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Major and trace elements in organically or conventionally produced milk
John E Hermansen1, Jens H Badsberg, Troels Kristensen
1Danish Institute of Agricultural Science, Department of Agroecology, PO Box 50, 8830 Tjele, Denmark. John.hermansen@agrsci.dk
The Journal of Dairy Research
|September 22, 2005
Summary
This study analyzed 480 milk samples for trace elements, finding organic milk had higher molybdenum and lower barium, europium, manganese, and zinc than conventional milk. Breed also influenced mineral content.
Area of Science:
- Environmental Science
- Food Chemistry
- Analytical Chemistry
Background:
- Understanding the elemental composition of milk is crucial for assessing nutritional value and potential environmental contaminants.
- Variations in milk's trace element profile can be influenced by farming practices (organic vs. conventional) and animal breed.
Purpose of the Study:
- To quantify and compare the concentrations of 45 trace elements and 6 major elements in milk from organic and conventional dairy farms in Denmark.
- To investigate the influence of dairy cattle breed (Danish-Holstein vs. Jersey) on milk's elemental composition.
- To establish typical concentration ranges for elements with limited available data in milk.
Main Methods:
- Analysis of 480 milk samples from 20 farms (10 organic, 10 conventional) over one year using high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES).
- Strict contamination-free conditions were maintained throughout sampling, preparation, and analysis.
- Statistical analysis was performed to identify sources of variance and test differences between production systems and breeds.
Main Results:
- The week of sampling was the primary source of variation for most elements.
- Organic milk showed significantly higher concentrations of molybdenum (Mo) and lower concentrations of barium (Ba), europium (Eu), manganese (Mn), and zinc (Zn) compared to conventional milk.
- Jersey cows produced milk with higher concentrations of several elements, including calcium (Ca), iron (Fe), and zinc (Zn), compared to Danish-Holstein cows.
- Concentrations of arsenic (As), cadmium (Cd), chromium (Cr), manganese (Mn), and lead (Pb) were lower than published ranges, while cobalt (Co) and strontium (Sr) were higher.
Conclusions:
- Farming system and breed significantly impact the elemental profile of milk.
- This study provides valuable data on typical concentrations of numerous trace elements in milk, including those with previously scarce information.
- The findings contribute to a better understanding of milk's complex elemental composition and factors influencing it.