A Primo star optical microscope (Carl Zeiss, Germany) was used at 10 magnification for observation of the milk fat globules. Samples of milk (about 1–2 drops) were placed on a microscope slide and were left uncovered (without cover slip) to avoid destructing the native fat globules structure. Pictures of the samples were taken using a microscope digital imager at 10 magnification (Celestron, USA).