Estimation of SNF content in milk

ESTIMATION OF SNF CONTENT IN MILK

Gravimetrically Solid not fat content of milk can be estimated by assessing the total solid content and  subtracting the fat percentage. Total solid content can be estimated by

  • Gravimetrric method
  • Using Formula method (Richmonds’s or, Babcock’s, or Fleismann’s method, BIS/ISI method )
  • Using Richmond’s sliding rule. Originally ISI formula as given below was followed

         %SNF = CLR/4 + 0.25F + 0.6 and   % SNF =  %TS - % F 

              Thus, % T.S   = %SNF+% Fat = CLR/4 + 1.25F+ 0.6

 Where CLR is the corrected lactometer reading and “F” is the fat percentage of milk sample. For calculating the CLR, lactometer is allowed to float freely and the reading is taken. The temperature of milk is also noted. Normally the lactometer reading should be noted at the temperature calibration of lactometer. In practice the temperature of milk varies and hence it has to be corrected. As per amendment No 1 Feb 1992 to ISI 10083:1982, the following formula and correction factor are to be used for determination of SNF in milk by the use of ISI lactometer

SNF =CLR/4 +0.25F+0.44

The LR correction at a temperature (19 C to 35 C) and fat (0 to 8 percent) is given as under       

TEMPERATURE

     FAT PERCENT OF SAMPLE

0 %

2 %

4%

6 %

8 %

19.0 -2.2 -2.4 -2.6 -2.7 -2.9
19.5 -2.1 -2.3 -2.4 -2.6 -2.7
20.0 -2.0 -2.1 -2.2 -2.4 -2.4
20.5 -1.8 -2.0 -2.1 -2.2 -2.3
21.0 -1.7 -1.8 -1.9 -2.0 -2.2
21.5 -1.5 -1.7 -1.7 -1.9 -2.0
22.0 -1.4 -1.5 -1.6 -1.7 -1.8
22.5 -1.3 -1.4 -1.4 -1.5 -1.6
23.0 -1.1 -1.2 -1.3 -1.4 -1.4
23.5 -1.0 -1.1 -1.1 -1.2 -1.3
24.0 -0.8 -0.9 -1.0 -1.0 -1.1
24.5 -0.7 -0.8 -0.8 -0.9 -0.9
25.0 -0.6 -0.6 -0.6 -0.7 -0.7
25.5 -0.4 -0.5 -0.5 -0.5 -0.5
26.0 -0.3 -0.3 -0.3 -0.3 -0.4
26.5 -0.1 -0.2 -0.2 -0.2 -0.2
27.0 0 0 0 0 0
27.5 0.1 0.2 0.2 0.2 0.2
28.0 0.3 0.3 0.3 0.3 0.4
28.5 0.4 0.5 0.5 0.5 0.5
29.0 0.6 0.6 0.6 0.7 0.7
29.5 0.7 0.8 0.8 0.9 0.9
30.0 0.8 0.9 1.0 1.0 1.1
30.5 1.0 1.1 1.1 1.2 1.3
31.0 1.1 1.2 1.3 1.4 1.4
31.5 1.3 1.4 1.4 1.5 1.6
32.0 1.4 1.5 1.6 1.7 1.8
32.5 1.5 1.7 1.7 1.9 2.0
33.0 1.7 1.8 1.9 2.0 2.2
33.5 1.8 2.0 2.1 2.2 2.3
34.0 2.0 2.1 2.2 2.4 2.5
34.5 2.1 2.3 2.4 2.6 2.7
35.0 2.2 2.4 2.6 2.7 2.9
 

Result

  • The SNF percentage in the given sample of cream is = --------
Last modified: Tuesday, 17 April 2012, 9:54 AM