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Milk proteins, integral to stable foam production, exhibit seasonal and type-dependent variations. Understanding the impact of protein levels with and without fat on foaming properties is essential for selecting suitable milk types and controlling the foaming process. In this study, we employed steam injection and mechanical mixing to assess foamability, foam stability, and foam structure of (1) reconstituted skim milk powder dispersions (1.5–15% solids concentration, corresponding to 0.5–5.0% protein), (2) reconstituted whole milk powder and commercial whole milk dispersions (0.5% protein), and (3) whole milk with added skim milk powder and milk protein concentrate (3.5 and 4% protein) and butter milk powder (0.5 and 1% total solid content). Results reveal that increasing solids concentration from 1.5 to 15% significantly increased lactose content, viscosity, and surface tension. However, these changes did not impact foamability or foam stability, while slightly decreasing air bubble size. At 0.5% protein, skim milk powder dispersions demonstrated higher foam volume (16 times greater) and more stable foam compared to reconstituted whole milk powder and whole milk dispersions, despite similar foam structure and appearance. These findings emphasize the substantial influence of the protein/fat ratio on milk's foaming properties. Additionally, the addition of skim milk powder, milk protein concentrate, or butter milk powder at the investigated content did not affect the foaming properties of whole milk. [ABSTRACT FROM AUTHOR]

The present work illustrates the potential application of laser-induced breakdown spectroscopy (LIBS) for quick in situ authentication and evaluation of the minerals in milk powder. LIBS spectra of milk powders confirm the presence of the spectral lines of organic elements like Carbon (C), Hydrogen (H), Nitrogen (N), and inorganic elements/minerals like Calcium (Ca), Potassium (K), Magnesium (Mg), and Sodium (Na), along with the electronic bands of the CN molecule using National Institute of Standards and Technology (NIST) database. With the help of integrated intensity of the spectral lines of the various elements present in the LIBS spectra of the samples, we have compared the concentrations of minerals in different brands of milk samples. Rapid differentiation/discrimination/classification of various milk samples based on major and minor elements present in milk powder was performed using a Chemometric technique such as Principal component analysis (PCA). We have applied partial least square regression (PLSR) of the different vibronic bands of the CN molecule to estimate the concentration of protein level in milk samples. Further, the presence of the organic molecules/compounds in milk samples was confirmed by their functional group present in the Fourier-transform infrared (FTIR) spectra and by the absorption peaks/bands present in UV–visible spectra of the milk samples. Biochemical analysis was used to estimate and compare the protein level in the milk samples. The results of the present work reveal the potential of LIBS for quick, real time, cost effective, easy-to-operate, and high sampling rates analysis of any edible products. [ABSTRACT FROM AUTHOR]

Spore-forming bacteria are common contaminants of milk powder and processing lines and a major concern for the dairy industry. This dairy-associated microflora was studied extensively and well characterized in developed countries (exporters of milk powder), compared to developing countries (importers). Thereby, the quality issues affecting dairy powders and derived products are not fully controlled in developing countries. That is the case in Algeria, where recombined or reconstituted pasteurized milk is of low quality, reduced shelf-life, and the related dairies faced recurrent contaminations due to spores and biofilms. The transfer of spore-forming bacteria from exporters of dairy powders to importers in developing countries is an interesting topic, not thoroughly investigated. In addition, milk powder-based products are growing worldwide and their attributes, processes and technologies need to be better understood and controlled. This review analyzes issues affecting milk powder quality, based on few studies from developing countries in comparison with current knowledge, and emphasis on the case in Algeria. It provides information on how spore-forming bacteria and their biofilms affect the quality and shelf-life of recombined pasteurized milk produced in Algeria and compromise hygiene conditions in local dairy plants. Challenges and perspectives for better management of spore transfer from exporters of dairy powders to importers in developing countries are thereby outlined. Highlights: The presence of spore-forming bacteria in milk powder is a serious safety issue. Spores are not well known, characterized and controlled in importers from developing countries. Spores cause recurrent contamination of pasteurized milk and biofilm issues in Algerian dairies. Challenges are how to reduce the flow of spores in milk powder trade. Perspectives on identification targeting predominant spores and improvement of biofilm removal. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the concentration and health risk of trace elements in milk powder and baby food samples marketed in Iran using inductive couple plasma/optical emission spectroscopy (ICP-OES) method. The limit of detection (LOD) and limit of quantification (LOQ) were ranged from 1.80 × 10–5 to 2.17 × 10–3 and 6.00 × 10–5 to 7.22 × 10–3 mg/kg, respectively, with recoveries ranged from 92 to 105%. Zinc (Zn) was found in a high mean concentration (8.49 × 10–1 ± 3.93 × 10–2 mg/kg) in milk powder, and iron (Fe) was found in the highest mean concentration (2.04 ± 3.61 × 10–2 mg/kg) in baby food. The Monte Carlo simulation results for the infants revealed that the rank order of the hazard quotient (HQ) index was mercury (Hg) > nickel (Ni) > arsenic (As) > cadmium (Cd) > aluminum (Al). Further, the result of non-carcinogenic and probability of carcinogenic risk was lower than the limits of safe risk (HQ > 1 and cancer risk (CR) > 1 × 10–4). In conclusion, the toxic elements content in the tested products was sufficiently low, and all of the milk powder and baby food sold in Iran could be considered safe for infants and children. [ABSTRACT FROM AUTHOR]

Creatine is a well-known member of supplement family and is widely preferred by consumers for therapeutic applications, muscle strength, and energy recovery. This study describes a new concept, which is based on a simple, one-step, and non-enzymatic creatine detection system on the Pt electrode. The creatine content of food supplements was determined using an elemental analyzer, and five different supplements were separated in terms of creatine. Three supplements were investigated as creatine sources, and the other two supplements were considered as branched-chain amino acid sources. For the electrochemical detection of creatine, cyclic voltammetry and square-wave voltammetry techniques were used. Graphene oxide and carbon nanotube-modified surfaces were applied in addition to bare Pt surface; however, bare Pt surface was found to be superior to the modified surfaces. Creatine was successfully detected using the proposed Pt electrode, and the limit of detection was calculated to be 36.0 µg L−1. The obtained selectivity allowed performing a voltammetric comparison of creatine and branched-chain amino acid supplements. Real sample analysis was performed by analyzing milk powder; however, milk powder supplied only 32.4% of creatine content. This study presents a new method for detection of food supplements without the need for modification, high-cost, or pretreatment process. [ABSTRACT FROM AUTHOR]

