The following journal reference is of interest:
Reference: X. Lu, B.A. Rasco, J.M.F. Jabal, D.E. Aston, M. Lin, and M.E. Konkel, 2011. Investigating antibacterial effectxs of garlic (Allium sativum) concentrate and garlic-derived organosulfur compounds on Campylobacter jejuni by using Fourier transform infrared spectroscopy, Raman spectroscopy, and electron microscopy. Appl. Environ. Microbiol. 77:5257-5269.
The folk wisdom that eating garlic fights illness is ancient. In these more modern times, fruit and vegetable extracts that can inhibit the growth of pathogenic and spoilage microorganisms are actually being evaluated as food preservatives, in part because consumers are demanding fewer synthetic chemical food preservatives. Now, a team led by researchers from Washington State University, Pullman, has found, contrary to expectations, that a group of garlic-derived organosulfur compounds has greater antimicrobial activity than garlic-derived phenolic compounds. The research is published in the August 2011 issue of the journal Applied and Environmental Microbiology.
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