JOURNAL OF COSMETIC SCIENCE 98 95% confi dence) as their score differences (including confi dence limits) were not greater than the non-inferiority margin of 0.4. Because the mean erythema scores for the fabrics washed with any detergent product were less than 0.3 units different (on a 4-point scale) from the fabric washed with water, all of the fabrics washed with the detergent products tested can be considered mild. Figure 4. Forear m skin surface pH measurements after each of the four exposures to the test materials in the 1-d RIFT study. Table I Upper Ar m Erythema Scores (21 D) with 95% Confi dence Limits from the 21DCIT Treatment Mean skin score Lower confi dence limit 95 Upper confi dence limit 95 Distilled watera 1.60 1.41 1.78 Fabricb washed in water 0.94 0.76 1.13 Fabricb washed in TFG liquid detergent 1.11 0.93 1.29 Fabricb washed in AFC liquid detergent 1.08 0.90 1.26 Fabricb washed in TPFG laundry pac 1.21 1.02 1.39 Fabricb washed in AFCMP laundry pac 1.07 0.89 1.25 0.05% SLSa 1.95 1.77 2.14 a For the control materials, 0.3 mL was applied directly to the patch. b Fabrics are 2 × 2 cm2 of 100% cotton T-shirt washed three times in a HE washing machine with the indi- cated treatment.

MILDNESS OF LAUNDRY DETERGENTS DIFFERING IN pH 99 pH VALUES AND RESERVE ALKALINITY The unadjusted pH values of the RIFT solutions are shown in Table II. The 4,200 mg/kg solution of AFC had a pH value of 9.81, substantially higher than the pH 7.03 value for the 4,200 mg/kg TFG solution and similar to the pH value of the 4,200 mg/kg AW solu- tion (pH 10.61). Additional pH measurements were made on the neat liquid detergent formulations and their solutions (Table III). The neat AFC formulation had a substantially higher pH (10.8) than that of the TFG formulation (7.9). Solutions (10%) of the same detergents showed similar differences in pH. Consistent with those observations, AFC was shown to have a higher reserve alkalinity value than TFG (1.55 vs. 0.81). The pH values for the washed cotton fabric are shown in Table IV. The water-washed and AFC-washed samples yielded pH values near 9 and were not signifi cantly different (p 0.05) from each other. However, the TFG-washed cotton fabric yielded a pH of 8.26, which is signifi cantly lower than the pH of either the water-washed fabric (p = 0.0024) or AFC-washed fabric (p = 0.0011). DISCUSSION Skin can be directly exposed to commercial laundry detergents, e.g., during hand-laundering of fabrics or during hand prewashing or pretreating (e.g., applying liquid detergent to shirt collars or to visible stains) before the use of a commercial washing machine for full wash. Recent research has found that a signifi cant number of U.S. consumers wash at least some laundry loads by hand (unpublished P&G 2015 USA Habits and Practices Survey). For the survey, an Internet research supplier recruited 3,175 consumers nationwide (70% females, 30% males) who were over the age of 18 years and responsible for doing their household laundry and laundry product purchasing. The consumers replied to questions presented to them via an Internet survey. Their responses revealed that 20% of them do at least some loads of laundry by hand, indicating that there is substantial exposure of the skin to dilutions of liquid laundry detergents. The same survey shows that among people who do laundry by hand, 5% hand-wash daily, 14% hand-wash two to three times per week, and 20% hand-wash weekly. It takes approximately 5 min to hand-wash a garment. So, if we Ta ble II Treatment Solutions in the Repeat Insult Forearm Test (RIFT) Study Treatment solution (see Materials and Methods for details) Water hardness (CaCl2/MgCl2) pH of test solutionsa Water (negative control) 0 6.48 0.5% SLS 16 7.08 1% SLS 16 6.86 4,200 mg/kgb TFG 7 7.03 4,200 mg/kgb AFC 7 9.81 4,200 mg/kgb AW 16 10.61 a No pH adjustments were carried out in preparing these test solutions. b Solutions of 4,200 mg/kg TFG, AFC, and AW (equivalent to one manufacturer-recommended dose of liquid detergent in 5 gallons of water) were chosen as reasonable doses of detergent for hand-washing of laundry.