With my new pH meter I am finally able to start monitoring pH of my raw Jersey/Brown Swiss milk. I've read about normal pH ranges, and also about how temperature affects the pH reading. For example, Caldwell demonstrates in her pH video that the pH can drop about 0.1 when measuring milk at 40 F and ~90 F, respectively.
Unfortunately, most pH numbers are presented without corresponding temperatures. So when I read that "normal milk pH is between 6.5 and 6.7", at what temperature is that? And on another note, is that range specifically 6.50 to 6.70 or 6.50 to 6.79?
It's commonly stated that if pH is above 6.7 then that might mean the cow has mastitis. But then, there is no reference temperature associated with that number. Caldwell mentions in her book to be concerned about mastitis if milk pH is 7.0 or higher. Then I read a scientific dairy experiment where pH was measured on raw milk and it was 6.8-6.9 @ 75 F and it was considered "Grade A milk". So I'm finding different numbers for the threshold of "suspected mastitis".
The reason I'm digging deep into this, is that my milk is measuring somewhere around 6.83 @ 40 F, and 6.73 @ 90 F. I'm not sure whether or not to be concerned, as these numbers may (or may not?) be in the neighborhood of what might flag "suspected mastitis".
I'm also wondering if environmental factors, such as high alkaline soil and water, can influence the milk pH.
Any thoughts on any of this from you dairy folks out there would be most appreciated.