I'm not certain on these community cookbooks. I would imagine that they are indeed copywritten since they are in printed form. If using them, merely attribute the recipe to where you got it from mentioning the book by name and even the author. I would also recommend maybe suggesting a tweak or two. For example, "I changed this or that or used this product." when using the recipe so that it is more 'your own' version of the recipe than the original. Always attribute the author though and where you stumbled upon the recipe, and I think you should be safe.