I have a bag of pink curing salt (Prague powder / instacure) #1 that has been in a cupboard since November 2019. It has been stored in its original packaging: a zip-lock style bag, which I have opened and resealed several times. The seal has been reinforced with a clip. The powder has now turned yellow, and I can't figure out why or whether it is still safe to use. Curiously, a plastic container containing a mix of the curing salt with sugar and 'regular' salt has kept its color, while being stored next to the bag of discolored salt.

I know the pink color comes from food coloring which could oxidise or be affected by light, but why would this only have happened to one of the two containers?

The discolored salt: enter image description here

The mix of curing salt with sugar and regular salt: enter image description here

  • Are there any changes in texture of the salt in the bag - I'm suspecting that the salt is hygroscopic and the pH in liquid form is affecting the dye. Or it could be photodegradation - though you say stored in a cupboard and the container hasn't seen changes
    – bob1
    Jun 30, 2020 at 20:54
  • @bob1 I'm not sure if the texture has changed (have not touched the bag in months), but it resembles slightly wet sand. Definitely no clumping, though, while the salt in the container has some fairly large chunks.
    – LSchoon
    Jun 30, 2020 at 21:08

2 Answers 2


That's our brand "Home Curing UK" or "Surfy's". The colouring used at that time was a natural colouring. Unfortunately the colour deteriorates over time due to the action of light and the nitrites, however the loss of colour does NOT in any way affect the efficacy of the product, 100% guaranteed.


Yes. The pink is a dye to distinguish it from regular table salt. So no worries about safety.

Here are two of the folks from America's Test Kitchen discussing it from 1:00 to 1:50.

  • Can you add any explanation or citations regarding the answer to the direct question about safety? Numerous resources explain the traditional pink in corned beef is a nitrate/myoglobin reaction, not from dyes, so I believe the side comment is simply incorrect.
    – Phil
    Jul 4, 2020 at 2:50
  • Sure. Check out 1:00 to 1:50 of the link above. But I've edited the comment to clarify.
    – hrokr
    Jul 4, 2020 at 2:56
  • @Phil The pink in the salt is from dye, the pink in the meat is from the nitrate/myoglobin reaction. There is obviously no myoglobin in the bag of salt ;)
    – LSchoon
    Jul 4, 2020 at 8:14
  • 1
    @hrokr Yes, the pink is a dye, but why does that mean there is no safety issue? If the dye has discoloured due to some change in the composition of the salt, that might be a problem, no?
    – LSchoon
    Jul 4, 2020 at 8:15
  • @LSchoon, both of those are the exact point I'm making... There's no reason to expect it to be safe, and the pink in the salt has nothing to do with the pink in the meat.
    – Phil
    Jul 4, 2020 at 17:00

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