< food analysis:quality control of milk:quality control parameter of milk:organoleptic test:determination of pH of milk:clot on boiling test:methylene blue reduction test:mbrt test:determination of acidity of milk
  milk  

 
 
  • Organoleptic test

  Organoleptic test are used in the whole dairy and an experienced person can with out bad sample with a high degree of accuracy smell the milk in the container immediately after removing the lid. In case of foul or abnormal smell reject the milk or hold over for confirmatory test observe the color if abnormal it should be regard with suspension those due to developed acidity yhe most important factor to be examine those to be feed or exposal of milk to the atmosphere those with the exteriors matter oxidized flavor due to exposal milk to light or mechanical contamination.

  • Determination of pH

  The pH can be determined by pH meter.

  • Clot on boiling test

  Take about 5ml of milk in a test tube heat the tube in a boiling water bath for about 5 minutes, remove the test tube and examine the film of milk or side of the test tube for any precipitated particles. The formations of a clot or precipitate indicate a positive reaction. Milk either remains unchanged of coagulated milk which gives a positive COD as acidity, generally above 0.17% and is not suitable distribution or processing.

  • Half hour methylene blue reduction test

  Take about 10ml milk in a sterilized test tube add 1ml of methylene blue solution keep the solution in a boiling water bath inspect the tube after 30 minutes the sample which show complete decoloration of blue color on incubation for 30 minutes or less shall not be suitable for accepted.

  • Determination of acidity

  Lactometer is used to determine the density of milk the density of milk the zee led lactometer is calibrated at 29C and when the density is determined at a temperature other than 29C a temperature corruption should made to lactometer. If the lactometer reading done below 29C 0.3 should be subtracted from the lactometer reading for every degree of decreasing temperature. If the degree is done above 29C 0.3 is added to the lactometer for every degree increasing temperature this is called corrected lactometer reading.