The best way is to search for local foodie bloggers in your area. You will want to give them a sample of some of the healthy snacks that will be a part of the subscription. Twitter is a GREAT way to reach these people. Since you only have 160 characters, you want to make it short and sweet.
Something like:

Hey (name), I would like to send you a sample from my healthy food subscription service. Where should I send it?

More often times than not, you will get a reply and address to send it. I would then include a handwritten note about the service and offer a complimentary 3 month subscription to them. The goal is to offer them a sample, give them a gift and build rapport all at the same time.

Let me know if you have any more questions!