Could lightning sour milk?

17 May 2016


Lightning bolt in the sky



Does lightning sour milk? My uncle was a dairy man and he said yes but I am a scientists and I just don't see it. However, we just had a series of storms go through and a half a gallon of milk soured. Humm. We never have milk sour. It is making me wonder.


Gerry Gilmore got to grips with this old wives tale...

Gerry - It's really interesting this one. It's a classical old wives tale in the sense of old wives being established wisdom, and it goes back hundreds of years.

It became a major research endeavour in the late 1800s with hundreds of scientific papers written on the subject and it turned out it's true, or at least it was true! 

The reason is that lightning - it's a classic case of associating the dramatic variable with the answer when, in fact, there's some much more prosaic fundamental thing going on - the fundamental prosaic thing going on is first that in lightning storms you tend to have rain, and rain brings down germs and bugs and spreads them, out of the atmosphere.

Secondly, it happens in warm weather. So in the days before pasturisation and refrigeration, dairying was a marginal business and you took your life in your hands by eating milk and, in fact, it did go sour.

It was a well established phenomenon over millennia. All that changed about the year 1900 as pasturisation and refrigeration and it should no longer happen if reasonable sanitation applies.


There is plentiful anecdotal evidence of milk curdling, but not going sour, very quickly during a thunderstorm. The explanation above doesn't seem to work for that. Has any more recent research been done?

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