Trace elements in milk

Milk and milk products form an important part of the human diet. They are analysed frequently for various components, e.g. for nutritional studies, and to comply with legislation controlling potential exposure to toxic elements. This section describes the preparation of a milk reference material (CRM 063R) which has been certified for a range of major and trace elements in replacement of a previous material (CRM 063) [29,30]. 

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For example trace elements in milk powder are not consumed as milk, and moisture in transformer oil is not used in transformers, yet matrix reference materials based on milk are imported as food and are subject to health certification requirements and sometimes import quotas. Likewise a matrix based on oil is identified as fuel or lubricating oil and is both classified as a hazardous material and subject to mineral oil tax. These problems arise because RMs are frequently incorrectly classified by specific title of their matrix (as Reference Material of Trace Elements in Rice is classified as rice) and not as reference material which is the intended use. 

In addition to the major salt constituents discussed up to this point, the elements listed in Table 1.3 have been detected in normal bovine milk by spectroscopic and chemical analyses. They include a large number of metals, the metalloids As, B, and Si, and the halogens F, Br, and I. The subject of trace elements in milk has been reviewed comprehensively (Archibald 1958 Murthy 1974 Underwood 1977). Their significance for human nutrition is discussed in Chapter 7. 

Murthy, G. K. 1974. Trace elements in milk. CRC Crit. Rev. Environmental Control 4, 1-37. 

J. A. Nobrega, Y. Gelina, A. Krushevska, R. M. Barnes, Direct determination of major and trace elements in milk by inductively coupled plasma atomic emission and mass spectrometry, J. Anal. Atom. Spectrom., 12 (1997), 1243D1246. 

The most significant differences are found for all major elements (e.g., Ca, K, Mg, Na, and P). However, the ratio Ca P, which is related to structural functions extremely important for the correct development of the newborn, is higher in human milk. Despite their low levels in milk, minor and trace elements play a central role in the organism, since their deficiency or excess may generate undesirable effects in the newborn. This fact and the centrality of milk in the human diet explain the growing interest in the determination of trace elements in milk [6-8], Table 13.6 summarizes the concentration levels for major, trace and ultratrace elements in human and cow milk. 

An overview of the application of atomic spectrometric techniques to the elemental analysis of milk samples has been given. Elemental composition of milk, its nutritional role, sample preparation methods for analysis and measurement techniques have been described in detail. It appears that ICP-MS and ICP-AES are the most reliable techniques for the multielemental analysis of major, minor, and trace elements in milk samples. 

L. Vuchkova, L. Margitova, S. Arpadjan, Comparative study on the determination of trace elements in milk powder and cheese products using modifier-free ETAAS and ICP-AES, Anal. Lab., 5 (1996), 41-45. 

E. Coni, S. Caroli, D. Ianni, A. Bocca, A methodological approach to the assessment of trace elements in milk and dairy products, Food Chem., 50 (1994), 203-210. 

E. Coni, A. Alimonti, A. Bocca, F. La Torre, D. Pizzuti, S. Caroli, Speciation of trace elements in milk by high-performance liquid chromatography combined with inductively coupled plasma atomic emission spectrometry, in S. Caroli (ed.), Element Speciation in Bioinorganic Chemistry, Wiley, New York, 1996, pp. 255-283. 

SUMMARY OF TECHNIQUES OF FINAL DETERMINATION USED IN THE CERTIFICATION OF MAJOR AND TRACE ELEMENTS IN MILK POWDER CRM 063R... 

CERTIFIED CONTENTS OF TRACE ELEMENTS IN MILK POWDER CRM 063R... 

Flynn A. 1992. Minerals and trace elements in milk. Adv Food Nutr Res 36 209-252. 

Environmental studies can be carried out in the atmosphere, in water, in sediments, on waste, in soil etc. It is possible to measure in the air, sediment, waste, soil and water directly or indirectly by collecting plants and animals from them. It is also possible to measure food prepared from animals living in a certain environment, e.g. enhanced levels of trace elements in milk, cheese or yoghurt. The environment may be defined on a number of different size scales. Sometimes large water and air masses are studied and sometimes limited indoor environments are under investigation. Sometimes local environmental problems are under study and sometimes global sources and sinks of chemicals are the subject. All this makes environmental studies very broad any chemicals in any medium over any kind of time resolution can be of importance. 

Anderson RR (1992) Comparison of trace elements in milk of four species. J Dairy Sci 75 3050-3055. 

Mingoeance MD and Lachia M (1985) Direct determination of some trace elements in milk by electrothermal atomic absorption spectrometry. Anal Lett 18 1519-1531. 

Byrne, A.R.. Kosta, L. Ravnik, V., Stupar, J. and Hudnik, V. (1979). A study of certain trace elements in milk, in Nuclear Activation Techniques in the Life Sciences 1978, IAEA, Vienna, 255-269... 

Minerals, including trace elements, in milk are compiled in Table 10.22. 

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