Transmission Electron Microscopy Study of Casein Micelle in Raw Milk with Different Somatic Cell Count Levels

Abstract

The relationship between elevated raw milk somatic cell count (SCC) and casein micelle dimension was investigated by transmission electron microscopy (TEM). Milk samples collected from the dairy cattle with three different levels of SCC (<200,000, 200,000 to 800,000, and >800,000 cells/ml) were studied by TEM. The results indicated that an increase in SCC resulted in a decrease in the casein micelle size with an increase in their aggregation. The present research supported the hypothesis that elevated proteolytic activity, reduced secretary ability of the mammary glands, lower electrostatic and steric repulsion as well as different mineral contents of mastitic milk could affect casein micelle properties.

Keywords:

• Somatic cell count
• Transmission electron microscopy
• Raw milk
• Casein micelle

ACKNOWLEDGMENTS

The authors would like to thank Iran Dairy Industries Company (Pegah) for financial support of this research and Dr. Kambiz Shamsi for his valuable guidance.