ARS | Publication request: INHIBITORY ACTIVITY OF 2-NITROPROPANOL AGAINST SELECT FOODBORNE PATHOGENS IN VITRO

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 29, 2004
Publication Date: November 1, 2004
Citation: Jung, Y., Anderson, R.C., Callaway, T.R., Edrington, T.S., Genovese, K.J., Harvey, R.B., Poole, T.L., Nisbet, D.J. 2004. Inhibitory activity of 2-nitropropanol against select foodborne pathogens in vitro. Letters in Applied Microbiology. 39:471-476.

Interpretive Summary: This laboratory has discovered that a chemical, 2-nitropropanol, has the ability to kill various disease-causing bacteria. The killing activity of this chemical was tested under different conditions against the important foodborne pathogens Salmonella, E. coli O157:H7 and Listeria. Results from our studies showed that when included in the growth medium, 2-nitropropanol killed these bacteria within 24 hours. For instance, more than 99 % of Salmonella were killed by this chemical when tested in an environment that simulates the inside of an animal's gut. Results presented here suggest that this chemical could potentially be developed into a useful antimicrobial supplement to be used to prevent infection of animals by foodborne pathogens that threaten human health. Ultimately, this research will benefit American consumers by helping farmers and ranchers produce a safer product.

Technical Abstract: The aim of this study was to determine the bactericidal effect of 2-nitropropanol (2NPOH) on Salmonella Typhimurium, E. coli O157:H7, Enterococcus faecalis, and Listeria innocua in vitro. Specific growth rates (h-1) of E. coli O157:H7, Salm. Typhimurium, L. innocua, and Ent. faecalis were determined during culture in tryptic soy broth (TSB) supplemented with 0 to 10 mM 2NPOH. The growth of all tested cultures was completely inhibited at 10 mM. Further studies with Salmonella revealed that the rate of growth inactivation in TSB was more rapid (P < 0.05) under aerobic rather than anaerobic culture conditions. Additionally, the augmentation of the bactericidal effect of 2.5 mM 2NPOH against Salmonella was observed at pH 5.6 but not pH 7.0 and 8.2; however, complete bactericidal activity against Salmonella (> 5 log10 reductions) was observed at 10 mM 2NPOH regardless of pH. Salmonella populations were reduced (P < 0.05) more than 2 log units when incubated for 24 h with mixed populations of gut anaerobes in buffered ruminal and fecal fluid (pH 6.8) that had been supplemented with 10 mM 2NPOH compared to populations in control cultures. 2NPOH exhibited bactericidal activity against Salmonella, E. coli O157:H7, L. innocua, and Ent. faecalis. This activity was greater under aerobic and acidic conditions against Salmonella in vitro. Results presented here suggest that 2NPOH could potentially be a useful antimicrobial supplement.