What is the milk test? A probiotic supplement is added to approx. 4oz of milk and left to sit at room temperature for 24-48 hours. If the milk curdles to a yogurt-like consistency, the probiotics are considered live, viable and, thus, effective.  


Specific live probiotics have the ability to make milk acidic by fermenting lactose (the sugar in milk). The bacteria consume the lactose in the milk, turning it into lactic acid. The milk becomes more acidic and begins to curdle, making yogurt.  


Is the milk test reliable? It is true that certain probiotic bacteria can cause milk to clump, but, for a variety of reasons, not all probiotic bacteria will do this in the "milk test". To start with, the milk test only works with certain types of powdered or pill form probiotics where there is not a special coating that protects it from stomach acids. (Such a coating keeps the lactose from turning into lactic acid, thus not creating a yogurt-type consistency.) Additionally, a significant amount of lactic acid must be produced to curdle the milk. And lastly, not all strains of bacteria ferment lactose the same.


So what about MaryRuth Liquid Probiotics? The great news is our liquid probiotics are very much alive and viable, third-party certified and verified by three separate independent labs! MaryRuth Liquid Probiotics are uniquely and naturally wildcrafted, creating an enzyme-enriched substrate with a high pH balance. Due to this high pH, our plant-based probiotics do not have the ability to change lactose (in milk) into lactic acid. Lactic acid production lowers the pH of the milk which is what curdles the milk. Moreover, the high pH of the substrate allows the probiotic strains to withstand stomach acids and make their way to the small and large intestines, where they then work synergistically with the individual’s microbiome, secreting antiviral and antibacterial properties and aiding in the absorption of nutrients.