Food Corps are for C3's?

So, I built a Butter company thinking that it might be a good money maker, and I thought it would be a nice way to round out my industry mix in the country, having opened all industrial and mining companies so far.(Perhaps using fewer high tech workers and more regular workers, even when upgraded)

Turns out, it's not such a great business, at least not run in the way I've been running my other state businesses. I did some basic 'looking into it' things, and the primary problem, as far as I saw, was the cost of the materials. Turns out Milk may be a better business than Butter.

I thought, well maybe if I open a good 'value-priced' milk company, I can support the butter business, and not have to destroy a great new corp. (Having only other agri/food corps as a 'change output' choice). Then I saw that milk corps need a lot of expensive cattle feed. I'm not sure building 2 more corps to s

Build corps with products that are in the red. Industrial, mining, and high tech corps are prime candidates whereas food corps generally aren't.

Thanks for the response.

Also, is there any way to stop corps from closing, I've had two highly upgraded corps ,producing good industrial and mining goods, just close during a downturn in the market, in a matter of months, when I missed a turn or two..thats a lot of investment to just loose????