Posted: 10/06/2016 at 22:49
If the leaves taste OK, then keep using them. Once they get a bit past it, they can become tough and bitter, and often peppered with insect holes, but if they seem appetising, you can eat them .
But yes, you do need to sow some more. So do I, thanks for the reminder!
I should add: the above applies to the plants bolting. If it's the spray you're worried about, read the bottle. Some things barely taint the crop, others make it unusable for a week or two.