It looks like you're referencing a specific publication from the Food and Agriculture Organization (FAO) regarding fish canning methods and procedures. To properly cite it, you would need to include the URL where the document can be accessed.
Here's a general format for your citation based on what you provided:
Food and Agriculture Organization. (2021). Canning fish: methods and procedures. Retrieved from [URL]
Replace "[URL]" with the actual link to the document. If you provide the URL, I can help format it for you!