The development of products with buffalo milk has increased due to its peculiar characteristics, such as taste and high content of total solids, which has attracted consumers and the food industry.In this context, the objective was to develop and evaluate the microstructural properties of chocolates with different concentrations of buffalo milk powder (0%, 5%, 10%, 15% and 20%) through polymorphism, microscopy and rheological studies. For the polymorphism, the X-ray diffraction technique (XRD) was performed, while the crystal morphology was observed by scanning electron microscopy (SEM). The addition of levels of more than 10% buffalo milk caused notable changes in XRD diffractograms, demonstrating the appearance of different polymorphic forms. Microscopy analysis revealed changes in the structure of the matrix with an increase in the concentration of buffalo milk, presenting more continuous surfaces, associated with milk proteins, which have emulsifying capacity. The Herschel-Bulkley model adequately described the flow behavior of the formulations. There was an increase in all rheological properties (yield stress, viscosity, thixotropy and loss tangent (tang δ)) in chocolates with higher concentrations of milk. For that, the composition of the milk influences the degree of structuring of the chocolate. Considering this technological information, it is important to highlight that the production of buffalo milk chocolates shows potential for technological innovation. [ABSTRACT FROM AUTHOR]

Folic acid (FA) is a vitamin essential for human physiology; thus, rapid, accurate, and sensitive methods for its detection and quantification in different biological samples are necessary. A fluorescent ratiometric nanoprobe (the complex composed of quantum dots and carbon dots) based on carboxyl-modified quantum dots (QDs) and amino-modified graphene-based carbon dots (CDs) has been developed for the visual determination of folic acid (FA). The nanoprobe is the composition in which QDs were covalently bonded with CDs. Red and blue fluorescence of nanoprobe can be selectively quenched and enhanced by FA, respectively. Thus, the nanoprobe is capable to generate clearly visible fluorescence color change from pink to blue upon exposure to UV light. Depending on the color change and its intensity, FA can be identified, and their concentrations can be determined. The sensor prepared based on the nanoprobe demonstrated good selectivity and sensitivity toward FA with exceptionally low detection limit equal to 0.039 μM. We also prepared a paper-based sensor to demonstrate convenient and simple approach to visually detect FA. Thus, the nanoprobe demonstrated feasibility of rapid real-time quantitative FA detection; considering its simple, effective, and practicality, expectedly it can be used for practical application. [ABSTRACT FROM AUTHOR]

The objective of this study was to establish and validate an UHPLC-MS/MS method for simultaneous determination of advanced glycation endproducts (AGEs) in either free or bound form in milk powder. The target analytes in free form in milk powder were extracted by 1% trichloroacetic acid, while target analytes in bound form were hydrolyzed by hydrochloric acid to cleave the protein amide bond and consequently dissociated. After extraction and purification, Nε-(carboxymethyl)lysine (CML) and Nε-(1-carboxyethyl)lysine (CEL) were quantified by internal standard method and pyrraline (Pyr) was by external standard method. Results revealed that three target analytes displayed excellent linearity in their corresponding concentration ranges. Limits of quantifications (LOQs) were in the range of 20–95 μg/kg. The average recoveries of three target analytes spiked at three concentration levels were in the ranges of 81.8–107.2% with relative standard deviations (RSDs) of 3.5–8.1%. Finally, the described method was proved to be suitable for the quantification of these AGEs in milk powder products. [ABSTRACT FROM AUTHOR]

A graphitic carbon nitride (g-C3N4/Fe3O4)–based magnetic solid-phase extraction (MSPE) approach was established for fast and simple analysis of estrogens in milk powders. The composites were characterized by X-ray diffractometer, scanning electron microscope, and Brunauer-Emmett-Teller surface area and pore size distribution analyzer. Compared with the bulk g-C3N4, g-C3N4/Fe3O4 gave a narrower distribution of mesopores and provided an enhanced surface area from 77.1 to 113.7 m2/g. Polar analytes of estrogens were selected as model compounds and the extraction of four estrogens was achieved in n-hexane using 15 mg of adsorbent within only 2 min. Possible extraction mechanism of g-C3N4/Fe3O4 for these estrogens was explored in terms of the polarity of the analytes and the adsorption performance of the adsorbent. The hydrophobicity and the hydrogen-bond interaction between the estrogens and g-C3N4 were responsible for the efficient adsorption. Combined with HPLC, MSPE with the prepared adsorbent gave the enhancement factors of 20 to 24 and the linear ranges of 2–200 μg/kg for 17β-estradiol and 17α-ethinylestradiol, 1.5–150 μg/kg for estrone, and 3–300 μg/kg for hexestrol. The detection limits and quantification limits for the estrogens in milk powders were 0.5–0.9 μg/kg and 1.5–3.0 μg/kg, respectively. The recoveries varied from 75.1 to 97.2%, with the intra-day and inter-day precisions ≤ 14.2%. Furthermore, the enrichment of the analytes and the clean-up of fat and protein interferences were achieved simultaneously with one-step g-C3N4-based MSPE. The present method was convenient, fast, and sensitive, and therefore could be successfully applied for the determination of estrogens in milk powders. [ABSTRACT FROM AUTHOR]

Melamine adulteration is a fraudulent practice to increase the protein content of food in some areas of the world. In 2008, many babies in China suffered from serious illness and death because of melamine-tainted powdered infant formula. The issue prompted researchers to develop methods on detecting melamine in milk powder. Optical spectroscopy technologies have been proven to be effective in identifying and quantifying food contaminants. To provide useful information for future researches, the widely used optical spectroscopy technologies, such as near-infrared, middle-infrared, Raman, fluorescence, terahertz, hyperspectral imaging technology, etc., were introduced briefly. Then the applications of these optical spectroscopy technologies in determining melamine-adulterated milk powder in the last decade were reviewed. Meanwhile, the potential advantages and limitations of these technologies were put forward, and some suggestions for future researches in detecting melamine-adulterated milk powder were given. [ABSTRACT FROM AUTHOR]

In the present study, the deep eutectic solvent-based extraction method has been developed for separation of Zn prior to ICP-OES analysis. Five different choline chloride-based deep eutectic solvents were prepared. The Zn extraction ability of DESs from milk powder and baby formulation samples which contain a high amount of milk protein was investigated. The parameters affecting the extraction efficiency such as the amount and type of solvent, extraction time and ambient temperature were optimized. Oxalic acid-based DES gave the highest yield and reproducible results and appropriate preparation criteria. It is concluded from the results that DES-oxalic can quantitatively extract Zn from milky samples. The analytical parameters such as linear calibration range, limit of detection (4.2 µg L−1) and quantification (14.1 µg L−1) were also calculated. The added-found method is successfully applied to ERM BD 150 standard reference material, and the recovery values and standard deviation values were found between the ranges of 79.4–97.21 µg L−1 and 4.1–6.31 µg L−1, respectively. The method was also applied to real samples, and the recovery values were found between 73 and 106% in the spiked samples. [ABSTRACT FROM AUTHOR]

