Translation Help Requested… – Sybaritica

Hi Readers… I am hoping someone (friendlytm maybe?) might be able to help me with a bit of a translation difficulty. I am trying to translate a recipe for 紹興醉蝦 (Shaoxing Drunken Shrimp) written in Chinese Characters. The first instruction reads:

I gather this requires one to add scallion and ginger to boiling water, then add the shrimp and bring to the boil again. The next part of the instruction is the four characters you see pictured at the beginning of the post and it is this that is giving me a bit of a problem…

I have an idea that the instruction, presumably referring to the shrimp, is to ‘keep on ice’, or ‘plunge into ice water’ maybe, but I am not completely certain about this. In particular, it is the second character (鎭) that is making things difficult. I can’t locate any compound word formed by the first and second characters ( although I do see them occurring together in other texts), and the usual meanings of the individual character itself don’t seem to work here. Is the whole instruction a Taiwanese idiom, maybe?

Anyway, any confirmation that I am on the right track would be helpful, but a detailed explanation would be even better!

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