Classification of imported fishmeal

At present, imported fishmeal on the market are SD and FAQ, SD is divided into super steam, Taiwan grade, Japanese grade, ordinary steam, crude goods. Could you tell me how to judge each grade? What is the standard? What is the order of quality? -- there is no good way. Look at the indicators. Fish meal is so difficult to control. Indicators can be falsified and done perfectly. I think the most important thing is microscopic examination. But basically nothing without other things, not much meat, really headache ah, please experts to give some experience, thank you-- I would also like to hear the details of the experts