Keifer question

[Major Nikon]

1. Both are the same in terms of bacteria count

The difference is how it's pasteurized. "ultra" means it's been pasteurized using a very high temperature for a very short period of time. Other methods use lower temperatures and longer periods of time to achieve the same bacteria reduction.

The reason UHT pasteurized milk is generally avoided for fermented dairy products like kefir is because the high temperatures involved denature the whey proteins in ways that interfere with coagulation.

The reason it's hard to find dairy that isn't UHT is because the shelf life is greatly increased. So many dairy manufacturers have pretty much exclusively switched to UHT and non-ultra pasteurized products are becoming much harder to find.