Dirty dozen (worst first):

Peaches

Apples

Bell Peppers

Celery

Nectarines

Strawberries

Cherries

Kale

Lettuce

Grapes (Imported)

Carrots

Pears

Clean 15 (best first):

Onion

Avocado

Sweet Corn

Pineapple

Mango

Asparagus

Sweet Peas

Kiwi

Cabbage

Eggplant

Papaya

Watermelon

Broccoli

Sweet Potato