When we take a closer look at sulfur molecules and sulfite ions (SO2, H2SO3), we see that sulfur was already used in Roman times to preserve wine.
We also learn that there are natural sulfites in fermented foods. The air we breathe also contains sulphite ions (SO2, H2SO3) among the pollutions
The sulfite ions (SO3 and 2) possess antioxidant properties. For this reason, they are frequently used in food as preservatives.
You can identify these preservatives on food labels by their numbers from 220 to 228
preceded by the letter "E," as is the case for other additives.
They must be mandatorily mentioned in it as soon as their concentration exceeds 10 mg
The E220, sulfur dioxide reinforces the flavor, whitens and stabilizes. It is found in hamburger meat, beers, ciders and perries, but also in confectionery, jams, candied fruits, jellies, dried apricots... Sodium sulphite (E221) is one of its derivatives used in particular for the bleaching of salted cod fillets It is an antimicrobial and an antioxidant.
E222, a preservative and bleaching agent, seems to be present in almost all white, red, rosé wines or champagnes at varying concentrations. Also present in some beers, ciders and meads, sodium acid sulphite can cause irritation of the digestive tract and vitamin B12 avitaminosis.
In this family of preservatives, there are also sodium disulfite (E223) and potassium disulfite (E224). E225, calcium disulfite is also known as calcium pyrosulfite or calcium metabisulfite. As for E226, it is calcium sulfite.
Calcium acid sulfite or calcium bisulfite, E227 is a thickening agent and prevents fermentation.
E228 or potassium acid sulfite is found in hamburgers, dehydrated potatoes, dried fruit, confectionery, beer and wine.
Like all synthetic molecules, chemical sulfites can give rise to intolerances with varying symptoms and intensity. They can trigger sneezing, runny nose, itching, hives and headaches. In the most serious cases, this can lead to bronchial irritation, asthma attacks, and even respiratory insufficiency, which is fortunately usually temporary.
Caution should be exercised in asthmatics
And as in all cases of allergy or intolerance, it is often very difficult to establish the link between the somatic manifestation (reaction) and the triggering substance (allergen). Indeed, the time between the allergic or intolerance reaction can vary from a few minutes (migraines, urticaria, asthma...) to a few days (migraines, intestinal or digestive problems). Identifying the allergen is therefore sometimes very difficult. This is a very long process, because it is necessary to analyze methodically each food that we swallow...
The reactions are not always immediate and in the long term, these additives or their accumulation can have much more insidious effects.
It is known that sulfites counteract vitamin B1 binding, increase calcium depletion, and some researchers even go so far as to make them responsible for some DNA damage.
Despite this danger, they are still allowed in many foods with limited maximum quantities.
Here are some maximum allowable concentrations:
- Dried fruits 1000 mg/kg
- Candied fruit 60 mg/kg
- Shrimp 100 mg/kg
- Flaked potatoes 100 mg/kg
- White and rosé wines 210 mg/L
- Ciders 200 mg/L
- Red wines 160 mg/L
- Lemon juice (not fresh) 100 mg/L
In summary
They are used in all categories of foodstuffs and extend their shelf life. They can be found in herbs, pickles, ketchup, mustard, vinegars or salad dressings, jams, canned, candied, dried, juiced, salted or syruped fruits and vegetables, as well as in cereals, cold cuts, fish and shellfish. Or in all forms of potatoes, cookies, breads, cakes, soups, etc.
For information, in France, since November 25, 2005, European Union legislation requires the statement "Contains sulfites" for most wines. Therefore, it is mandatory for labels to indicate the presence of sulfites if the content exceeds 10 milligrams per liter or per kilogram. The few bottles that don't have this label have an extremely low sulfur content.