How to distinguish whether the Australian fetal bovine serum mentioned by the merchant is mixed with South American serum?

Let's not start with physicochemical indicators; instead, look at the documents first: Australian fetal bovine serum should be able to provide a certificate of origin, import customs declaration, original manufacturer's batch Certificate of Analysis (CoA), and health certificate. Focus on checking whether the production address, country, and product number on the CoA match the bottle label, then log in to the original manufacturer's official website to verify the batch. Many adulterations occur at the distributor stage. It is more credible if the country of origin column on the customs declaration states Australia; if only domestic cold storage repackaging records can be provided and there is no certificate of origin, be cautious. If the price is nearly a thousand yuan lower than the market and the lead time is short, the document chain is usually the easiest place to reveal problems.

Australian and South American serum overlaps in routine biochemistry, so it cannot be characterized solely by one or two indicators such as total protein or endotoxin. You can send the suspected batch and the previous batch of Australian serum for testing of hemoglobin, total protein, IgG, and endotoxin at the same time, and conduct a round of comparison, paying particular attention to whether endotoxin and hemoglobin are significantly elevated; at the same time, use HeLa and 293T for parallel culture, comparing doubling time, transfection efficiency, and cell morphology. Adulteration with South American serum often manifests as large fluctuations in transfection efficiency between batches and slightly poorer cell condition, but this is not absolute evidence and can only serve as supporting evidence.

It is advisable to clarify the actual delivery lead time for this batch and the distributor's authorization source. Australian serum typically has a certain lead time from the original manufacturer to domestic delivery; a suddenly short lead time and a price noticeably lower than market may indicate it is not normal original-product circulation. After receiving the goods, do not put everything into inventory at once. Keep the outer box, bottle labels, and one unopened bottle as a retained sample, and photograph and record the lot number; if cell problems occur later, this will be the basis for claims and replacements. You may also require the supplier to provide batch traceability documentation, such as the manufacturer's shipment order or cold-chain transport records. For large-volume purchases, I would first take 1–2 bottles for small-batch functional validation before deciding whether to use them in formal experiments.

Check the COA for the country of origin and the blood source certificate, then verify the batch number. There are too many products falsely labeled as South American.

I got ripped off before, so now I just ask the agent directly for the certificate of origin and customs clearance documents.