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Title: THE EFFICACY OF SANITIZERS ON THE REDUCTION OF E. COLI O157:H7 FROM SHREDDED CARROTS UNDER SIMULATED FRESH-CUT PROCESSING CONDITIONS

Author
item GONZALEZ, ROLANDO - UMN
item Luo, Yaguang - Sunny
item RUIZ-CRUZ, SAUL - MEXICO
item McEvoy, James

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2004
Publication Date: 11/15/2004
Citation: Gonzalez, R.J., Luo, Y., Ruiz-Cruz, S., Mcevoy, J.L. 2004. The efficacy of sanitizers on the reduction of e. coli o157:h7 from shredded carrots under simulated fresh-cut processing conditions. Journal of Food Protection. 67(11):2375-2380.

Interpretive Summary: Fresh-cut produce is one of the hottest growing convenience foods in history. Unfortunately, contamination of these commodities with disease-causing microorganisms can occur anywhere from farm to table. Given that these products are marketed as read-to-eat without further microbial killing steps, the need for effective washing agents is clearly evident. In a common scenario of water re-use in the fresh-cut produce industry, chlorine, a widely used sanitizer in the fresh produce industry, is readily inactivated upon contact with organic matter in the process water. Sanitizers that can maintain the efficacy of pathogen removal under the fresh-cut processing conditions is highly needed. The study was aimed to provide a side-by-side comparison of the efficacy of chlorine and three new sanitizers on pathogen reduction of shredded carrots under simulated commercial processing conditions. Fresh carrot shreds were artificially inoculated with E. coli O157:H7 and washed in various sanitizer solutions, including 200 ppm chlorine, 1% Pro-San®, 80 ppm Tsunami® - 100, and 1,000 ppm SANOVA® under fresh tap water or simulated processing water conditions. We found that SANOVA® (acidified sodium chlorite) provided a strong pathogen killing effect in both tap water as well as process water conditions with more than 99% reduction when compared to a tap water wash. The role of sanitizers in maintaining the microbial safety of wash water was also evaluated, with no recovery of pathogenic E. coli O157:H7 or total bacteria from sanitizer solutions used to disinfect, eliminating the possibility of cross-contamination of other produce and potential quality deterioration.

Technical Abstract: Chlorine is widely used as a sanitizer to maintain the microbial quality and safety of fresh-cut produce; however, chlorine treatment lacks efficacy on pathogen reduction, especially when the fresh-cut processing water contains heavy organic loads. A more efficacious sanitizer that can tolerate the commercial processing conditions is needed to maintain microbial safety of fresh-cut produce. This study evaluated the efficacy of Escherichia coli O157:H7 reduction on fresh-cut carrots using new and traditional sanitizers with tap water and fresh-cut processing water scenarios. Fresh carrot shreds inoculated with E. coli O157:H7 were washed in sanitizer solutions (200 ppm chlorine, 1% Pro-San®, 80 ppm Tsunami® - 100, and 1,000 ppm SANOVA®) prepared in fresh tap water or simulated processing water with a chemical oxygen demand (COD) level of approximately 3,500 mg/L. Samples were packaged and stored at 5°C. Microbial analyses performed at days 0, 7 and 14, indicate that the organic load in the process water significantly affected the efficacy of chlorine on pathogen removal, especially evident on samples tested during storage. SANOVA® provided a strong pathogen reduction even under process water conditions with at least a 3.5 log reduction when compared to a water wash. E. coli O157:H7 was not recovered on SANOVA® treated samples during the entire 14 days storage, even following an enrichment step. These results suggest that SANOVA® holds considerable promise as an alternative sanitizer of fresh-cut produce.