Sulphites are used in many foods for different functions:

 

  • anti oxidants (action on color, preservation)
  • antiseptics (kill bacteria, yeasts)

    Sulfites can be natural ( certain yeast can generate sulfites ) or added 

1) IN WINE:

 

the regulation of wines imposes the following limits :

 

 example of french regulation :

 

 wine type  mg/l
red 160
dry white and rosé 210
sparkling  210
 sweet wines  400


 

 

Some producers  are obliged to put large doses of SO2 to prevent their wines from fermenting in the bottle or from bacteria to develop deviant tastes (acetic or lactic sting).
In particular sweet wines containing sugar, a source of energy for yeasts, are likely to restart fermentation.

This is what is used in champagne to produce carbon dioxide ( 2nd alcoholic fermentation is caused by the addition of liquor ) .

 

The necessary sulphite dose is all the stronger as the acidity of the wine is low (thus high pH).

 

2) IN FOOD:

see the excellent article by Bertrand Waterman that summarizes the situation: https://les-sulfites.com/danger-ils-sont-partout/ ( with the help of google translate )

 

 

 

The best  solution to avoid potential problems:  check yourself the rate of sulphites