Gram-negative and gram-positive bacteria, Escherichia coli (E.coli) ATCC 29214 and Listeria monocytogenes (L. monocytogenes) ATCC 35752, were sub-cultured twenty-four hours in tryptic soy broth (TSB) at 37°C (98.6°F) prior to testing. For each new E-cloth product, four coupons (2" x 1") of a specified substrate were contained in a sterile petri dish to act as the positive control (P+), negative control (N-), Test 1 (T1), and Test 2 (T2) substrates. The substrates tested for each bacteria type included glass, laminate, and stainless steel related to the product use parameters designated by E-cloth. Ten microliters of the bacteria inoculated the P+, T1, and T2 coupons. Coupons were incubated at room temperature for 15 minutes in an aseptic environment before treating the N-, T1, and T2 coupons with an E-cloth product. The P+ coupons were placed into 50ml conical tubes containing Dey and Engley (DE) Neutralizing broth.
Supplied new E-cloth products were dipped in Deionized (DI) water before manually squeezing to keep the product damp before attaching to the sled of the Straight-Line Washability (SLW) unit. The SLW unit simulated manual wiping by passing three times over the contaminated coupon surface before placing the cleaned coupon immediately into each of the respective D/E broth conical tubes with sterile forceps. The conical tubes were placed on the shaker for 10 minutes before performing serial dilutions in 1X PBS up to 104 (1:1000). Stock (1:1) and serial dilution solutions were plated and spread on tryptic soy agar (TSA). Plates were incubated at 37°C overnight. Isolated colonies were counted the following day to calculate log reduction and percent removal for each disinfection test parameter performed.
A majority of the E. cloth products produced a one to two log reduction removal of gram-negative and gram-positive bacteria on the specified glass, laminate, and stainless steel surfaces associated with each product. The Non-scratch Scrubbing Pad was the most effective after a single wipe by removing 100% of L. monocytogenes on laminate. The Kitchen Dynamo performed the best with a three-log reduction of L. monocytogenes after three manual wipes on a laminate surface.