The quality of milk powder is largely determined during it manufacture process by the morphological characteristics of powder particles. Considering that, the main research objective of this study was to determine whether parameters of the production process contribute to differences in the microstructure of the manufactured powders, and by this means affect their functional traits. To diversify the milk powder production process, various temperatures of the inlet air were used during drying, i.e. 140, 150 and 160 °C. An image fractal analysis was employed and powder particle sizes were compared with respective results achieved in the instrumental analysis using the laser diffraction method. Values of fractal dimensions decreased slightly along with drying temperature increase, what demonstrates that the technological parameters are reflected in the microstructure of milk powders produced. Although particle sizes determined with both methods fitted within the same range of values, the contribution of particular fractions slightly differed and the choice of the appropriate approach may not always be unambiguous. Finally, the fractal dimension is a precise parameter which provides the accurate and explicit characteristics of milk powder microstructure and as such should be recommended for the characterization of irregular structures of different food products. [ABSTRACT FROM AUTHOR]

The authors have synthesized a phosphorescent probe of type SiO2-QD-MIP, where QD stands for Mn:ZnS quantum dots and MIP is a polymer coating that was molecularly imprinted with cephalexin. The nanoprobe with high specificity was prepared via sol-gel polymerization using thioglycolic acid (TGA)-modified QDs as luminescent materials, cephalexin as the template, 3-aminopropyltriethoxysilane as the functional monomer, and tetraethoxysilane as the crosslinking agent. The SiO2-QD-MIPs were characterized by X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectrometry. The orange emission of the probe, with excitation/emission maxima at 295/590 nm, decreases linearly in the 2.5–50 μg·L−1 cephalexin concentration range with a limit of detection (LOD) of 0.81 μg·L−1. The nanoprobe was successfully applied to the determination of cephalexin in (spiked) raw milk and milk powder. The recoveries ranged from 91.7 to 103.7%. [ABSTRACT FROM AUTHOR]

Triacylglycerols (TAGs) are considered the main component of milk fat; possess significant functional roles from the technological, nutritional and physiological points of view. In this study, an ultra-performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry was applied to identify the molecular species composition of TAGs in buffalo, camel, and ewe milk powders. The separation of TAGs was achieved by using two mobile phases; acetonitrile/isopropanol (1:9, v/v) as mobile phase A, and 40% acetonitrile as mobile phase B, the binary gradient elution allowed the separation of milk TAGs in consistent with the increase in partition number. More than 180 TAGs in buffalo milk, 90 TAGs in camel milk, and 129 TAGs in ewe milk were unambiguously identified, and the most abundant molecular species in the three types of milk powders were detected at mass to charge (m/z) values of 682.53, 822.67, and 656.53, respectively. The total acyl carbon numbers of buffalo milk TAGs ranged between 26 and 54, with double bonds from 0 to 6. While, the total acyl carbon numbers of camel milk TAGs ranged between 42 and 54, with double bonds from 0 to 3. The total acyl carbon numbers of ewe milk TAGs ranged between 26 and 52, with double bonds from 0 to 2. The major fatty acids (FAs) in the different types of milk powders were myristic, palmitic, stearic, oleic, and linoleic. The positional distribution of saturated FAs at the sn-2 position was higher in buffalo milk powder as compared to camel and ewe milk powders. This study reports a comprehensive identification of TAGs molecular species in different types of milk powders. [ABSTRACT FROM AUTHOR]

Polypeptide antibiotics abuse can lead to antibiotic residues in food products and have unwanted effects on human health. A selective, accurate, and sensitive analytical method for the simultaneous determination of four polypeptide antibiotics (gramicidin S, bacitracin, polymyxin B, and polymyxin E) in infant formula powder was developed using solid-phase extraction (SPE) combined with high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). The samples were extracted with acidified methanol, deproteinized with acetonitrile, and degreased with n-hexane before SPE. After cleanup with 0.1% formic acid and methanol (3:1, v/v) in Oasis HLB cartridges, the extracts were analyzed by HPLC–MS/MS with electrospray ionization (ESI) source and time-scheduled multiple reaction monitoring (MRM). Linearity was assessed by using matrix-matched standard calibration and good determination coefficients (r2 > 0.995) were obtained. The average recoveries for blank sample at three spiked concentration levels were in the range of 82.8–101.2%. The limits of detection (LODs) and limits of quantitation (LOQs) of all analytes were in the range of 5–15 μg kg−1 and 20–50 μg kg−1, respectively. The intra-day and inter-day precisions were lower than 10%. The results of method validation demonstrated that the developed method is accurate and reliable, and it can be applied for screening and quantitation of target polypeptide antibiotics in food. [ABSTRACT FROM AUTHOR]

In order to improve the competitiveness of Philippine food products in the global market, the Department of Science and Technology—Food and Nutrition Research Institute initiated proficiency testing (PT) programs on some nutrition labeling components using food matrices commonly exported by the country. The institute realized the need to organize affordable, accessible and reliable PTs designed to address the needs of the local testing laboratories. FNRI organized several PT rounds on different food matrices for the analyses of proximates, minerals, total dietary fiber, saturated fatty acids, cholesterol and vitamin C. More than 20 laboratories (government and private) participated in these PT programs, which helped them obtain/sustain their accreditation to ISO/IEC 17025:2005. In February 2013, the Proficiency Testing Laboratory (PTL) was accredited to ISO/IEC 17043:2010 by the Thailand Bureau of Laboratory Accreditation. This strengthened its credibility by being recognized as the first accredited PT provider in the Philippines. Initially, the scope of the accredited PTs included the analysis of proximates and minerals in infant formula. It was extended to include five different food matrices (infant formula, milk powder, wheat flour, corn-based snack food and powdered concentrate-water-based flavored drinks) for nutrition labeling parameters. The PTL continuously organizes new PT rounds to expand its scope of accreditation. [ABSTRACT FROM AUTHOR]

A method based on the ultra-high-performance liquid chromatography tandem mass spectrometry for determination of the residues of sex hormones, glucocorticoids, and sedatives in milk powder was developed. The sample was extracted with the acetic acid-acetonitrile (1:99, v/v) twice, purified by the PRiME hydrophilic-lipophilic balance (HLB) cartridges and analyzed by the ultra-high-performance liquid chromatography-tandem mass spectrometry. The analytes were separated by the Waters Acquity UPLC™ BEH C18 column (50 mm × 2.1 mm, 1.7 μm) and determined using the electrospray ionization in the positive mode with the multiple reaction monitoring (MRM). The developed method was validated with the specificity, linearity and range, matrix effects, recovery, and precision. The results showed that the analytes were linear with the correlation of determinations (R2) higher than 0.991 in the corresponding ranges. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.1-1.1 μg kg−1 and 0.3-3.8 μg kg−1, respectively. The average recoveries of the analytes ranged from 78.5 to 107.0% with the relative standard deviations lower than 15%. The practical applicability was tested by analyzing real samples and the progesterone was observed in two samples. [ABSTRACT FROM AUTHOR]

