Corn periodically safe to eat and easy to swallow? (8)

I believe the answer is:
credible
'easy to swallow?' is the definition.
(I've seen this before)
'corn periodically safe to eat' is the wordplay.
'periodically' means one should take alternating letters (letters must be selected 'every so often').
'safe to eat' becomes 'edible' (something edible is safe to eat).
The alternating letters of 'corn' are 'cr'.
'cr'+'edible'='CREDIBLE'
'and' acts as a link.
(Other definitions for credible that I've seen before include "Plausible" , "Believable - reliable" , "Seemingly worthy of belief" , "Worth buying" , "Capable of being believed" .)