Concentrations and bioavailability of cadmium (Cd) and lead (Pb) were determined in cocoa powders and related products (beans, liquor, butter) of different geographical origins. Particular attention was paid to the fractionation of these metals, which was investigated by determining the metal fraction soluble in extractant solutions acting selectively with regard to the different classes of ligands. The targeted classes of Cd and Pb species included: water-soluble compounds, polypeptide and polysaccharide complexes, and compounds soluble in simulated gastrointestinal conditions. The bioavailability of Cd and Pb from cocoa powder, liquor and butter was evaluated using a sequential enzymolysis approach. The data obtained as a function of the geographical origin of the samples indicated strong differences not only in terms of the total Cd and Pb concentrations, but also with regard to the bioavailability of these metals. The Cd concentrations in the cocoa powders varied from 94 to 1833 microg kg(-1), of which 10-50% was potentially bioavailable. The bioavailability of Pb was generally below 10% and the concentrations measured in the cocoa powders were in the 11-769 microg kg(-1) range. Virtually all the Cd and most of Pb were found in the cocoa powder after the pressing of the liquor.

Closed microwave digestion and a high-pressure asher have been evaluated for wet-oxidation and extraction of lead, cadmium, chromium, and mercury from a range of typical packaging materials used for food products. For the high-pressure asher a combination of nitric and sulfuric acids was efficient for destruction of a range of packaging materials; for polystyrene, however, nitric acid alone was more efficient. For microwave digestion, a reagent containing nitric acid, sulfuric acid, and hydrogen peroxide was used for all materials except polystyrene. Use of the high-pressure asher resulted in the highest recoveries of spiked lead (median 92%), cadmium (median 92%), chromium (median 97%), and mercury (median 83%). All samples were spiked before digestion with 40 microg L(-1) Cd, Cr, and Pb and 8 microg L(-1) Hg in solution. The use of indium as internal standard improved the accuracy of results from both ICP-MS and ICP-AES. Average recovery of the four elements from spiked packaging materials was 92 +/- 14% by ICP-MS and 87 +/- 15% (except for mercury) by ICP-AES. For mercury analysis by CVAAS, use of tin(II) chloride as reducing agent resulted in considerably better accuracy than use of sodium borohydride reagent.

An ED-XRF method for the rapid determination of a series of analytes (phosphorus, sulfur, chlorine, potassium, calcium, iron, zinc) in milk-based products has been developed and validated. The investigated samples were commercial products obtained from various parts of the world. Reference values measured by inductively-coupled plasma-optical emission spectroscopy and by potentiometry for chloride were used to calibrate the ED-XRF. Calibrations were established with 30 samples, and validation was made using a second set of 30 samples. An evaluation of this alternative method was done by comparison with data from the reference methods. Pellets of 4 g were prepared under 2 tons of pressure. For each sample, 3 pellets were prepared and analyzed. Limits of quantification and repeatabilities were evaluated for the described analytes.

Ginseng extracts are available as ingredients for improving energy and vitality and can be used in functional foods and as flavouring ingredients. A survey was been performed to determine the content of pesticides and toxic metals in ginseng extracts. Forty-seven samples from 20 suppliers, including both Panax ginseng C. A. Meyer (Asian ginseng) and P. quinquefolius (American ginseng) species, were analysed for arsenic content and for the following metals: aluminium, molybdenum, chromium, copper, magnesium, zinc, cadmium, mercury and lead, while pesticide residues were analysed in 30 samples from 17 suppliers. The results showed that 24 samples (80%) contained pesticides above the detection limit and 13 samples (43%) did not comply with the maximum residue limits (MRL) for total quintozene, hexachlorobenzene, total hexachlorocyclohexane, lindane, total heptachlor, e-chlorpyrifos and folpet, imposed for botanical extracts. Total quintozene, hexachlorobenzene, total hexachlorocyclohexane and lindane were present in all contaminated samples and exceeded the MRL in eleven samples, with levels up to 55 and 30 times their respective MRL. Cadmium (<0.05-259 microg kg(-1)), mercury (<0.3-72 microg kg(-1)), lead (3-2710 microg kg(-1)) and arsenic (<0.3-918 microg kg(-1)) were present in most samples at concentrations lower than the MRL imposed for flavouring substances. Among the other elements, aluminium (0.3-1068 mg kg(-1)) was the most abundant.

An adequate mineral supply to preterm infants is essential for normal growth and development. This study aimed to compare the mineral contents of human milk (HM) from healthy mothers of preterm (28–32 weeks) and full term (>37 weeks) infants. Samples were collected weekly for eight weeks for the term group (n = 34) and, biweekly up to 16 weeks for the preterm group (n = 27). Iron, zinc, selenium, copper, iodine, calcium, magnesium, phosphorus, potassium, and sodium were quantitatively analyzed by Inductively Coupled Plasma-Mass Spectrometry. The mineral contents of both HM showed parallel compositional changes over the period of lactation, with occasional significant differences when compared at the same postpartum age. However, when the comparisons were performed at an equivalent postmenstrual age, preterm HM contained less zinc and copper from week 39 to 48 (p < 0.002) and less selenium from week 39 to 44 (p < 0.002) than term HM. This translates into ranges of differences (min–max) of 53% to 78%, 30% to 72%, and 11% to 33% lower for zinc, copper, and selenium, respectively. These data provide comprehensive information on the temporal changes of ten minerals in preterm HM and may help to increase the accuracy of the mineral fortification of milk for preterm consumption.

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Microplastics (MPs) have gained a high degree of public interest since they are associated with the global release of plastics into the environment. Various studies have confirmed the presence of MPs throughout the food chain. However, information on the ingestion of MPs via the consumption of many commonly consumed foods like dairy products are scarce due to the lack of studies investigating the “contamination” of this food group by MPs. This lack of occurrence data is mainly due to the absence of robust analytical methods capable of reliably quantifying MPs with size < 20 µm in foods. In this work, a new methodology was developed to accurately determine and characterize MPs in milk-based products using micro-Raman (μRaman) technology, entailing combined enzymatic and chemical digestion steps. This is the first time that the presence of relatively low amounts of small-sized MP (≥ 5 µm) have been reported in raw milk collected at farm just after the milking machine and in some processed commercial liquid and powdered cow’s milk products.

A simple and fast method for the determination of a series of analytes (sodium, magnesium, phosphorus, sulfur, chlorine, potassium, calcium, iron, zinc) in milk‐based products by wavelength‐dispersive x‐ray fluorescence spectrometry was developed and validated. Reference values were obtained by inductively coupled plasma optical emission spectroscopy and by potentiometry for chloride. The investigated samples were commercial products obtained from various parts of the world. Pellets of 4 g were prepared under 2 t pressure. For each sample, three pellets were prepared and analysed. Limits of quantification and repeatabilities were evaluated for the described analytes. Calibrations were established with 29 samples and validation of the method was made using a second set of 29 samples. An evaluation of this alternative method was done by comparison with data from the reference methods, using robust statistics. Copyright © 2004 John Wiley & Sons, Ltd.