When it is not possible to collect and examine a large number of samples for bacteria examinations, an indication of the sanitary condition of the milk can be obtained by:

Both the methylene blue reduction test and the resazurin test serve as rapid indicators of the sanitary quality of milk by assessing the presence and level of bacteria.

The methylene blue reduction test evaluates the milk’s ability to reduce methylene blue dye, which indicates the presence of bacteria that can consume the oxygen in the milk; a quicker reduction time suggests a higher bacterial load and potential spoilage. Similarly, the resazurin test measures the ability of the milk to reduce resazurin, which changes color based on the milk's bacterial activity. A significant presence of bacteria results in a faster change in color, indicating compromised quality.

Using either of these tests can effectively estimate milk quality when a large number of samples cannot be collected and analyzed, making the combination of both tests an efficient approach to assessing the sanitary condition of milk.