The scope of this study was the development, optimization and validation of an analytical method for the determination of selected heavy metals and trace elements (As, Hg, Se, Cd, Cu, Pb, Mn, Fe, Ni, Zn, Cr) in milk powder, using microwave-assisted digestion. A statistical experimental design approach using central composite design (CCD) was carried out, to investigate the effects of three independent pretreatment variables (final digestion temperature (°C), HNO3 concentration (in % w/v), microwave hold time) on the heavy metal recovery of spiked undigested milk powder sample and to calculate the variable factor values which produce the optimum recovery. CCD results revealed that the optimum digestion conditions, with respect to maximum recovery were as follows: temperature 190 °C, HNO3 56.8% w/v, and digestion time of 8.47 min. The method was fully validated. Recoveries for all metals ranged between 92 and 108% while intra-day repeatability was below 6.59% (rsd). A certified reference material (ERM BD 150) that included 8 out of the total 11 heavy metals of the present study (Hg, Se, Cd, Cu, Pb, Mn, Ni, and Zn) was used to test the accuracy of the method where acceptable recovery values ranging between 96 and 107% were obtained. High heavy metal recoveries, short digestion time, and low acid consumption were the advantages of the pretreatment method. The analytical process was successfully applied for the determination of heavy metals in different milk samples from the Greek market. Heavy metal concentrations for Ni, Cr, Pb, Cd, Se, Mn, and Cu measured in this study reached 307, 102, 8.01, 5.96, 60.2, 519, and 438 μg/kg wet weight (ww), respectively. Zn and Fe were found at concentrations ranging 3.21-8.39 and 0.170-10.1 mg/kg ww, respectively. Risk assessment based on the WHO tolerable daily intake levels and the calculated target hazard quotients revealed that the consumption of the selected milk samples is considered safe. [ABSTRACT FROM AUTHOR]

A set of measurements have been conducted to determine the levels activity of gamma-emitters present in infant formula. The study of different samples shows the presence of the following radionuclides: 226Ra, 232Th and 40K with respectively average activity of 0.52 ±  0.087, 0.51 ± 0.062, 371.98  ± 3.68 Bq/kg. The mean annual doses lead to 0.62 and 0.24 mSv/year whereas the total risk is about 7.91 × 10−6 and 5.32 × 10−6 respectively ≤ 1 year and 1–2 years old infants. The obtained results show that no significant radiation dose and no risk to the infants due to consumption of these milks. [ABSTRACT FROM AUTHOR]

The lack of updated knowledge about the physical properties of milk powders aimed us to evaluate selected physical properties (water activity, particle size, density, flowability, solubility and colour) of eleven skim and whole milk powders produced in Europe. These physical properties are crucial both for the management of milk powder during the final steps of the drying process, and for their use as food ingredients. In general, except for the values of water activity, the physical properties of skim and whole milk powders are very different. Particle sizes of the spray-dried skim milk powders, measured as volume and surface mean diameter were significantly lower than that of the whole milk powders, while the roller dried sample showed the largest particle size. For all the samples the size distribution was quite narrow, with a span value less than 2. The loose density of skim milk powders was significantly higher than whole milk powders (541.36 vs 449.75 kg/m). Flowability, measured by Hausner ratio and Carr's index indicators, ranged from passable to poor when evaluated according to pharmaceutical criteria. The insolubility index of the spray-dried skim and whole milk powders, measured as weight of the sediment (from 0.5 to 34.8 mg), allowed a good discrimination of the samples. Colour analysis underlined the relevant contribution of fat content and particle size, resulted in higher lightness ( L*) for skim milk powder than whole milk powder, which, on the other hand, showed higher yellowness ( b*) and lower greenness (− a*). In conclusion a detailed knowledge of functional properties of milk powders may allow the dairy to tailor the products to the user and help the food processor to perform a targeted choice according to the intended use. [ABSTRACT FROM AUTHOR]

Milk and honey in combination can play a vital role in fulfilling the requirement of food product having nutritional as well as functional properties. The present study was carried out to investigate various compositional, physical, functional, and flow properties (cohesion index, powder flow speed dependency test, and caking test) in buffalo, cow, and mixed milk powders with changing the concentration level of honey addition from 0 to 20%. All prepared powdered samples exhibited 3-4% moisture content, 0.40 g/cc bulk density, matching with powders available in commercial market. DPPH scavenging capacity, total phenolic and total flavonoid content were increased from 2.67 to 15.87%, 0.41 to 2.68 mg of GAE/g of powder, and 0.04-1.44 mg of RE/g of powder, respectively. Lower cohesion index (9-14) confirmed the noncohesiveness of powders. Lower Compaction coefficient and powder stability were close to 1 which verified its free flowing nature. Lower cake height ratio of powdered samples indicated that they were less susceptible to cake formation. [ABSTRACT FROM AUTHOR]

This study investigated the laboratory performance on the analyses of mandatory nutrients for nutrition labelling in Thailand and aimed to upgrade the proficiency test (PT) material into a reference material (RM). This milk powder with sufficient homogeneity and multiple nutrient compositions provided an acceptable PT material. Twenty ISO 17025 accredited laboratories participated in this study, and analytical performance was investigated using ISO 17043 and ISO 13528 standards. Satisfactory performance (| z| ≤ 2, for both within- and between-laboratory variations) was found among participating laboratories on the analyses of total fat, saturated fat, cholesterol, protein, sugar, sodium, vitamin B, vitamin B, calcium, iron, moisture, and ash. The values of these nutrients (mean and standard deviation) were applied to upgrade the PT material to be used as a reference material. For a trial, moisture, vitamin B, and vitamin B were selected as three representative nutrients to develop reference values as mean and uncertainty following ISO Guides 34 and 35 for RM production. The mean of moisture, vitamin B, and vitamin B values of 2.34 g/(100 g), 0.64 mg/(100 g), and 0.78 mg/(100 g) were obtained with the relative expanded uncertainty of 12.2 %, 12.7 %, and 9.7 %, respectively. The developed RM can be used as quality control sample or as PT material with reference nutrient values among the laboratories in Thailand. [ABSTRACT FROM AUTHOR]

