Safety

Safety is one of the most important factors when preparing any sort of food. Making yourself sick is bad enough, but making someone else sick is an entirely different matter and can have lifelong consequences. 

With that said, most types of fermentation are generally quite safe, and many have been developed essentially for the purpose of preserving food and preventing spoilage. So, if you do your homework and use some common sense, you should be totally fine.

The following are some generally good rules of thumb.

1) Before you try something, read multiple sources. If they give conflicting information, check more sources and really try to get to the bottom of it. Many of these techniques are thousands of years old but somehow there's still lots of misinformation floating around.

2) Use your senses of smell and sight. If something looks different than you expect, or smells different than you expect, trash it unless you can find an explanation that you are very confident in. And never ingest anything that smells "off," unless that's expected (like with some cheeses!). Finally, if you taste something that you thought was fine but doesn't taste good, don't be afraid to spit it out.

3) Even if you have followed the previous rules, and are confident that what you produced is safe, try it yourself before feeding it to other people!