Boil a small sample and observe whether it curdles abnormally
Drop a few drops on a clean, polished surface and see if it flows smoothly without leaving a white trail
Put a drop on the thumbnail and check whether it spreads slowly and evenly
Shake the milk and look for a thick, stable foam that may indicate added detergent
Add a few drops of iodine to check for starch
Add a few drops of nitric acid to check for added urea or other adulterants
Mix with water and use a lactometer to check density
Let the milk stand and observe whether cream rises normally
Smell the milk for any unusual odor
Taste a small amount to check for unusual sweetness, saltiness, or bitterness
Use a milk testing kit for fat, protein, and adulterant detection
Check the expiry date and packaging integrity
Compare the color and consistency with normal milk
Heat a small sample and see whether it forms a normal skin without excessive residue