The article presents the use of gas chromatography-mass spectrometry (GC-MS) technique in a method for the determination of 18 anabolic hormones from synthetic stilbenes, steroids and resorcylic acid lactones (RALs) groups in raw milk and milk powder. Sample preparation consisted of liquid-liquid extraction with diethyl ether and purification by solid phase extraction (SPE). Prior to instrumental analysis, the reaction of derivatisation with the heptafluorobutyric anhydride or N-methyl- N-trimethylsilyltrifluoroacetamide was performed. Method validation was carried out according to the required performance criteria of the Commission Decision 2002/657/EC. The apparent recovery of all analytes at 1 μg L (kg) level was ranged between 70.4 and 119.4 % with the coefficients of variation values less than 30 %. The decision limits (CCα) and the detection capabilities (CCβ) were in the range of from 0.11 to 0.44 μg L (kg) and from 0.19 to 0.75 μg L (kg), respectively. The procedure has been accredited and successfully applied as a screening method for the presence of hormone residues in the study of commercial samples of milk. [ABSTRACT FROM AUTHOR]

A method for determination of vanillin and ethyl-vanillin in milk powder by auto headspace solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was established. Vanillins in sample were extracted with SPME through a fused-silica fiber coated with divinylbenzene/polydimethylsiloxane. The analytes were desorbed by GC at 260 °C for 5 min and separated on a DB-5MS capillary column and detected by MS with EI source by selected ion monitoring mode (EI-SIM). As a result, the limit of detection of vanillin and ethyl-vanillin was 0.1 and 0.05 mg/kg. The spiked recovery was between 90.0 and 100 %, and the RSD ranged from 1.9 to 5.1 % ( n = 6). This method eliminated the interferences from complicated matrix effectively. The method was successfully applied for quick determination of vanillin and ethyl-vanillin content in milk powder samples. [ABSTRACT FROM AUTHOR]

A simple method using dispersive liquid-liquid microextraction (DLLME) combined with capillary zone electrophoresis (CZE) was developed for detection and quantification of vanillin in milk powder. CZE analytical conditions and DLLME parameters were optimized. The optimal running buffer was 10 mM borate buffer at pH 8.0. 4-Hydroxybenzaldehyde was used as the internal standard. The optimized microextraction conditions were 5.0 mL sample solution at pH 5.5, 8 % ( m/ v) NaCl added, with 120 μL CHCl (extraction solvent), and 0.8 mL tetrahydrofuran (THF) (disperser solvent) injected. Under the optimum extraction and detection conditions, vanillin was determined in 5 min, with the limit of detection at 0.02 μg mL and a quantitation range of 0.05-10 μg mL. The method was successfully applied to the analysis of vanillin in infant milk powder samples. The recoveries obtained were between 89.7 and 95.1 % with relative standard deviation (RSD) less than 2.5 %. [ABSTRACT FROM AUTHOR]

This study uses a point-scan Raman spectral imaging system for quantitative detection of melamine in milk powder. A sample depth of 2 mm and corresponding laser intensity of 200 mW were selected after evaluating the penetration of a 785 nm laser through milk powder. Horizontal and vertical spatial resolutions of 0.25 and 0.5 mm were selected for effective detection of melamine particles mixed with milk powder. The selected imaging parameters were used to quantitatively detect melamine concentration in milk powder. Ten different concentrations of melamine in milk (0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, and 1 %- w/w) were prepared by mixing each mixture of melamine and milk powder in an acoustic mixer for 15 min, and seven sub-samples of each concentration were imaged. Each sub-sample image was acquired over a 45 mm × 45 mm surface area. Background-corrected Raman spectral images were converted into binary images and an intensity threshold value of 400 was applied to convert melamine pixels into black pixels and milk pixels into white pixels (background). At least one melamine pixel was detected in every sub-sample across all ten concentration levels except for one sub-sample at the 0.005 % concentration. It was found that the method developed in this study can detect melamine particles present at concentrations as low as 0.005 %. A linear relation was established between the detected melamine concentrations and the actual concentrations of the mixtures, with correlation coefficient of 0.99. The results show that the method developed in this study can be used for non-destructive quantitative prediction of melamine in milk powder to minimum concentration level of 0.005 %. [ABSTRACT FROM AUTHOR]

In this paper, a comparative study between three acid decomposition procedures of milk powder samples for the determination of Ca, Cu, Fe, K, and Na by optical emission spectrometry with inductively coupled plasma is presented. Utilizing a reflux system, it was possible to increase the temperature of the digester block above the boiling point of the reaction medium, avoiding the loss of analyte and the excessive evaporation of the acids during the heating. Conditions of acidity (10 mL HNO/HSO), temperature (350 °C), and decomposition time (4 h) were defined by evaluation of residual carbon content. Acid digestion in an open system with a cold finger was compared with a conventional open system (4 h ate 120 °C), as well as with microwave digestion (heating ramp to 180 °C by the time 45 min), for four commercial samples of milk powder. For the three sample preparation procedures, the values of the analyte concentrations in all analyzed samples were similar. The accuracy of the acid digestion procedures for Ca, Cu, Fe, K, and Na was assessed by the analysis of a certified reference material of milk (infant formula), and good agreement between the certified values and the measured value was obtained. The limits of quantification for the acid digestion with reflux system for Ca, Cu, Fe, K, and Na, in milligram per kilogram, were 7.48, 0.31, 1.0, 8.20, and 25.81, respectively, and for the microwave digestion were 14.0, 0.57, 1.78, 14.65, and 46.08, respectively. The decomposition procedure using a cold finger in an open system is effective, presenting the lowest residual carbon content (6 %), good accuracy, and relative standard deviation lower than 5 %, and appears to be a suitable procedure for sample preparation for routine analysis. [ABSTRACT FROM AUTHOR]

Given the importance of reference materials (RM) in the structuring and maintenance of quality management systems for food analysis laboratories, RM were produced for the measurement of moisture, ash, total fat, and titratable acidity in whole milk powder. Two types of packaging and three storage temperatures were evaluated. The RM were considered homogeneous. The materials that were packaged in the pouches and those packaged in the amber glass bottles with screw caps (stored at room temperature) were not stable for moisture. Nevertheless, considering the four measurands, the amber glass bottles under refrigeration and freezing temperatures were the best packaging and storage conditions, respectively. Homogeneity and stability studies were carried out according to the ISO Guide 35, IUPAC harmonized protocol, and ISO 13528, considering the potential applicability of the produced materials as certified reference materials or even as RM for use in proficiency testing schemes. For homogeneity, despite the different criteria, there was agreement between the results. Considering the stability, the agreement depended on the evaluation of the regression assumptions, which is not required by the ISO Guide 35. The contribution of uncertainty associated with homogeneity was greater than that related to stability. The results indicated that the produced materials, i.e., the candidate certified RMs, were suitable for assessing trueness and could be submitted to further inter-laboratory characterization. [ABSTRACT FROM AUTHOR]

