Trial Number 46

Three substrates, stainless steel, plastic and glass, were selected to represent possible materials that would be cleaned in a dishwasher. Three cleaning products were tested and compared to each other and to water. Each product was added to the Maytag home dishwasher so that the dispenser was half full. Each substrate was contaminated with a 50:50 mix of Hucker's soil and SSL’s kitchen soil using a hand held swab and allowed to sit for 24 hours. A second set of weights were recorded to determine the amount of soil added to each coupon. In addition to the coated coupons, three uncontaminated coupons were included in the washing cycle as a way to determine re-deposition of the contaminant onto the surface of the coupons. The cleaning cycle operated at 160 F and run for hour and half. At the end of the cleaning/ rinsing/ drying, the coupons were removed from the unit, final weights were recorded and efficiencies calculated.

Two of the products were successful in removing the hucker-kitchen soil mix from the three substrates. When tested with water alone, only 60% of the soil was removed. In addition, the plastic coupons, when washed with water alone came out looking grey and were coated on both sides with a thin layer of the soil mix. The table lists the amount of soil added, the amount remaining, the efficiency for each coupon cleaned and the average removal from each substrate type.

Blank samples weight changes were measured using a unsoiled coupon cleaned along with the contaminated coupons. Only the plastic coupons had an noticeable increase in weights. The weight change and percent change are listed in the table below.

Cascade and DFC GPC Polish removed over 85% of the soil mix using spray washing and did not resoil the coupons during the washing process. Water alone resulted in the plastic coupons becoming resoiled.