Background: Hand sanitizers are commonly used as an alternative to washing hands with warm water and soap. There are a variety of different hand sanitizers including gel and foam and they are known to kill several bacteria. Many factors play a role in the effectiveness of hand sanitizers such as the alcohol concentration and the techniques used to apply hand sanitizers. Alcohol based hand sanitizers must have an alcohol concentration of 60 - 70% to be effective. There is currently no legislation regulating hand sanitizers and there is a lack of research focusing on differences between foam and gel hand sanitizers. This research study investigates effectiveness of gel compared to foam hand sanitizers by evaluating the prevalence of Escherichia coli (E.coli) on pigskins.
Methods: To compare the hand sanitizers, microbiological sampling was completed. E.coli was introduced onto 65 pigskins. Five pigskins were used as a baseline to determine the average amount of Colony Forming Units (CFUs) of E.coli present prior to the application of hand sanitizers. One set of the 30 pigskins was applied with gel hand sanitizer, whereas the other 30 was applied with foam hand sanitizer. The pigskins were swabbed with QuickSnap swabs and plated onto 3M Petrifilms. The 65 petrifilms were incubated at 35oC for 48 hours. After incubation, the CFUs of E.coli present on the petrifilm were enumerated. The difference in CFUs was calculated to determine the reduction in E.coli and the overall effectiveness of hand sanitizers.
Results: The data was analyzed by using the statistical software, NCSS. Statistical analysis showed that the findings were statistically significant and the null hypothesis (Ho: no difference in CFUs of E.coli between foam versus gel alcohol-based hand sanitizers) was rejected with a power of 0.9997 at p-value of 0.00000. This indicates that there is a difference in the ability to reduce E.coli between gel and foam hand sanitizers and gel sanitizers appeared to be more effective.
Conclusion: These results indicate that there was a difference in the effectiveness between foam and gel hand sanitizers in reducing E.coli that was inoculated onto pigskins. However, consumers should be aware that hand sanitizers do not completely eliminate all pathogens. Though gel hand sanitizers are more effective, they should only be used when there are no other methods of keeping hands clean., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, E.coli, Escherichia coli, Foam, Gel, Hand Sanitizer, Pigskin, Public health
Background and Purpose: Hand washing is one of the most important critical control points in public
premises in preventing the spread of bacteria and viruses. There is vast research on the effectiveness of
alcohol-based hand sanitizers in killing germs. However, the efficacy of alcohol-free hand sanitizers lacks
real-world evidence. With little to no guidelines in which one type of hand sanitizers may be more
appropriate depending on the types of public premise such as food establishments, hospitals, work place, or
schools, Environmental Health Officers(EHOs)/ Public Health Inspectors(PHIs) will need to educate the
public and operators on the effectiveness of these hand sanitizers and their advantages and disadvantages.
The purpose of the study was to compare the effectiveness of alcohol-based hand sanitizers and alcoholfree
hand sanitizers by conducting statistical analyses of the reduction in mean E.coli counts.
Methods: 60 pigskins were prepared (30 for alcohol-based hand sanitizers, 30 for alcohol-free hand
sanitizers), which were inoculated with E. coli, then applied either alcohol-based hand sanitizers or alcoholfree
hand sanitizers. After 48 hours of incubation for E.coli growth, E.coli was counted. The difference in
mean E.coli counts before applying hand sanitizers and after hand sanitizers was calculated, then compared
between the two hand sanitizers.
The mean E.coli reduction count (CFU) from alcohol-based hand sanitizers (30 samples) was 10.200; the
median was 11; the standard deviation was 1.7889; the range was 5.0000.
The mean E.coli reduction count (CFU) from alcohol-free hand sanitizers (30 samples) was 10.233; the
median was 10.5; the standard deviation was 0.8976; the range was 3.0000.
The statistical t-test resulted in p-value of 0.1034.
Conclusion: There was no significant difference between the two types of hand sanitizers. Both the
alcohol-based hand sanitizers and alcohol-free hand sanitizers effectively reduced the number of E.coli
counts (CFU) by averages of 10.2000 (92.7% reduction) and 10.2333 (93.03% reduction) respectively.
While the BC Centre for Disease Control recommends 60 percent alcohol hand sanitizers to prevent the
spread of germs, this research showed that alcohol-free hand sanitizers with sulfactants, allantoin, and
benzalkonium chloride (SAB) formula is just as effective in killing germs. Therefore, EHOs/PHIs can
educate the public and operators on the advantages and disadvantages on the two types of hand sanitizers in
preventing the spread germs during the flu season and give practical advice or guidance on which type of
hand sanitizers would be most appropriate in restaurants for example., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, Alcohol-based hand sanitizers, Benzalkonium chloride, E. coli, Alcohol-free hand sanitizers
Background and Purpose: Outbreaks of enteric diseases in schools and daycares are common. It is possible that these outbreaks could be propagated via fomites in school settings, such as playground equipment that is not regularly cleaned. Studies thus far have provided conflicting results on the level of contamination present on fomites in the school setting. This project is intended to assess the level of microbial contamination present on elementary school playground surfaces as a result of hand contact from school children. Methods: Two categories of elementary school playground equipment were sampled in this study; those that are likely to see regular hand contact from children and those that were not likely see hand regular hand contact from children. 30 surfaces of each category were swabbed and the media will be plated and incubated to enumerate total coliforms and E. coli.
Results: The mean number of total coliforms on high hand contact surfaces was 0.2333 cfu/100cm2, while the mean number of total coliforms on low hand contact surfaces was 0.2667 cfu/100cm2. The t-test analysis of total coliform results produced a p-value of 0.5566. The mean number of E. coli on high hand contact surfaces was 1.1333 cfu/100cm2, while the mean number of E. coli on low hand contact surfaces was 4.9000 cfu/100cm2. The t-test analysis of E. coli results produced a p-value of 0.8019. Discussion: Neither results for total coliforms or E. coli indicated significantly different numbers on high or low hand contact surfaces. This indicates that these total coliform and E. coli may not be present as a result of hand contact.
Conclusion: These results do not support the deposition of coliforms or E. coli on playground equipment as a result of hand contact. However, there is still concern due to the number of samples positive for E. coli. These results suggest the need for practices such as regular hand washing in the school setting after using the playground, regular cleaning of playground materials and EHO inspections of school grounds., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, Playgrounds, Schools, Surface sampling, Sanitation, Total coliforms, Escherichia coli, Abbotsford