I pressed apple cider last year and added nothing.... I just left it in 15 liter jugs covered with cheese cloth and paper towel... it smells like alcoholic cider, tastes pretty good, and is dark rich color.... is it safe ?
The human senses are actually very fine tuned to alert you to the presence of bacteria and mold and prevent botulism (though I think you probably understand this implicitly and just want an authoritative answer).
Firstly, look at your brew. Infection will typically manifest as black spots or a layer of pellicle on the top of the drink. Second, smell it -- any off-putting smells will alert you to any infection. Finally, taste it -- if your cider tastes pretty good, this is a good indication that your brew is coming along well. Your cider should taste clean almost like the wine from the store (which is sometimes considered a compliment to homebrewers).
One of the things I have found helpful in determining quality is the addition of pectinase (pectin enzyme) as this allows the cider to be crystal clear by dissolving the fruit pectin's (that cause cloudy-ness) into sugar. This is the best way to quickly troubleshoot if a brew is safe (as simply not being clear will alert you to issues) and in addition, will help convince anyone you give your homebrew to that it is, indeed, safe to drink. Keep in mind pectinase takes some time to work, and you need your yeast to fall out of suspension (when it all goes to the bottom as a layer of sediment) before you can check it in such a manner.
With the addition of pectinase, my cider actually turns out even more clear and translucent than when I buy the juice fresh from the store, which I find to be more visually appealing than the hazy version you get without it.
Extra note: I noticed you did lambics but you seem pretty new to homebrewing. Please note that you need to store your cider in an airtight container when you are finished fermenting to prevent yourself from ending up with apple cider vinegar.