A method was developed to determine melamine in milk powder and liquid milk by capillary zone electrophoresis after electrokinetic supercharging. The effects of buffer acidity and concentration, the type and length of leader and terminator electrolytes, injection time and matrix effects were investigated. The optimum background electrolyte was 50 mM sodium citrate-citric acid (pH 4.5), hydrodynamic injection of 50 mM sodium chloride (24 s, 0.5 psi) as leader, electrokinetic injection of the sample (100 s, 10 kV), hydrodynamic injection of 50 mM tetrabutylammonium bromide (18 s, 0.5 psi) as terminator and then a voltage of 25 kV for separation (+25 kV). Under these conditions, the sensitivity was enhanced 2285 times when compared to a normal hydrodynamic injection with the sample volume <3 % of the capillary volume. The detection limit for melamine with this electrokinetic supercharging (EKS) system is 0.7 ng/mL. The developed method was verified by analysing milk powder and liquid milk samples, and the recovery was 29.8 and 42.1 %, respectively. [ABSTRACT FROM AUTHOR]

Milk powder matrix is highly complex with significant amounts of lipids and proteins; thus, the determination of trace residues and contaminants in it often requires extensive sample extraction and preparation prior to instrumental analysis. An ideal preparation method is simple, less time consuming, and relatively inexpensive. It enhances the recovery and involves low consumption of toxic organic solvents. In this study, six sample preparation methods for milk powder were established and compared, including liquid-liquid extraction, organic precipitation, heavy precipitation, and three different solid-phase extraction (SPE) methods. The extraction recovery was evaluated by determination of six preservatives and sweeteners (benzoic acid, sorbic acid, natamycin, lysozyme, saccharin sodium, and aspartame) by HPLC-DAD in whole and skimmed milk powder samples. The results showed that the reproducibility of liquid-liquid extraction was not as high as the SPE method although the recovery was beyond 80 %; the organic precipitation and heavy precipitation gave poor recovery (below 20 %) of lysozyme; the highest recovery (>85 %) was achieved using the HLB cartridge compared to C18 and MAX cartridges. Therefore, the HLB cartridge was selected as the most appropriate sample preparation material for the determination of the six preservatives and sweeteners in milk powder samples by HPLC-DAD. [ABSTRACT FROM AUTHOR]

An effective wet digestion procedure for the determination of total iodine contents in milk powder samples was developed utilizing a high-pressure asher technique. The optimized method based on a two-stage digestion procedure. In the first stage, 500 mg samples were digested at 300 °C for 2 h using 15.2 mol L HNO (5 mL) and 30 % HO (3 mL). After the first digestion stage, digestion vessels were allowed to cool down and 1.2 mL of 20 % ( w/ v) NaSO solution was added as an additional oxidizing agent to the samples. After that, the vessels were closed, and they were heated at 100 °C for 30 min, resulting in clear and colorless sample solutions. Iodine concentrations in the digested samples were measured with inductively coupled plasma mass spectrometry. The accuracy of the optimized method was confirmed by analyzing milk powder reference material (BCR-151, milk powder). The obtained value for iodine (5.29 ± 0.37 mg kg, n = 6) was in good agreement with the certified value (5.35 ± 0.14 mg kg). Furthermore, the results obtained for reference material showed that the developed method can be applied also for the determination of other elements, e.g., copper, iron, and lead in the digested milk powder samples. [ABSTRACT FROM AUTHOR]

Sensitive ingredients of food, pharmaceutical products, or bioproducts can be damaged due to inappropriate processing conditions. The knowledge of the kinetics of degradation reactions allows optimizing production processes with regard to the nutritional quality. The essential amino acid lysine is an important nutrient in dairy powders that can be blocked, e.g., due to the Maillard reaction during drying processes. In this study, we showed that lysine loss can be modeled with pseudo-second-order reaction kinetics. The reaction rate constants increased with increasing temperature. At 90 °C, the highest reaction rate constant was found at a water activity of 0.23. This maximum was shifted to higher water activities for lower temperatures. The temperature dependence of the reaction rate constants could be modeled by the Williams-Landel-Ferry equation in the vicinity of the glass transition temperature and in the rubbery state. The glass transition temperature was calculated with the Gordon and Taylor equation. At higher temperatures and water contents, Arrhenius-type behavior was determined. The activation energy E and the pre-exponential factor $$ k_0^{*} $$ of the Arrhenius equation were expressed as a function of the water content. Thus, it is possible to model lysine loss under conditions that are typical of the production of dairy powders as a function of the temperature, water content, and physical state. The established pseudo-second-order reaction kinetics model can be used to minimize lysine loss during the production of milk powder and to ensure a high nutritional quality. [ABSTRACT FROM AUTHOR]

A new detection method using headspace single-drop microextraction (HS-SDME) coupled to gas chromatography (GC) was established to determine the iodine in milk powder and urine. The derivative from the reaction between iodine and butanone in the acidic media was extracted into a micro-drop then determined by GC-ECD. With the optimisation of HS-SDME and derivatisation, the calibration curve showed good linearity within the range of 0.004-0.1 μg mL (0.004-0.1 μg g) ( R = 0.9991), and the limits of detection for milk powder and urine were 0.0018 μg g and 0.36 μg L, respectively. The mean recoveries of milk powder and urine were 90.0-107 % and 89.4-101 % with mean RSD of 1.7-3.4 % and 2.7-3.3 %, respectively. This detection method affords a number of advantages, such as being simple, rapid, and inexpensive, with low organic solvent consumption, and is remarkably free from interference effects, rendering it an efficient method for the determination of iodine in milk powder and urine samples. [ABSTRACT FROM AUTHOR]

