Study to Evaluate the Efficacy of “Sterile-Gel & Spray” by Sterilize Technologies


The objective of this study is to perform a challenge study to evaluate the efficacy of hand & surface Sterilizer(Sterile-Gel & Spray) on Staphylococcus aureus.


In this study, “Sterile-Gel & Spray” was inoculated with a known level of Staphylococcus aureus. Bacteria were then enumerated after a 24 hour hold time.

Organism Preparation

One strain of Staphylococcus aureus(DL58, ATCC #25923) was inoculated into a sterile 100ml Trypticase Soy Broth(TSB Broth) and incubated at 35oc for 24 hours. After the initial 24 hours of incubation, an aliquot of broth culture was transferred to a second sterile 100ml TSB and will incubate at 35oc for 24 hours. The broth culture was serially diluted and plated on Tryptic Soy agar(TSA) at 101 to 108 to determine bacterial density.


The Broth Culture was then diluted to create an inoculum suspension with a bacterial density sufficient to deliver an initial inoculum of 104 to 107 cfu/gram. The inoculum suspension was serially diluted and plated on Tryptic Soy agar(TSA) 101 to 108 to determine initial bacterial density. TSA plates will incubate 35oc for 24 hours. Colonies were counted and recorded.


Staphylococcus aureus initial bacterial load 71,000,000 cfu/mL
Control (TSB) after 24-hours150,000,000 cfu/mL
Sterile-Gel & Spray Sample 1<10 cfu/mL
Sterile-Gel & Spray Sample 2<10 cfu/mL
Sterile-Gel & Spray Sample 3<10 cfu/mL


S. aureus was inoculated into the product with a bacterial density of 71,000,000 cfu/mL and after 24 hours of incubation all bacteria experienced die off when in contact with the test product (“SterileGel & Spray”). All three samples tested had a bacterial load below the detectable limit. A positive control was used with the same initial bacterial load and which showed a final concentration of 150,000,000 cfu/mL. S. aureus is unable to grow in the product and experienced total kill off.

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DonLevy Laboratories

DonLevy Laboratories
Prepared for Sterilize Technologies
April 14, 2020