None of them, they're all contaminants
Food additives is what substances that are intentionally added to food to produce a desired effect. The additives are used to enhance the taste and appearance and is added to preserve flavor.
Nova Net: Direct Additives
Food additives are substances added to food to preserve flavor or enhance its taste and appearance, for example food acids like vinegar, emulsifiers used in ice cream or homogenised milk etc...
All additives that are listed on the 'ingredients' list are intentionally added.
Additives are put into food to make it taste better, look better and last longer. Sometimes, substances are merely applied topically. For example, ethylene gas is used to change the color of green oranges to orange, and carbon monoxide is used to restore or preserve cut meat's bright red color. Even at home, we put additives into our food, for the same reasons. Salt, sugar and vinegar can be used to help preserve food.
what are alternatives for food additives?
Indirect food additives are substances that are not intentionally added to food but may still come into contact with it during processing, packaging, or storage. They can include materials like packaging chemicals, lubricants, or antimicrobial agents that might leach into food. While not added directly, these substances can affect the safety and quality of food products. Regulatory agencies monitor these additives to ensure they do not pose health risks to consumers.
You might be trying to define 'incidental food additives'. or indirect food additives
Sulfite additives.
you use additives to preserve your food
No, preservatives are used for e.g, keeping food fresh whereas additives are used to enhance the flavour, colour or texture of a food. Of course, you could argue that they are both used to enhance the flavour of a food so I suppose you could put forward an argument saying that they are the same from that perspective.
Flavouring,colouring,bulking agents are some of the food additives.