Based on online reading, it seems like decreasing PH to < 4.5 is the way to reduce spore-former activity.

Is it possible to decrease the pH of milk without significantly affecting its taste and not letting it curdle?

I have thought about using an emulsifier to potentially prevent curdling, and am thinking about various kinds of acid (gluconic/lactic) that may be less strong in taste than citric. Any suggestions?

  • What are you trying to achieve?
    – SAJ14SAJ
    Dec 22, 2012 at 21:08
  • I want to make a shelf-stable chocolate milk
    – Ihsir
    Dec 22, 2012 at 21:15
  • Suggest you change your question to that, specifically. However, I suspect that is somewhere between impractical and unbelievably difficult with home type equipment.
    – SAJ14SAJ
    Dec 22, 2012 at 21:17
  • 1
    The acidity is only about botulism spores. There are many bacteria which thrive in food, you would have to sterilize and can the milk to prevent any other bacteria from growth before you can start thinking about botulism. Also, different foods need different temperatures to be sterilized, a home pressure canner is probably not good enough for milk.
    – rumtscho
    Dec 23, 2012 at 21:49

1 Answer 1


The major protein in cow's milk, casein precipitates at pH 4.6. It matters very little which acid you use to get to 4.6, casein will still precipitate. pH 4.6 is about the same acidity as canned beets, a food not known for its tartness, so you won't achieve a very sour flavor before things start curding up on you. Adding emulsifiers could help some with the isoelectric precipitation, but emulsifiers have flavors too, and you'll have to add them at a not insignificant fraction of the protein (casein) concentration.

For shelf stable chocolate milk, I'd go with a mix of powdered milk and cocoa powder; just add water. All the storebought room temp chocolate milk products I've seen are ultrapasturized or similar.

  • 1
    +1 for the powdered idea--I used to do this for homemade hot chocolate mix with great success. This is probably the most feasible way to do it at home, although it probably isn't what the OP was thinking of.
    – SAJ14SAJ
    Dec 23, 2012 at 4:46

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