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Title: Antimicrobial effect of acidified sodium chlorite, sodium chlorite, sodium hypochlorite, and citric acid on Escherichia coli O157:H7 and natural microflora of fresh-cut cilantro

Author
item ALLENDE, ANA - CEBAS-CSIC, MURCIA, SPAIN
item McEvoy, James
item TAO, YANG - UNIV MD, COLLEGE PK, MD
item Luo, Yaguang - Sunny

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2008
Publication Date: 11/14/2008
Citation: Allende, A., Mcevoy, J.L., Tao, Y., Luo, Y. 2008. Antimicrobial effect of acidified sodium chlorite, sodium chlorite, sodium hypochlorite, and citric acid on Escherichia coli O157:H7 and natural microflora of fresh-cut cilantro. Food Control. 20:230-234.

Interpretive Summary: There is an industry need for improved sanitizers that are more effective at eliminating microbes, including human pathogens, from fresh-cut fruits and vegetables. Cilantro is a culinary herb that has been repeatedly associated with harboring human bacterial pathogens. In this study, various concentrations of acidified sodium chlorite (commercially known as SANOVA) were tested as a sanitizer on freshly cut and intact cilantro. Their effectiveness in removing human pathogenic bacteria and fungi were compared to the effectiveness of a more commonly used chlorine sanitizer, sodium hypochlorite. Acidified sodium chlorite at low concentrations was just as effective at killing bacteria and fungi as chlorine at the maximum level allowed for commercial use, and better at higher levels. The knowledge that acidified sodium chlorite is more effective than sodium hypochlorite in eliminating a wide range of microorganisms from cilantro will be useful to the fresh produce processing industry in decision making processes concerning sanitizers.

Technical Abstract: Fresh-cut cilantro is particularly susceptible to microbial growth and therefore, use of an effective sanitizer on this product is of great importance. The objective of this study was to evaluate the efficacy of different sanitizing treatments on reducing Escherichia coli O157:H7 populations, total aerobic bacterial count, yeast and mold counts on fresh-cut cilantro. Cut cilantro was treated with sodium hypochlorite (SH) at 0.2 g L-1 free chlorine and acidified sodium chlorite (ASC) at 0.1, 0.25, 0.5 and 1 g L-1, along with the components of ASC, i.e. citric acid (CA) at 6 g L-1 and sodium chlorite (SC) at 1 g L-1. Test results indicate that SH inhibited, at maximum, 1-1.3 log cfu g-1 of background or pathogenic microflora present on cut cilantro. However, reductions of more than 3 log cfu g-1 were observed after washing with 1 g L-1 of ASC. Moreover, when moderate concentrations were used (0.25 and 0.5 g L-1), microbial populations were reduced by about 2 log cfu g-1. CA reduced the total aerobic bacteria and E. coli O157:H7 populations by approximately 1-1.3 log cfu g-1, the same reduction range achieved with SH. SC was as effective as ASC at 1 g L-1 in reducing total aerobic bacteria and E. coli O157:H7 populations, although it was not as effective as ASC in reducing yeast and mold populations.