1985 Volume 56 Issue 3 Pages 215-220
Total milk solids (or solids not fat) content of milk is one of the important factor that compositional quality payments are based on. Total milk solids content of milk may be obtained by the summation of the correction value and fat, protein and lactose values measured by infrared milk analysis instrument. This correction value was examined in this article. Samples from bulk milks (28 samples/month) and individual milks (about 70 samples/month) were collected in Ibaraki and Chiba prefectures during 13 months, and were analyzed for their fat, protein and lactose with Milkoscan 203 B (Foss Electric co. ) and also analyzed for their total milk solids with TMS-Checker K 375 A (Anritsu co.). The reference methods for the calibration of these instruments were Gerber, macro-Kjeldahl, Lane-Eynon method and the standard gravimetric method, respectively. The alpha-values, or the correction values, were calculated by subtracting fat, protein and lactose (anhydrous) values from TMS values, and their variations were examined. As for bulk milks, results showed little seasonal or regional variation (mean 1.04%, s. d. 0.066). This indicates that the correction value could be added to fat, protein and lactose (anhydrous) values, measured by infrared milk analysis instrument, to obtain a TMS value. The alpha-value of individual milks had a little more bigger seasonal or regional variation (mean 1.07%, s. d. 0.105) than that of bulk milks. However, the correction value could be added to the values determined by the instrumental method, to estimate a rough TMS value of a individual milk sample rapidly and simply. In order to estimate TMS-content with better accuracy and precision, the following items should be mentioned: 1. the origin of the samples, i. e. bulk milk or individual milk, 2. lactose content expressed as anhydride or as monohydride, 3. the reference methods used for the calibration of the instrument and the level of the calibration, and 4. the limits of the application (e. g. applicable place, reliable period etc.) of the correction value.
