Questions about testing your lotions for nasties

[cerelife]

I began making lotion last fall and my starting off point was this:
http://swiftcraftymonkey.blogspot.com/2009/03/lotions-basic-recipe.html
I tweaked the recipe guidelines using oils that I prefer and using Optiphen Plus as my preservative and created a lotion recipe that I love and can consistently reproduce using different fragrances.
But is it safe and 'yuck' free? That was my next question.
I purchased the LotionCrafter testing kit to test my lotions after reading this entry:
http://swiftcraftymonkey.blogspot.com/2013/03/question-for-you-what-do-you-think.html
I did spot checks on different batches (including my oldest batch from November 2015) and they all came out clean.
However, the face lotion recipe I had just created the week before had some minimal reactions (per the comparison chart on the instructions/website) on both sides of the tester paddle. I'm thinking this may be because I was using several premium oils that I had been hoarding and they may have not been as fresh as they needed to be. They didn't smell rancid, but I had had a few of them for several months...needless to say the entire batch went into the trash as I don't want even minimal reactions!
I would like to hear opinions of whether home testing is acceptable for lotions I intend to sell. I asked a fellow soapmaker at my weekly market (who already sells lotions) and she said she doesn't test hers at all.

 

[cmzaha]

If you really want to know if your preservative system works send a sample out to be challenged tested at a lab. Right now I have a shelf full of sample lotions. Some have failed some have not. When I settle on the lotions I want to keep and sell they will go out for challenge testing. Do remember to read the info on your emulsifiers to find out what is compatible. I have one emulsifier that I cannot use EDTA in per the manufacturer of the emulsifier. I came up with using Germall Plus and Optiphen in several of my lotion samples because they can be used together with the emulsifier in those particular lotions. You need to read what is recommended for the emulsifier

My venturing into lotion has become as obsessive as soap making and trying to come up with what meets my criteria has become a challenge. BTW the lotion I have been selling for 7 yrs was challenged tested. One thing I do at my markets in the summer is keep a check on temperatures of the lotions I set out, especially if the sun gets to them. I actually threw away of 20 bottles a few years ago when the heat liquefied the lotions. I was to afraid it destroyed the preservative and would have cost more to have it tested. Just does not take long for a bottle to heat up over 122º F which is the threshold for my preservative

 

[cerelife]

Thanks for the info!
Who do you use for challenge testing (if you don't mind my asking)?
I was thinking of using this one:
http://www.sagescript.com/microbiology