milk consumption was used to calculate the estimated weekly intake (EWI), provisional tolerable weekly intake (PTWI), and target hazard quotient (THQ) for individuals. Metal distribution in dairy products and byproducts was studied as a result of artisanal processing.

MATERIAL AND METHODS

Seventy-five raw bovine milk samples were collected from artisanal producers in Alexandria city, West Delta, Egypt, and analyzed using the atomic absorption spectrophotometer. The effect of artisanal dairy processing on metal distribution was studied.

RESULTS

The averages of Pb, Cd, and Al in milk samples were 45.06, 4.77, and 2.93 μg/l, with 13.33% and 1.33% of analyzed samples had Pb and Al levels higher than the permissible limits, respectively. The EWI values of Pb, Cd, and Al were 1.050, 0.111, and 0.068 μg/kg body weight, which contributed to about 4.20%, 1.59%, and 0.97% from the PTWI, respectively. The THQ of three metals was <1, which referred to safe consumption. Metal residues were heavily concentrated in artisanal cheese and yogurt after coagulation and fermentation compared with other dairy products. Accordingly, the maximum average and reduction values of Pb, Cd, and Al were 745.87, 51.99, and 71.58 μg/l and -72.87%, -56.5%, and -40.96% in Damietta cheese; 535.51, 40.11, and 62.43 μg/l and -24.11%, -20.74%, and -22.94%) in Kareish cheese; and 418.42, 31.26, and 50.66 μg/l and 3.02%, 5.90%, and 0.27% in yogurt, respectively.

CONCLUSIONS

The results indicated that consumption of raw bovine milk did not pose a risk to Alexandria citizens. Metal concentration increased in artisanal cheese and yogurt because of metal bio-gathering after coagulation and fermentation. Fat separation, churning, and boiling milk might keep metal concentration in dairy products and byproducts at lower levels than milk. Thus, they are suggested to be applied especially in highly contaminated areas.

Heavy Metals in Raw Milk and Dietary Exposure Assessment in the Vicinity of Leather-Processing Plants

The objective of this study was to assess the contamination levels of arsenic (As), lead (Pb), chromium (Cr), and cadmium (Cd) in raw milk and the subsequent potential health risk to local consumers close to leather-processing plants in China. The As and Pb concentrations in milk from contaminated areas were 0.43 ± 0.21 and 2.86 ± 0.96 μg/L, respectively, which were significantly higher than in milk from unpolluted farm, with values of 0.20 ± 0.05 and 2.32 ± 0.78 μg/L, respectively. The Cr and Cd levels in milk from contaminated areas were 1.21 ± 1.57 and 0.15 ± 0.04 μg/L, respectively, which were slightly higher than in milk from unpolluted farm, with values of 0.87 ± 0.61 and 0.13 ± 0.04 μg/L, respectively, (P > 0.05). Target hazard quotient (THQ) and hazard index (HI) values for As, Pb, Cr, and Cd from milk consumption were calculated for individuals aged 3 to 69. The THQ followed a descending order of As > Pb > Cr > Cd, with values of 0.0066-0.0441, 0.0033-0.0220, 0.0019-0.0124, and 0.0007-0.0046, respectively. The HI values (0.0124-0.0832) were far below the threshold of 1.

Determination of Toxic Elements and Arsenic Species in Salted Foods and Sea Salt by ICP-MS and HPLC-ICP-MS

Toxic elements (Cd, Pb, and As) accumulate into the environment by industrialization and natural phenomena and then pass to organisms. Analysis of toxic elements in food must be accurately carried out on a regular basis so as to avoid any adverse impact. Salted foods are difficult samples and accurate analysis of As is not easy due to salt interference. In this study, analysis of As was carried without influence of salts in three types of salted foods via an analytical method, which was validated using spiking recovery experiments and by analyzing certified reference materials. As a result, toxic elements were detected in all samples but none of these exceeded the World Health Organization recommended limits. Among the As species, arsenobetaine (AsB) was the most abundant, while inorganic As was below the detection limit in all samples. All the analyzed salted food samples appeared to be safe for consumption. In addition, the analysis of sea shrimp, freshwater shrimp, and seawater verified As bioaccumulation in these organisms from the environment.

