Not a stupid question at all. In fact, identifying the real hazard from any chemical in the working environment (and foods are chemicals, after all) is one of the most complicated challenges when considering the risk assessment required for COSHH. There are literally thousands of chemicals that will never appear on a safety data sheet but that, under certain conditions, can represent a hazard to health. This is covered in the COSHH regulations: “(e) which, not being a substance falling within sub-paragraphs (a) to (d), because of its chemical or toxicological properties and the way it is used or is present at the workplace creates a risk to health” - COSHH Regulation 2 (1) Interpretation This is such a complex (and for some contentious) topic that I would not try to cover it directly on the forum. If you wish feel free to PM me with your contact details and I will send you an article I wrote on this for the BOHS. Chris