When sourcing microbiology chemicals, you must prioritize ISO 9001 for quality management and ISO 13485 if the chemicals are used for medical diagnostics. For culture media, ensure compliance with ISO 11133, which governs the preparation and production of culture media. Always request a Certificate of Analysis (CoA) for every batch to verify purity levels, pH balance, and growth promotion capabilities. Additionally, check for REACH compliance if you are exporting to the European market to ensure chemical safety.