Thunderstorms curdle milk

[snopes]

Comment: I have heard that lightening or thunderstorms can spoil or curdle
milk, and you're the only sourse I trust for the answer. I tried a search
here but didn't come up with results.

[Avril]

Is the idea that the lightning strikes the milk? Because I've lived through a lot of thunderstorms and I've never had any problem with it spoiling my milk--unless it knocks the power out.

[Singing in the Drizzle]

Lighting storm today and my milk is still good. It would be nice if they provided a range for maximum distance that lighting will have to strike from the milk in order to spoil it. Then we can find some one to test it.

[Avril]

O.K., I found an article in the Nashua, New Hampshire Telegraph on this, from 1937, entitled Thunderstorm-Curdled Milk Puzzle Still Baffles Science:

The results yet obtained are not sufficiently conclusive ... but it has been discovered that ionization has no effect at all on the decay of meat or the curdling of milk.

But people were also wondering about this in the nineteenth century. The Colorado Medical Journal published an article in 1897, saying that it was the warm weather, not the storms. (Which makes sense. Prior to refrigeration, your milk would seem more likely to curdle in thunderstorm weather than in, say, blizzards.)

One can find similar arguments in this 1918 book, Agricultural bacteriology.

This source, another same-era publication, suggests that in the 1860s, people thought that milk soured during thunderstorms because of ozone.

So it's an old one. But it does seem to be talked about quite a lot.

ETA: New Scientist took it up in the 1990s, but I can't access the artice.