I've read that canned salmon typically does not contain any preservatives.

On the other hand processed meat (such as ham) contains them.

Why are preservatives needed in some cases but not others?

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    I am not sure I understand your question. Are you compared canned fish to some kind of canned meat, or are you comparing two totally different preservation techniques, like canning and curing, and asking why they are not done in the same way?
    – rumtscho
    Apr 27, 2019 at 11:59

2 Answers 2


These are two different ways to preserve food.

The canned salmon was boiled and then sealed into a can while it was still boiling sealed into a can and boiled under a specified combination of time and temperature that has been empirically proven to kill enough bacteria. All the bacteria in the can are dead, and no more can get in, so it's sterile and won't rot until it's opened.

The ham is preserved differently: instead of being sterile, it has enough preservatives that whatever bacteria get in can't grow, or at least grow very slowly.

The difference is between canning and curing, not between fish and meat. It's also possible to can meat (in which case it doesn't need preservatives) and cure fish (for example, smoked salmon).

  • 7
    Since this question hit HNQ and we have many users who misunderstand basic food preservation anyway, I took the liberty of expanding a sentence to point out that it has been boiled under controlled circumstances. There are too many people out there who think that reaching boiling kills all bacteria instantly.
    – rumtscho
    Apr 28, 2019 at 7:49
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    And too many people who don't know that sometimes bacteria aren't the real problem, and that killing the bacteria doesn't even begin to remove the toxins that were produced before you kill them.
    – user57361
    Apr 29, 2019 at 19:54

Canned salmon is sterilized. Sterilization uses heat to render a product safe. Cured hams are preserved with salt, and nitrites in some cases. Some hams are also cooked. Furthermore, some fish is salted and dried for curing purposes. Salt and drying greatly reduce water activity to render a product safe. Two different processes, both create a safe product.

  • 6
    The OP asks why preservatives are needed in one case and not in the others. Could the pasteurization technique used for salmon be applied to ham? Could salmon be cured with salt and nitrites? Apr 27, 2019 at 15:39
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    @WaterMolecule: while it couldn't be applied to ham per se, as ham is by definition pork cured with salt, however you certainly could preserve pork via canning. Likewise salmon can be cured with salt, and for a long time prior to canning, fish was regularly preserved in that manner. Apr 27, 2019 at 18:49
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    @WaterMolecule cured fish (including salt curing) is very common see en.wikipedia.org/wiki/Cured_fish .
    – user20637
    Apr 27, 2019 at 18:59
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    Ham is not, by definition, pork cured with salt; ham is, by definition, pork from the hindquarters and/or hindlegs. It's perfectly possible to have uncured ham, possibly preserved via canning. (For that matter, it's also perfectly possible to can cured ham.)
    – Vikki
    Apr 27, 2019 at 21:22
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    @WaterMolecule sure, there exists such a thing as canned stewed meat. Pork, beef or both. It's not popular nowadays because, frankly speaking, isn't very appetizing. But it was ubiquitous in the USSR. No preservatives, just high temperature sterilization.
    – IMil
    Apr 28, 2019 at 8:07

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