Prudent having American medical facility in food processing plant (7)
I believe the answer is:
cannery
'food processing plant' is the definition.
(place where food is canned)
'prudent having american medical facility' is the wordplay.
'prudent' becomes 'canny' (I've seen this in another clue).
'having' indicates putting letters inside.
'american medical facility' becomes 'er' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'canny' going around 'er' is 'CANNERY'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for cannery that I've seen before include "Food container factory" , "Row in Monterey" , "Factory filling tins" .)