Development, Validation and Application of an ICP-SFMS Method for the Determination of Metals in Protein Powder Samples, Sourced in Ireland, with Risk Assessment for Irish Consumers

A method has been developed, optimised and validated to analyse protein powder supplements on an inductively coupled plasma-sector field mass spectrometer (ICP-SFMS), with reference to ICH Guideline Q2 Validation of Analytical Procedures: Text and Methodology. This method was used in the assessment of twenty-one (n = 21) elements (Al, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Pb, Pt, Sn, Ti, Tl, V) to evaluate the safety of thirty-six (n = 36) protein powder samples that were commercially available in the Irish marketplace in 2016/2017. Using the determined concentrations of elements in samples (µg·kg-1), a human health risk assessment was carried out to evaluate the potential carcinogenic and other risks to consumers of these products. While the concentrations of potentially toxic elements were found to be at acceptable levels, the results suggest that excessive and prolonged use of some of these products may place consumers at a slightly elevated risk for developing cancer or other negative health impacts throughout their lifetimes. Thus, the excessive use of these products is to be cautioned, and consumers are encouraged to follow manufacturer serving recommendations.

Discrimination of goat, buffalo, and yak milk from different livestock, regions, and lactation using microelement contents

This study aims at investigating whether the livestock, lactation stage, or geographical origin of specialty milk in China could be classified by the elemental contents. Samples of goat, buffalo, and yak milk were collected from main production provinces in China and the contents of nine elements in milk from different livestock, regions, and lactation stages were determined. Statistical analysis indicated that the contents of Mn, Cu, As, Se, Cs, and Mo in mature milk were significantly different between the three livestock (p < 0.05). The trends of Mn and Cs contents of the goat milk and buffalo milk increased first and then decreased gradually during lactation. The contents of Se, Cs, Ba, and Mo in mature milk of three livestock were significantly different between the three regions (p < 0.05). The result of linear discriminant analysis (LDA) and partial least squares discrimination analysis (PLS-DA) showed that the total correct classification rates in different livestock for mature milk reached 86.7 and 90%. For goat milk, the total correct classification rates of different lactations and regions reached 88.9 and 77.8% for LDA (100 and 87.5% for PLS-DA), and followed by yak milk of different regions which achieved 88.9% for LDA (88.9% for PLS-DA). In summary, the microelements in milk showed a significant correlation with livestock, region, and lactation of goat, buffalo, and yak milk. The elemental fingerprints combined with the LDA could be potential for classifying the livestock, lactation stage, and geographical origin of milk. PRACTICAL APPLICATION: According to study the contents of miroelements in milk from different livestock, regions, and lactation stages, provide evidence and support for classifying the livestock, lactation stage, and geographical origin of milk.

Rare earth elements in drill cutting samples from off-shore oil and gas exploration activities in ultradeep waters

Rare earth elements (REEs) are essential in high technology industries and have great economic value. The monitoring of REEs concentrations in rocks from oil well drill cuttings is critical to avoid environmental contamination and evaluate new sources of these elements. However, information is scarce about the REEs concentrations in drill cuttings. In this work, the concentration of REEs in drill cuttings from oil and gas exploration wells in ultradeep coastal water of Brazilian were investigated at different depths. The drill cutting samples were submitted to microwave-assisted acid digestion prior to the determination of concentration by ICP-MS, using Rh as internal standard for calibration. The limits of quantification (LoQ) ranged from 3.3 μg kg^-1 for Ho to 198 μg kg^-1 for Sm. The accuracy was evaluated by analyzing certified reference materials for rocks. The obtained REEs concentrations agreed with the certified values, reaching 83%-105% agreement. The drill cutting depth profile analysis indicates Ce, La, Nd, Sm, and Eu concentrations up to mg kg^-1. The REEs concentrations obtained in drill cutting depth profile was analyzed by principal component analysis (PCA), and hierarchical cluster analysis (HCA) identified tendency and similarity between drill cutting samples. Three groups were formed according to the composition of the REEs. In addition, the concentration of these chemicals elements varied at different depths. The analysis of drill cuttings revealed REEs concentrations up to the mg per kg-range (ppm), potentially making this disposable material an alternative source for REEs extraction, and adding value to this material.

Toxicological analyses: analytical method validation for prevention or diagnosis

The need for reliable results in Toxicological Analysis is recognized and required worldwide. The analytical validation ensures that a method will provide trustworthy information about a particular sample when applied in accordance with a predefined protocol, being able to determine a specific analyte at a distinct concentration range for a well-defined purpose. The driving force for developing method validation for bioanalytical projects comes from the regulatory agencies. Thus, the approach of this work is to present theoretical and practical aspects of method validation based on the analysis objective, whether for prevention or diagnosis. Although various legislative bodies accept differing interpretations of requirements for validation, the process for applying validation criteria should be adaptable for each scientific intent or analytical purpose.

