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Hard Surface Cleaning Performance of Six AlternativeHousehold Cleaners lJnder Laboratory Conditions
Wanda Olson, Donald Vesley, Marilyn Bode, Polly Dubbel and Theresa Bauer
AbstractIn thís laboratory sludy, several commercially available household bathroom and
kitchen cleaníng products, with and without EPA registered disinfectant properties, werecompared to several "alternative" products (lemon juice, vinegar, ammonia, baking sodaand borer). High pressure decoratíve laminate tiles were cleaned mechanically using aGardner Abrasion Tester. Test criteria included microbial reduction, based on remainingcolony forming units of a tracer organivn (Serratia nnrcescens), and soil reduction (ofsimulated bathroomand kitchen soilformulations) based on subjective grading by a panelof individuals. Among bathroom cleaners, the commercial cleaners and vinegar gave themost effective microbial reduction while a commercial cleaner without disinfectant wasmost effective at soil removaL Among kitchen cleaners, again the commercial products andvinegar were most effective at microbial reduction while the commercictl cleaners andammoniq were most effective at soil removal.
any groups and agencies pro-mote the use of alternativehousehold cleaners because of
the belief that they are environmentallypreferable to commercially formulated hardsurface cleaners. These alternative clean-ers include food products such as vinegarorbaking soda as well as cleaning and laundryaids such as borax or ammonia.
The "recommended uses" of most ofthe alternative cleaners are for general
cleaning, but some of them are also recom-mended as alternatives for disinfectants.Household cleaners that are registered as
disinfectants must meet testing requirementsof the U.S. Environmental ProtectionAgency (EPA) and it is recognized that the
alternative cleaners do not meet this crite-rion. The purpose of this project is to test
and compare the efficacy ofthese alterna-tives using both soil removal and microbialreduction (which includes both physicalremoval and cidal action) as the evaluationcriteria. These alternative products weretested as single ingredient products eventhough in actual practice some of them are
mixed together in make-your-own recipes.Several researchers have studied the
role of contaminated surfaces in the homeand the spread ofrespiratory and intestinaldiseases. According to Gerba(l),household
surfaces can play a significant role in thetransmission of viruses and bacteria thatcause infectious diseases such as the com-mon cold and flu and intestinal diseases.Propercleaning methods areamajordefenseagainst the spread ofthese microbes because
one is more likely to "pick up viruses fromtouching contaminated surfaces than fromshaking the hand of someone who is in-fected" (2).
An examination of more than 200homes in England documented the pattemof bacterial contamination in the homeenvironment. Sites where cleaning meth-ods needed improvement included hardsurfaces and textile products in the kitchenand bath areas (3). In a study of foodpreparation in the household kitchen, worksurfaces were identified as potential areas
of contanination requiring disinfection (4).The researchers were concerned that"housewives are content if their kitchenappears to be clean." There may be fecalcontamination of surfaces in homes withinfants and toddlers, and a recent studyrevealed contamination of surfaces in out-of-home child care settings (5).
MethodsThe surface chosen for these tests was
a high pressure decorative laminate. The
material was cut into 17" by 7" sections(tiles). The center section of each tile wasartificially soiled with a simulated bathroomsoil or a simulated kitchen soil. A microbialagent (Serratia marcescens) was appliedover the soiled section. Alternative clean-ing products and commercially formulatedhard surface cleaners (referred to as com-mercial cleaners in the remaining text) wereused to clean the surface; the commercialproducts were used as a point of reference.Complete soil test methods are availablefrom the authors. For bathroom cleaners,six tiles per cleaning product were testedand for kitchen cleaners, I 0 tiles per productwere tested.
The simulated bathroom soil testmethod was a modification of a methodbeing developed by ASTM. The soilmixture was applied to the sample surfaceby dipping a mini-trimmer paint applicarorinto the mixture, then "painting" the mix-ture on the test surface. The soiled sampleswere heated in a 70oC convection oven forone hour and were cooled overnight.Samples were tested for soil removal withinone week after soil application. The soilwas composed of the following:. 4.5 g synthetic sebum. 3.0 g stearate premix. 0.6 g carbon black. 1.5 g super mix dirt. 40,29 g sodium stearate. 259.71g deionized HrO
The simulated kitchen soil was a
modification of a fatty acid sebum soil. Thesoil mixture was applied by adding 2.0 mlwarm soil to each sample surface using a l0cc syringe; a mini-trimmer paint applicatorwas used to spread the soil. The soiledsamples were dried and were stored for 12
days prior to cleaning. The soil was com-posed of the following:. 20 g stearic acid. l0 g Crisco@. 20 g palmitic acid. l0 g linoleic acid. 5 g squalene
January / February 1994 . Journal of Environmental Health,27
Alternative cleanersLemon juiceVinegarBaking sodaBoraxAmmonia
lvory Liquid@hand dishwashingliquid
Spic and Spanwith Pine@
Clorox Clean-up@(registered disinfectant)
Comet Cleanserwith Chlorinal@(registered disinfectant)
Commercial hard surface cleaners
Bathroom & kitchenBathroom & kitchenBathroom & kitchenBathroomKitchen
Kitchen
Bathroom & kitchen
Bathroom & kitchen
Kitchen
40 ml-O.10 g/lcalciumcarbonate
0.03 g/l magnesium carbonatewarm deionized water
40 ml undiluted40 ml undiluted'10 g baking soda + 40 mlwater10 g borax + 40 mlwater40 ml 1:1 dilution ammonia
with water40ml 1:10 dilution lvory Liquid@
with water
40 ml undiluted
40 ml undiluted
10 g Comet@ + 40 mlwater
Table 1.Cleaning products and use formulations for simulated bathroomand kitchen soils
CleanerSimulated soileleaned Formulation
Synthetic hard water Bathroom & kitchen
plied from the same stock culture for allcleaning products and therefore would notbias the results.
