New treats include quiet spray (7)
I believe the answer is:
spatter
'spray' is the definition.
(thesaurus)
'new treats include quiet' is the wordplay.
'new' is an anagram indicator.
'include' is an insertion indicator.
'quiet' becomes 'p' (music symbol for 'piano').
'treats' with letters rearranged gives 'satter'.
'satter' enclosing 'p' is 'SPATTER'.
(Other definitions for spatter that I've seen before include "Set part (anag.)" , "spray" , "shower" , "Cover with droplets" , "Sprinkle" .)