P3-62 Comparison of Commercial Sanitizer Monitoring Strips

Wednesday, July 12, 2017
Exhibit Hall (Tampa Convention Center)
Tiah Ghostlaw , University of Massachusetts-Amherst , Amherst , MA
Amanda Chang , University of Massachusetts-Amherst , Amherst , MA
Paola Martinez-Ramos , University of Massachusetts-Amherst , Amherst , MA
Amanda Kinchla , University of Massachusetts-Amherst , Amherst , MA
Introduction:  The FSMA Produce rule requires that all agricultural water remains free of pathogens, recommending sanitizer use to ensure this. There is currently limited guidance on the validation of appropriate tools that can help to monitor produce sanitizer for small scale farm operations.

Purpose:  This study investigated different peracetic acid and hydrogen peroxide strips available on the market and evaluated which test strips are the most accurate against traditional titration methods.

Methods:  This experiment evaluated the effect of organic load capacities (0, 100, and 500 COD) at different PAA concentrations (0, 30, 60, and 80 ppm). Titrations were performed with ceric sulfate and sodium thiosulfate to validate the amount of PAA and hydrogen peroxide in each sample. Following titration, test strips were tested according to the manufacturers’ instructions and compared to the titration method for accuracy. Experiments were conducted in triplicate with three test strips per trial (n=3) and reported values were statically analyzed using a T-test on SAS program.

Results:  Of the test strips used, three brands tested peroxide levels, and six tested PAA levels. With 0 COD, 33% of the peroxide strips and 25% of the PAA strips accurately reported the peroxide levels. With 100 COD, 25% of the peroxide strips and 17% of the PAA strips accurately reported the results. With 500 COD, 8% of the peroxide strips and 17% of the PAA strips accurately reported results.

Significance:  This work is significant to the produce industry because it demonstrates that commercial PAA test strips are not able to accurately report sanitizer concentration levels and are negatively affected by the presence of organic load. Future work is needed to focus on alternative methods to support small growers in verifying sanitizer concentration in postharvest wash waters.