Mercury Biodecontamination from Milk by using L. acidophilus ATCC 4356

Food and water contaminations with heavy metals have been increasing due to the environmental pollution. Decontamination of mercury as one of the most toxic heavy metals seems necessary. The aim of this study is to use L. acidophilus ATCC 4356 to reduce the mercury amount in milk. All possible process variables (including contact time, bacterial count, mercury concentration, temperature, contact time and shaking rate) were screening by Plackett Burman design for determination of main effects. Then main effects (contact time, as well as Hg and biomass concentration) were studied in 5 levels with response surface methodology to reach maximal bioremoval efficiency. The highest decontamination efficiency (72%) was achieved in the presence of 80 μg/L of initial Hg concentration, 1 × 1012 CFU of L. acidophilus ATCC 4356 in the 4th day. Finally, the capacity of this bacterium for Mercury bioremoval was determined at different Hg initial concentrations by using the isotherm models of Langmuir and Freundlich. The results showed the higher correlation coefficient in Langmuir model so, Mercury absorptions obey Langmuir isotherm model. This study indicated that in the case of milk contamination to Hg, as reported in some countries, one of the solutions for metal decontamination could be the bioremoval by lactobacillus as natural valuable biosorbents as an environmental friendly technology.

Elemental composition of pork meat from conventional and animal welfare farms by inductively coupled plasma-optical emission spectrometry (ICP-OES) and ICP-mass spectrometry (ICP-MS) and their authentication via multivariate chemometric analysis

The demand of consumers from around the world for natural, nutritional and palatable pork meat is increasing with time. This study analyzed macro (Ca, K, Mg, Na, P), micro (Fe, Zn, Cr, Mn, Ni, Cu, Se, Sr, Cs), trace (Li, Be, V, Co, Ga, Ba, U), and toxic trace (As, Cd, TI, and Pb) elements of pork meat from conventional and animal welfare farms in South Korea. Among the elements analyzed by inductively coupled plasma-optical emission, and mass spectrometric (ICP-OES, ICP-MS) techniques, K, Fe, Mn, and Ni content were higher in animal welfare pork meat. The trace and toxic trace elements content were lower than the standard values. The principal component and linear discriminant analyses (PCA, LDA) explained the highest variance (99.82%, 99.00%) of the group based on toxic elements. These findings can thus be used to evaluate animal welfare and conventional farms pork meat quality in South Korea as well as worldwide.

Lead and cadmium biosorption from milk by Lactobacillus acidophilus ATCC 4356

The food and water contamination with heavy metals is increasing due to the environmental pollutions. Lead and cadmium are the toxic heavy metals for humans that can be found in air, soil, water, and even food. Lactic acid bacteria have the ability to remove and diminish the level of heavy metals. In this study, Lactobacillus acidophilus was used to remove lead and cadmium in milk and the capability of this valuable bacterium in biosorption of these metals low concentrations (µg/L or ppb) in milk was evaluated. First, the variables on lead and cadmium removal by this bacterium have been studied by Plackett-Burman design. Then, the bioremoval process was optimized and the three main factors, the bacterium concentration, contact time, and the initial heavy metal concentration were chosen by using a central composite design. The optimum lead and cadmium bioremoval yield of 80% and 75% were observed, respectively, at 1 × 1012 CFU of L. acidophilus in milk at the 4th day and the initial ion concentration of 100 µg/L. The 3D plots analysis showed the interaction effects on metal biosorption. This study showed that L. acidophilus is a natural effective biosorbent for lead and cadmium removal from milk.

The Biosorption Capacity of Saccharomyces Cerevisiae for Cadmium in Milk

This study aimed to evaluate the capacity of Saccharomyces cerevisiae for Cadmium absorption in milk. Nowadays, one of the most serious problems of the industrialized world is heavy metal pollution. Applying microorganisms as novel biotechnology is very useful, especially in foodstuffs. Among the biosorbents used for heavy metal removal, Saccharomyces cerevisiae has received increasing attention due to its popularity in the food industry. In this regard, the effects of some important factors such as the initial metal concentration, biomass concentration and contact time on the biosorption capacity of Saccharomyces cerevisiae were studied. The biosorption was analyzed by the inductively coupled plasma mass spectrometer (ICP-MS). The maximum cadmium (Cd) removal (70%) was at 80 μg/L of Cd concentration in milk samples containing 30 × 108 CFU Saccharomyces cerevisiae at the end of storage time (the 4th day). There were no significant differences in the sensory and physicochemical properties (pH, acidity and density) of milk samples during storage (p < 0.05). The isotherm studies were followed by two popular models, Langmuir and Freundlich, and the results showed a better fit to the Langmuir isotherm. Altogether, the results of this study demonstrate that the approach of using this valuable yeast could be applied for food detoxification and producing healthier foodstuffs.