Final answer:
Boiled linseed oil is not food safe due to the additives and metallic dryers used to speed up the drying process when it's manufactured for industrial uses. It's distinct from food-safe, raw linseed oil, which is edible and known for its health benefits. Any linseed oil used with food must be explicitly labeled as food safe.
Step-by-step explanation:
Boiled linseed oil is not considered food safe. While linseed oil, also known as flaxseed oil, is a product that can be processed to be edible, the boiled version often contains metallic dryers and other additives to expedite its drying process when used as a finish or wood conditioner. These additives can be toxic if ingested, so it's important to understand that raw and food-grade linseed oil must be explicitly labeled as food safe and not have any of these chemical additives.
In its raw form, linseed oil can be part of a healthful diet and is known for being rich in omega-3 fatty acids. However, when processed into boiled linseed oil for industrial purposes, it undergoes changes that make it unsafe for consumption. Therefore, one should never use boiled linseed oil on any surfaces that will come into contact with food.