Raw Milk Testing

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Microbial Research Inc. works alongside Raw Milk Association of Colorado (RMAC) to provide their members with reports on the microbiological nature of their products.

Below is a brief explanation of the routine testing performed for RMAC. The process for each test is explained in more detail on each individual dairy report. Testing is designed to quickly, accurately, and cost-effectively determine the overall number of bacteria present in a milk sample and test for select pathogens.

Routine Tests:

Standard Plate Count (SPC):

This is an overall count of bacteria that can grow in the presence of oxygen in order to assess the overall bacterial load in the milk. Higher counts generally indicate improper sanitization, improper cooling or handling of the milk, older milk or diseased animals. The lower limit of detection for this test is 20 colony forming units (cfu)/mL. The RMAC threshold for good milk quality requires the SPC count to be <15,000 cfu/mL. If the SPC is >100,000 cfu/mL, the sample is then tested for Staphylococcus and Streptococcus to help the producer determine if there is an infection occurring in the animals producing the milk

Salmonella:

This test detects salmonella in the milk. Salmonella is a pathogen capable of causing significant disease in humans. The lower limit of detection for this test is 0 cfu/mL. The RMAC limit is 0 organisms.

Escherichia coli O157:

This test detects E. coli O157 in the milk. E. coli O157 is a pathogen capable of causing significant disease in humans, especially in children and the elderly or other immunocompromised individuals. The lower limit of detection for this test is 0 cfu/mL. The RMAC limit is 0 organisms.

Coliforms:

This test enumerates the total coliform count in the milk. Coliforms are Gram-negative rod shaped bacteria that can grow in the presence or absence of oxygen. They are non-spore forming bacteria that ferment lactose and generally include the following bacteria: Escherichia coli, Klebsiella, and Enterobacter. Coliforms are found in multiple reservoirs such as water, soil, intestinal tract and non-fecal origin. Coliforms are used as indicator organisms for fecal contamination, non-fecal origin contamination such as equipment, environment, insufficient food washing, sanitizing, etc. Coliforms can also cause mastitis in animals. Not all E. coli are pathogenic. In fact, it is beneficial to have non-pathogenic E. coli present in the intestinal tract of a healthy person. The presence of normal flora helps to prevent the intestinal colonization of a pathogen. The lower limit of detection for this test is 0 cfu/mL. The RMAC limit for this test is 50 cfu/mL.