Raw Milk Testing

Are you ready to start testing?

Since 2008, Microbial Research Inc. has partnered with raw milk producers to deliver reliable microbiological testing that supports confidence in product safety and quality.

Our testing program—developed in collaboration with raw milk producers—is designed to efficiently and accurately measure total bacterial counts and screen for key pathogens, all at an accessible cost.

We provide timely, professional, and clear reports designed to support producers in communicating results to their clients. Our knowledgeable laboratory team is available to provide guidance on result interpretation and assist with any necessary troubleshooting.

Description of Tests:

Campylobacter:

This test screens milk for the presence of Campylobacter, a harmful bacterium that can cause serious illness. Young children, older adults, and people with weakened immune systems are especially vulnerable. Safe milk should not contain detectable Campylobacter.

Coliforms:

This test measures the total coliform count in the milk. Coliforms are Gram-negative, rod-shaped bacteria capable of growing with or without oxygen. They are non-spore forming and ferment lactose. Common genera include: Escherichia coli, Klebsiella, and Enterobacter. Coliforms are found in a variety of environments including water, soil, plants, and the digestive tract of animals. Because of their presence in both fecal and environmental sources, coliforms serve as indicators of possible contamination - from poor sanitation, unclean equipment, environmental exposure, or inadequate washing and handling. Coliforms can also cause mastitis in animals. The lower limit of detection for this test is 0 CFU/mL, and the recommended maximum threshold for raw milk is 10 CFU/mL from the Raw Milk Institute.

Escherichia coli O157:

This test identifies the presence of E. coli O157 in milk. E. coli O157 is a serious pathogen that can cause severe illness, particularly in young children, the elderly, and individuals with weakened immune systems. No E. coli O157 should be present.

Listeria:

This test detects the presence of Listeria species in milk. Certain Listeria species, including Listeria monocytogenes, are important foodborne pathogens that can cause serious illness, particularly in pregnant individuals, newborns, older adults, and people with weakened immune systems. The presence of pathogenic Listeria in milk is considered unacceptable.

Mastitis Screening:

This test identifies pathogens associated with mastitis in milk, helping producers determine the cause of infection and make targeted decisions for treatment, prevention, and herd health management. Early and accurate pathogen detection can improve animal welfare and reduce economic losses.

Salmonella:

This test is used to detect the presence of Salmonella in milk samples. Salmonella is a harmful pathogen known to cause serious illness in humans. No Salmonella should be present.

Standard Plate Count (SPC):

This test measures the total number of bacteria that can grow in the presence of oxygen, providing an overall assessment of the milk’s bacterial load. Elevated counts may indicate inadequate sanitation, improper cooling or handling, milk that is no longer fresh, or the presence of illness in the animals. The test has a detection limit of 20 colony forming units (CFU) per milliliter. For high-quality raw milk, the Raw Milk Institute recommends the SPC should be below 5,000 CFU/mL. If the SPC exceeds 100,000 CFU/mL, additional testing for Staphylococcus and Streptococcus detection may be performed to help identify potential infections in the herd.