Getting the Most Out of Preservative Efficacy Testing

Getting the Most from Preservative Efficacy Testing

Since the USP <51> antimicrobial effectiveness test and other preservative efficacy tests are so important, we have assembled some information below that we hope will help formulators, risk managers, and project leaders choose the best possible preservative testing scheme for their situation and product.

Most of our preservative challenge testing customers fit into one of three groups:

Group 1: "I need preservative efficacy data on file, and sure hope it works!"

If you have a product on the market and you haven't yet done a preservative efficacy test, you're not alone. However, Antimicrobial Test Laboratories advises you to schedule one ASAP.

In the United States, consumer products are expected by the FDA to be free from microbial contaminants, and also to withstand microbial attack within the use period of the product. If you are interested in reading more about FDA's regulatory authority with respect to cosmetics, click here. If your product is a soap, it may not fall under FDA regulation. Rather, it may be subject to regulation by the Consumer Product Safety Commission.

Cosmetic product or soap, or "other," preservative efficacy testing is a must! Growth of microorganisms within a consumer product is a very real concern when the product is aqueous in nature.

Take liquid hand soap as an example. It consists mostly of of water along with a good helping of biodegradable surfactants. Our natural inclination is to think "It's soap! It's naturally antimicrobial!" Actually, the opposite is true. Think for a moment about the term "biodegradable." Biodegradable means the chemical can be broken down (eaten) by microorganisms. Thus, anything that's biodegradable is germ food! Throw in some water and a comfortable pH (about 4 - 9) and microbes are sure to grow.

If you are in the process of formulating, manufacturers of preservative chemicals can be a great resource. They are normally happy to send information about their preservatives in the hope that you will choose their chemical to help keep your product microbe-free.

Most people who formulate consumer products know about the risks associated with microbial contamination either during or after manufacture, so they choose to run microbiological studies to verify that their products are preserved as expected. By far, the most common method used to benchmark preservative efficacy is the USP <51> antimicrobial effectiveness test. Just click on the link, and you will find plenty of information about this method.

Antimicrobial Test Laboratories starts USP 51 tests every Wednesday. If you need to get some data on file pertaining to preservative efficacy, just Contact the Laboratory however is easiest for you. You'll find that setting up USP 51 studies with us is quick, simple, and reasonably priced.

Never done a preservative challenge test on your product and scared it won't pass? Don't worry! If you're in an extreme pH range or are using a known preservative at the manufacturer recommended level, chances are that your product will fare well.

Group 2: "My product was dirty, and I must prevent future contamination."

Formulators who have been in the game for a while know that USP 51 tests don't always predict preservative efficacy once the inevitable "wild card" is thrown into play - manufacturing.

Many companies blend and manufacture liquid consumer products. The vast majority of these companies are knowledgeable about microbial contamination of the manufacturing environment and go to great lengths to reduce the number of microorganisms introduced into a product during manufacturing.

No matter how hard one may try, the manufacture of liquid consumer products like soaps, lotions, and shampoos is far from sterile. Worse, the manufacturing environment often houses contaminants different from those used for USP 51 testing. Most of the time, problematic contaminants are water-adapted microbes bearing intrinsic resistance to antimicrobial agents.

So your product was contaminated - how do you resolve the issue? Antimicrobial Test Laboratories recommends isolating the problematic microbe, identifying it, and then using it as a challenge organism for any future products to be manufactured in that facility.

Group 3: "I am optimizing a formula. I need some preservative screening done on a large number of samples."

People in Group 3, Antimicrobial Test Laboratories loves you! Every preservative screening endeavor is a bit different, though, so we encourage you to call us so we can together work to find the best preservative screening option. We want what you want - to set up a screen that will be fast, cost-effective, and accurate.

Antimicrobial Test Laboratories has a great deal of expertise in preservative efficacy testing, and in particular the USP <51> challenge test. Whether you're optimizing a formula, fixing a microbial contamination issue, or simply getting some preservative efficacy data on file, we can help.

For more information about preservative effectiveness testing, or to set up a study, Contact the Lab Today!