Determination of lactose on filter paper preserved milk samples stored at different temperatures and periods : comparison with tube samples

The objective of this study was to determine the reliability of filter paper milk sampling milk method used for comparative measurements of the reproducibility with tube sampling milk. After performing a California mastitis test (CMT), the milk samples were collected on filter paper disks as well as in plastic tubes. The paper disks were preserved at different temperatures for 1 or 2 weeks, and the lactose was analyzed by a dinitrosalic acid method. Intra-sample reproducibility of the filter paper milk from the same individual was 13.6%, for the tube sampling milk 4.7%. There was no significant difference between results obtained from tube sampling milk and filter paper disk collected milk. Storage at different temperatures and for a varied period of time showed little change in lactose concentration of milk sample preserved in filter paper disks. There was a small decrease in concentrations of lactose in filter paper milk when compared to tubes collected milk and a high standard deviation probably because of loss in the extraction process. Milk collected on filter paper disks could be used to screen practically in milk lactose monitor.