This study evaluated the efficacy of commercially available disinfectant hand sanitizers in the reduction of the bioburden of bacterial hand contamination in twelve (12) volunteer participants. The products tested were: (1.) ethyl alcohol-based hand gel sanitizers, (2.) isopropyl alcohol-based hand gel sanitizers, (3.) water-benzalkonium chloride hand sanitizers, and (4.) 2-propanol-benzalkonium chloride disinfectants, that were all accessible in supermarkets

1. Evaluation of Efficiency of Commercial Hand Sanitizers/Disinfectants in the Philippines
to Reduce Skin Microbial Contamination
Raymond J. Sucgang1,2,3, Esperanza Moya2, Maricar Ching2, Gerna Manatad3,
Plormelinda Olet3, Jayvee Villagracia3, Ralph Lago3
1R.J. Sucgang Center for Research in the Natural Sciences, Napti, Batan, Aklan
2Centro Escolar University, Mendiola, Manila
3MMC-14 Anluwage, Development Academy of the Philippines
Hand sanitation is very crucial in the prevention of the spread of infectious diseases.
Hand sanitizers may help reduce the bioburden of microbes on the skin. Although hand
sanitizers have been shown to be as effective as hand washing in reducing bacterial
load, not all hand sanitizers have the same capability to kill / eradicate the growth of
different microorganisms. This study evaluated the efficacy of commercially available
disinfectant hand sanitizers in the reduction of the bioburden of bacterial hand
contamination in twelve (12) volunteer participants. The products tested were: (1.) ethyl
alcohol-based hand gel sanitizers, (2.) isopropyl alcohol-based hand gel sanitizers, (3.)
water-benzalkonium chloride hand sanitizers, and (4.) 2-propanol-benzalkonium
chloride disinfectants, that were all accessible in supermarkets. Samples were picked
from various retail outlets. Forty-five healthy volunteers participated in the study: 12 for
efficacy and 33 for organoleptic studies. The initial procedure required the evaluators to
systematically wash their hands with soap and water and air drying. This was followed
by contaminating the right and left palms with 5 mL each of homogenized filthy river
water suspension . The left palm was rinsed with 10 mL sterile distilled water and air
dried. The right palm was sanitized with 10 mL of the test disinfectant solution and air
dried. Swabs were taken from the palms of the participants after the procedures. The
swab obtained from the left palm served as control, while the swab taken from the right
palm served as the test sample. The experiment was repeated four more times per
participant, and each repetition used a different test sample until all the four types of
hand sanitizers were tried out. The numbers of viable bacterial microbes present after
application on each palm were used to calculate the efficacy of the hand rub. Efficiency
was calculated by comparing the viable microbial load in the left palm (control) versus
the microbial load in the right palm (test setup). Disinfectants with the ability to reduce
the microbial load by 50% (equivalent to Log reduction below 3) were considered
effective. For the Total Plate Count (TPC) determination, the conventional pour plate
technique as described by ISO Method 4833 was followed. The collected swab samples
were inoculated into 5 ml of nutrient broth in test tubes followed by serial dilution until
10-3 dilution of each sample. A 0.1 ml of the last dilution was poured into sterile Petri
dishes. To each of this broth culture dilution, sterile nutrient agar was dispensed. The
agar was allowed to solidify, after thoroughly mixing the poured solution with the agar.
Total Plate Counts expressed as colony forming units per mL(cfu/ml), were determined
after incubation at 30°C for 72 h. Average TPC was reported per test setup. Results of
the study showed that ethyl alcohol sanitizers reduced the microbial load by 43% while
the isopropyl alcohol sanitizers reduced the microbial load by 35%. The benzalkonium
chloride-based solutions reduced the bacterial load more significantly. Benzalkonium

2. chloride in water sanitizers reduced microbial load to as much as 92% while the
benzalkonium chloride in 2-propanol disinfectant solution completely eliminated the
microbes ( TPC=0). The antimicrobial potency of commercially available hand sanitizers
were revealed in this study. The organoleptic study involved 33 trained evaluators. The
participants were asked to apply one of each kind of the test sanitizers daily on their
hands for ten times per day for a period of 5 days. Rating scales which included
rheology, greasiness, and skin irritability of the test sanitizers were collected at the end
of each week. The hand sanitizer samples were tested one at a time per week using a
randomized block design program. The preference for gel sanitizers instead of the water
based solutions were demonstrated in the results. Alcogels with moisturizers and which
were less greasy were the most preferred hand sanitizers by the respondents.