The invention of plastic plate for the semiquantitative detection of somatic cells in farm bulk tank milk

Bulk tank milk somatic cell count (BTM SCC) is worldwide acceptable as an indicator of subclinical mastitis and milk quality at the farm level. Several countries determine the BTM SCC level for quality control and milk pricing. In Thailand, BTM SCC standard is set at 500,000 cells/ml and premium milk quality is set at less than 100,000 cells/ml. Milk collecting centers (MCCs) use CMT (California Mastitis Test) for screening raw milk quality. However, CMT has an error and high variation. This study aims to invent a new semiquantitative device for determining BTM SCC and to validate the device in comparison with FossomaticTM FC and CMT. The results showed that the use of a specifically designed plastic plate with a mixture of specific chemical reagents and BTM is able to discriminate a semiquantitative BTM SCC according to reading scores 0,1,2 and 3. The reading scores is significantly correlated with FossomaticTM FC (r=0.80, p<0.05) and CMT (r=0.94, p<0.05) at the laboratory testing. At MCC, this new semiquantitative device is able to determine BTM SCC in which the test reading is correlated with the FossomaticTM FC (r=0.85, p<0.05). The accuracies of the test device are equal to 91.18% (95%CI = 93.66% – 98.19%) at SCC level less than 100,000 cells/ml and equal to 96.41% (95%CI = 87.42% – 94.10%) at SCC level more than or equal to 500,000 cells/ml.