We have synthesized silver nanoparticles (AgNPs) decorated with α-cyclodextrin (CD) by using the traditional silver mirror reaction in the presence of CD. The CD-AgNPs were used as substrate in surface-enhanced Raman spectroscopy (SERS) for determining melamine. The intensity of the Raman band of melamine at 704 cm was used to determine melamine in milk and milk powder. The use of CD-AgNPs as the SERS substrate rather than classical silver nanoparticles makes the method more sensitive in giving an enhancement by a factor of up to ~ 10 in scattering efficiency. The effects of the volume of solutions (of CD-AgNPs, NaCl, NaOH, melamine) and of mixing time were optimized. The standard addition method was employed for quantitative analysis. The correlation coefficient of the calibration plot is 0.9995, and the limit of detection is 3.0 μg L. The method was successfully applied to the determination of melamine in milk and milk powder, with relative standard deviations of <10 % and recoveries between 89 and 104 %. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Bacillus cereus is a food pathogen of major concern to the dairy industry. Strains of B. cereus were isolated in 2006 and 2010 from a pasteurized milk processing line in a dairy plant in Algeria. Pasteurized milk is obtained from reconstituted and processed milk powder. This study was designed to discriminate between the isolated B. cereus strains and to predict their food poisoning potential. Strains were fingerprinted by M13-PCR, and identified at the phylogenetic group level by amplified panC gene sequence analysis. They were clustered into three distinct M13-PCR groups: one major group which included 17 strains and two minor groups which contained two and one strains, respectively. Strains originating from both the process equipment and milk powder were from the major group indicating that milk powder was the main source of initial contamination. Strains from the major and second group were affiliated to the mesophilic phylogenetic group III while the unique strain of the third group was classified into the mesophilic phylogenetic group IV. The data presented in this study showed a very low genetic diversity among B. cereus strains identified in milk powder and secondly by milk processing systems, as well as persistence in the dairy environment of specific B. cereus genotypes, across 4 years. M13-PCR typing and phylogenetic affiliation were useful for characterizing B. cereus dairy isolates, permitting their differentiation within the B. cereus group, and showing homogeneous contamination throughout the pasteurized milk processing line. The recurrent genotypes which belong to the potentially toxigenic group III B. cereus could threaten pasteurized milk safety. [ABSTRACT FROM AUTHOR]

A new method for multi-residue determination of five synthetic glucocorticoids (betamethasone, dexamethasone, prednisone, prednisolone, and hydrocortisone) in milk powder is developed. The glucocorticoids in the samples were extracted with tert-butyl methyl ether under ultrasonication incubation, and then cleaned up through gel permeation chromatography. After C18 LC gradient elution separation using acetonitrile with 0.1% formic acid as a mobile phase, the eluents were determined by liquid chromatography-tandem mass spectrometry with multiple reaction monitoring and positive ionization modes. The effective separation for the five glucocorticoids was achieved. The limit of quantification of the method for testing five glucocorticoids in milk powder was in the range from 0.2 to 0.5 μg kg, which was lower than the maximum residue limits established by European Union for glucocorticoids in foods. Experiments on spiked samples of milk powder showed that the mean recoveries at addition level of 1.0, 3.0, and 5.0 μg kg were in the range of 71.2% and 103%, and the relative standard deviation ranged from 4.7% to 16.8%. The calibration curves for these drugs between 1.0 and 100 μg l showed good linearity, with correlation coefficient ( r) more than 0.999. The real sample test showed that this method is sensitive and accurate. It can be used for qualitative and quantitative determination of studied glucocorticoid residues in milk powder samples. [ABSTRACT FROM AUTHOR]

A pilot study (APMP.QM-P19) of the Asia Pacific Metrology Program for the determination of melamine at two different levels in milk powder was organized in 2010. It was the first interlaboratory comparison programme in measuring melamine in food matrices for metrology institutes in the region. Melamine was chosen as the target analyte because of the recent crises that happened in 2007 and 2008 had caused substantial concern from consumers, food manufacturers, policy makers on food safety and the food testing communities. The objectives of APMP.QM-P19 were to evaluate the testing capability of participants on the quantification of trace level melamine in milk and milk products and to investigate the degree of equivalence with respect to the assigned values. In total, 19 laboratories (11 metrology institutes and eight food testing institutes) enrolled in the study. Analytical techniques reported by participants included liquid chromatography with ultra-violet and tandem mass spectrometry, gas chromatography with high-resolution mass spectrometry and enzyme-linked immunosorbent assay. Dispersion of analytical data in the two test materials was significant, and normal Gaussian distribution of data was not observed. The median was agreed to be used as the assigned values in the programme. Metrology institutes who employed isotope dilution mass spectrometry technique were found to give more consistent results and higher degree of equivalence than others. The performance of most of the food testing institutes was not satisfactory, and they were encouraged to have a thorough review of their validation procedure and estimation of uncertainty. [ABSTRACT FROM AUTHOR]

Melamine made headlines in September 2008 because it was found to be the contaminant responsible for the deaths of several infants and making many more sick. Determination of trace melamine is very important. Therefore, in this work a novel, sensitive and reliable method was developed using differential pulse polarography. The most suitable buffer system was found to be Britton-Robinson (B-R) buffer, pH 11.2. The melamine peak in this medium appeared at about −50 mV, it responded well to standard additions and high reproducibility was obtained. The calibration graph was linear in the concentration range of melamine from 1.0 to 66.4 μM with a correlation coefficient of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were obtained as 0.3 and 1.0 μM, respectively. The current was characterized as being adsorption-controlled process. The proposed method was successfully applied to the determination of melamine in spiked milk and milk powder. The linear dynamic ranges observed for melamine concentration in milk and milk powder samples were between 1-58 and 10-57 μM, respectively. The sufficiently good recoveries and low standard deviations for the data reflect the high accuracy and precision of proposed differential pulse polarographic method. [ABSTRACT FROM AUTHOR]

The rationale of this study has been to produce stabilized dairy powders for longer-term ambient storage by partial crystallization of the sticky amorphous lactose component in vibrated fluidized beds. Various combinations of temperatures, humidities, and processing times were used to crystallize lactose and milk powder in a fluidized bed dryer/crystallizer to achieve different degrees of amorphicity of powder. Under these conditions, lactose crystallinity and the crystallinity of the lactose portion in milk powder were found to increase significantly compared with the amorphous powders that were produced by conventional spray dryers. Different analytical techniques were used to investigate the degree of amorphicity and the improvement in powder crystallinity, such as modulated differential scanning calorimetry, water-induced crystallization, and Raman spectroscopy. The resulting powders were not sticky and were produced by different experimental conditions of processing temperature as 50-70 °C and 40% relative humidity in 30-60 min processing time. This technique is able to crystallize amorphous lactose and lactose-containing powder after spray drying in a reasonable processing time. [ABSTRACT FROM AUTHOR]

Infant formulas (IFs) are major sources of proteins for the neonate when breast-feeding is not possible. Heat treatments used during IF manufacture affect the structure of milk proteins but the impact of these structural modifications on the digestion of milk proteins and the identity of the bioactive peptides released in the gut have never been studied so far. The objective of this work was to determine the impact of two technological parameters (percentage of dry matter of the milk concentrate prior to heat treatment and intensity of the heat treatment applied to it) considered as essential in IF manufacture on the resistance of milk caseins (CNs) to digestion. Six skim milk powders were manufactured by spray-drying after having submitted 25% or 35% dry matter milk concentrates to three types of heat-treatment traditionally used in industry (80°C/20 s, 85°C/180 s, 105°C/60 s). Those six samples and a reference unheated one were characterised (particle size, composition...) and submitted to an in vitro digestion model mimicking the gastrointestinal digestion of an infant. Digested samples were characterised by SDS-PAGE and western-blotting and by ELISA using a collection of 23 αs, αs, β and κ-CN-specific monoclonal antibodies. Kinetics of β-CN hydrolysis was studied by antibody arrays. Peptides resisting to digestion were identified using mass spectrometry. Heat-treatment of milk prior to spray-drying was shown to significantly increase the residual CNs immunoreactivity monitored after digestion. Areas showing either post-translational modifications or high hydrophobicities were identified as being the most resistant to digestion whatever the process studied was. [ABSTRACT FROM AUTHOR]

