Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Allicin and Garlic

Name: Vanessa
Status: student
Grade: 9-12
Location: CA
Country: USA
Date: Fall 2011

Hi, I'm doing an experiment that involves the effect garlic extract on the growth of E. coli bacteria in nutrient agar. How should I sterilize that garlic extract if the main anti-bacterial agent within garlic is the unstable compound Allicin?

Dear Vanessa,

One way to sterilize small molecules such as allicin is to pass the extracts through filters that have pore sizes of 0.45 micrometers or less that will trap the bacteria but allow the smaller molecules to pass through. You may want to remove large particulate matter by centrifuging the crude extract and then taking the liquid fraction and filter-sterilizing it.

Your experiment will be interesting.

Good luck,

Jim Tokuhisa, Ph.D.
Assistant Professor
Horticulture Department
Virginia Tech


Basically, Allisin is transiently formed compound during crushing of garlic. Since you cannot boil/ autoclave it, so to my mind is filter it using smaller pore filters manufactured by Millipore. These are bacterial filter that fit with a syringe. I hope that would do the trick.

Waseem S Abbasi

Rather than heat sterilization, consider the use of physical exclusion instead. A syringe and sterilizing grade filter should exclude any biotic contaminants. You may want to do a few pilot runs with different pore sizes to see which does the job most satisfactorily.

Dr. Tim Durham
Instructor, Office of Curriculum and Instruction
University Colloquium
Department of Biological Sciences
Florida Gulf Coast University

Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory