These are used to bleach products such as flour.

If you have had the appropriate tests for allergies or reactions to food additives you can find the corresponding numbers that are shown on the packaging to the names of the additives you have a problem with.

Also if you have been asked by your doctor to keep a diary of the foods you eat to find the cause to an allergic reaction you may refer to this chart for the names of the additives.

Or if you just simply wish to be aware of what you are eating you can refer to this chart.