The exposure to perfluorinated compounds (PFCs) through the diet for humans is of great concern. Among the diet, dairy products are in great demand. This paper reports the study on the levels of 9 perfluorinated acids and 2 fluorotelomer acids in milk, milk powder and yoghurt purchased from Chinese markets from 2008 to 2009. The analytes were quantitated by high performance liquid chromatography/electrospray tandem mass spectrometry (HPLC-ESI-MS/MS). In milk samples, perfluoroheptanoic acid (PFHpA) and perfluorononanoic acid (PFNA) were detected frequently, both in 68% of samples. In milk powder samples, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and PFNA were the only detected PFCs and none of them was observed in more than 35% of samples. In yoghurt, PFOA was the most frequently detected compound, found in 69% of samples. None of fluorotelomer acids was observed in any samples. The mean concentrations of total PFCs were 178 pg/g (wet weight) in milk, 98 pg/g (dry weight) in milk powder and 42 pg/g in yoghurt (wet weight). It is notable that the data of this study indicate significant differences (P<0.001) among three kinds of packaging of milk in the concentration of total PFCs. A preliminary human health risk assessment of milk and dairy products consumption was conducted in this study. For adults, the mean daily intake of PFOS and total PFCs was equal to or lower than 23 and 167 pg kg-1 d-1 (body weight), respectively. [ABSTRACT FROM AUTHOR]

A simple and quick (less than 5 min/pellet) method for the quantification of a series of macroelements (Na, Mg, P, Cl, K, and Ca) and trace elements (Fe, Cu and Zn) by wavelength dispersive X-ray fluorescence (WDXRF) has been established and validated for fortified milk powders, from a single production site. The calibration set of 23 samples was selected to uniformly cover the concentration ranges of each element. The validation set was composed of 32 samples. By using a high power WDXRF instrument, a counting time as short as 20 s for most of the analytes can be used to considerably decrease analysis time. Reference values obtained by inductively coupled plasma-atomic emission spectroscopy and by potentiometry for chloride were used to calibrate the WDXRF system. Subsequently, the WDXRF results were evaluated against those obtained from the reference methods. The results show good performance of the WDXRF method for routine analysis of milk powders including copper at low levels (<10 mg/kg). All the calibrations gave R 2 > 0.98, while all validation work has been done using three replicates of each sample; the results have additionally been reassessed to check that only two replicates per sample would not lead to significant differences in terms of quality of data and could be considered for routine analysis to further decrease analysis time. [ABSTRACT FROM AUTHOR]

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The mycotoxin aflatoxin M1 (AfM1) is a serious food safety hazard for which the European Commission has already established a maximum permissible level of 0.05 μg/kg AfM1 in milk and products thereof. For control analysis laboratories are increasingly asked to submit full uncertainties of their analytical results. The evaluation of measurement uncertainties of an analytical method for the determination of AfM1 in milk and milk powder on the basis of ‘in-house’ validation data in compliance with the ‘Guide to the Expression of Uncertainty in Measurement (GUM)’ [1] and the ‘EURACHEM Guide’ [2] is described. A similar approach will be used to assess the performance of methods employed by laboratories participating in the certification of reference materials for AfM1 in milk powder. [ABSTRACT FROM AUTHOR]

In the past few years, there has been an upsurge of interest in aluminum (Al) and human health. The well-recognized manifestations of systemic Al toxicity include fracturing osteomalacia, dialysis encephalopathy, and microcytic hypochromic anemia. The role of Al in causing childhood diseases is also becoming clearer, but the safe plasma level still remains to be determined in newborns, especially in premature newborns, implying that it should be kept low. Premature infants receiving iv fluid therapy show evidence of Al loading. Additionally, the infant-feeding mixtures, especially the soy-based infant formulas, tested may be a significant additional source of Al in the diet of infants with low birthweights, and in infants and in young children with impaired renal function. Careful clinical and biochemical monitoring is warranted to determine whether it will be necessary to eliminate Al contamination of both oral and parenteral preparations used in infants and children who may be at risk for Al intoxication. In this present study, the Al content of infant feeds was measured by electrothermal atomic absorption spectrophotometry, and also compared with those of breast milk, cow's milk, milk powder, and some starches that are commonly used for preparation of infant feed in Turkey. Our results show that Al content of commercially available powdered infant formulas, most of which are imported from Europe, ranged from 1.211 to 10.925 μg/g. The mean value was higher than that of breast milk. It was also found that the Al content of cow's milk in various containers was higher than that of breast milk. The highest Al level among cow's milk samples was in the aluminized carton box. In the other products tested, such as milk powder, the starches contained Al at various levels. Among these, milk powder and rice flour contained a high level of Al. [ABSTRACT FROM AUTHOR]

This paper describes a third-order derivative Spectrophotometric procedure for the determination of traces of phosphate, based on the formation of a ternary ion-association complex by reaction of phosphate with rhodamine 6G in the presence of molybdate. The pink complex is readily formed in 0.08-0.16 M HSO medium and remained stable for 2 h. The influence of various instrumental parameters and reaction conditions for maximum colour development are discussed. The few interfering ions can be masked by the addition of appropriate reagents. The procedure is simple, rapid and reliable and allows the determination of 1.5 μg l of phosphate. The relative standard deviation for the determination of 0.08 mg l of phosphate was 1.1%. The method is applicable to the determination of phosphate in river water, sea water, drinking water, milk powder and standard reference materials. [ABSTRACT FROM AUTHOR]

A simple and highly selective spectrophotometric method is described for the determination of nitrite. The method is based on the measurement of decrease in absorbance at 525 nm of rhodamine 6 G in sulphuric acid medium. The decrease in absorbance is instantaneous on addition of nitrite and remains stable for 2 h. Linear calibration graph passing through the origin was obtained in the range 0.01-0.6 μg/ml nitrite. The method is free from interference of Cu, Fe and SO which normally interfere in other procedures. The method was applied successfully to the determination of nitrite in well and sea water samples and in KNO, NaNO, table salt, sugar and milk powder samples. [ABSTRACT FROM AUTHOR]