While cottage industry regs allow the sale of low risk foods like dehydrated items, jam, baked goods etc....at farmers markets (directly to the consumer), there's a big change in what is required once you move to wholesaling and selling online. The difference seems to be selling directly to the consumer, where they can ask questions of you face to face as opposed to putting your product on a shelf in a store or selling online.
In most states, it's the dept of agriculture that oversees processors, not your local health district that inspects restaurants. From past experience and a lot of online stories, the local health inspectors don't know squat about food processing. Dehydrating and selling dry mixes is considered food processing like making and selling hot sauces.
Each state has slightly different regs, but most have pretty good inline information. Start by researching "food processing" through the dept of AG, read up on it and then contact them. They have regional inspectors and just having a conversation with the inspector for your area will probably tell you 99% of what is needed to become a licensed processor.
After that, remember insurance, proper business licensing (don't need a corporation or even an LLC to start...),
and when the inspector tells you you need a commercial kitchen....don't panic! There are a TON of commercial kitchen options available if you think outside the box. A restaurant after hours, community center, shared use incubator kitchen, Grange/Elks/Masonic/VFW lodges, church, firehall....anything that has a kitchen could be an option.
Good Luck with your Venture!
Keep us posted, we're here to help~