Preservative 282 is also called calcium propionate. This substance is used as an ingredient in food to slow down the growth of mould and other micro organisms, so as to give food a longer shelf life. It is found in many bread products.
There are regulations that limit to the amount of this preservative that can be added to food, and it is a substance that is well tolerated by most people and generally does not cause health issues.
However, there is some research to show that there are people who cannot tolerate this preservative if they eat too much of it. Reactions can vary, though they may include changes in mood and behavior, and digestive, skin and respiratory problems.
If you are certain you are adversely affected by eating food with Preservative 282, you need to look closely at the ingredient list of foods, and avoid foods that contain it as an ingredient. It will often be listed in the ingredients as either preservative 282 or calcium propionate.