Sulfites are a commonly used preservative found in foods, alcoholic drinks (especially wines), and even in medications. They are anti-oxidants that are often used in salad bars to prevent the lettuce from browning and on dried fruits to prevent them from becoming very dry and stiff.

So do we use Sulfites in our egg cures to help keep the eggs fresher for a longer period in the fridge or is it a chemical that actually helps turn on the bite with Salmon?

I have heard that we use it for both reasons. A tip of the hat to the nitrates and nitrites. Curing agents that also contribute to development of color and flavor; and propylene glycol to keep the mixture uniform