清委會 消委會指出，部分不銹鋼煮食用具的產品說明上，會顯示3位數字，如200、300及400等，反映不銹鋼中鉻、鎳及錳的大約含量。當中以304、18/8及18/10的耐腐蝕程度較佳，意思是含有18%鉻和8%鎳，或18%鉻和10%鎳。 比較 Many producers also added copper to their alloys to reduce the very high rate of cold working. Often these low chromium alloys are not standardized and are banned for food contact use in China. In the food industry, often the most corrosive conditions are not the food, but the sanitising chemicals used. The 300 series alloys are approved, standardized, and are the food contact materials of choice around the world. Reference Nickelinstitute Seriouseats Which Erin Brockovich Types of stainless steel Test kit eg this one 麗達五金電熱using together with 9V battery 304/316 chemical seems to be molybdenum spot test, or potassium thiocyanate . Google patent , YouTube Simple magnet test YouTube AZOM various test methods