A Gardner Abrasion Tester was used
to clean the soiled samples. For each test a
cleaning product was applied to the clean-ing face of a new sponge which had beensoaked in warm synthetic hard water (re-
ferred to as water in the remaining text) toadd 70 g water to the dry weight of the
sponge. The sponges, (3.5" x 5" x 1.5"cellulose) had been previously washed and
dried. The tester was set to complete a
selected number of cycles: 50 for thesamples with the simulated bathroom soilwith microbial agent, and 20 cycles for the
simulated kitchen soil with microbial agent.
The number of cycles was based on trials todetermine where obvious differences incleaning ability between products could be
observed. The types of cleaning productsand their use concentrations are presentedin Table L Products were used full strengthor diluted according to manufacturers' di-rections for cleaning heavy soil.
Four alternative cleaning products wereused on the simulated bathroom soil withmicrobial agent: lemon juice, vinegar,baking soda and borax. Two liquid com-mercial cleaners were used: Spic and Span
with Pine@ and Clorox Clean-Up@, a reg-istered disinfectant. Spic and Span withPine@, at the time of the study, was notregistered as a disinfectant. It has sincebeenregistered.'Waterwas used as acontrol.
The alternative cleaning products used
on the simulated kitchen soil with microbialagent were lemon juice, vinegar, bakingsoda, household ammonia, and a handdishwashing liquid (Ivory@). Three com-mercially formulated cleaners were used.These included Spic and Span with Pine@,
a liquid; Clorox Clean-Up@, a liquid andregistered as a disinfectant; and Comet@with bleach, a dry cleanser registered as adisinfectant. Water was used as a control.
The outcome data recorded for each
cleaned sample were thenumber of Serratiamarcescens colony forming units (CFU)recovered after cleaning and an evaluationof soil removal. The cleaned samples werejudged for soil removal by a panel of im-partialjudges. The samples, coded to avoidrecognitionbias, were compared to a sampleboard portraying five differentlevels ofsoilremoval. Each test sample was indepen-dently evaluated by eight judges and as-
' 5 g Paraffin. 160 g bandy black research clay. 160 g isopropyl alcohol. l0 g oildag
The microbial agent was a 24 hourstock culture of Serratia marcescens, ap-proximately 1x10?ml concentration, di-luted in Butterfields phosphate buffer so-
lution to approximately 1xlff/ml concen-tration. This organism was chosen because
it is relatively non-pathogenic to immunecompetent hosts and because it forms a
readily identifiable red pigment so that itcan easily be distinguished from backgroundmicrobes on the surface. Thus a definitivepicture of before and after counts can be
obtained specifically related to the cleaningproduct used. A sterile cotton tipped ap-plicator was used to apply 0.2 ml of theSerratia marcescens mixture to the soiledarea of each bathroom tile, 0.5 ml to thesoiled area of each kitchen tile immediatelyprior to cleaning. RODAC plates con-
tained Standard Methods Agar(SMA) with0.7 gA lecithin and 5.0 g/l polysorbate 80for general purpose neutralization. ThreeRODAC plates were applied to soiled areas
of each tile a) immediately after bacterialapplication and prior to cleaning, and b) tothe soiled area immediately after cleaningexcept in those cases in which the cleaningproduct specified a five-minute productcontact period to allow disinfectant action.Before and after sampling sites were mu-tually exclusive to avoid interference(colony reduction) attributable to the sam-pling method. The RODAC plates wereincubated at25'C for 24 to 36 hours, thencounted using a Quebec Colony Counter.Only redpigmented colonies were counted.At this dilution, all beþre cleaning plateswere Too Numerous to Count (TNTC).Thus, results and comparisons are based
only on after cleaning counts rather than onpercent reduction, with the assumption thatthe initial inoculation was consistently ap-
28. Journal af Environmental Health. Volume 56, Number 6
signed a soil removal score (SRS) from 1
(greatest soil removal) to 5 (least soil re-moval).
Statistical analyses of the data wereconducted on the number of colony form-ing units on each RODAC plate and the soilreduction score for each tile. Analyses Cleaning product pH Mean CFU (SD). Mean SRS (SD)**performed included the analysis of variance Water e.e7 78.1 (89.6) 3.667 (1 .100)
and the Tukey Test.
Results and discussionMicrobial reduction - Microbial
cultures and soil removal results are reported
in Tables 2a and 2b forbathroom soil and inTables 3a and 3b for kitchen soil. For bothsoils there were significant differences inthe microbial reduction within the alterna-
tive cleaner group but not within the com-mercial cleaner group. Among the bathroomsoil cleaners, the commercial cleaners,
vinegar, baking soda and lemon juiceyielded lower microbial counts than boraxand water (Tukey analysis at alpha = 0.05).
Further application of the Tukey analysis to
the low count group revealed that the twocommercial cleaners and vinegar had lowergroup means for microbial counts than
baking soda and lemon juice. For kitchen Cleanersoil cleaners, the three commercial clean- Water
Microbialreduct¡on Soilremoval
Table 2aMicrobial reduct¡on and so¡l removalof simulated bathroom soilwithmicrobial agent from laminated surface us¡ng d¡fferent clean¡ng products,six replications
Alternative cleanersLemon juice 2.93 15.1 (6.7) 4.333 (0.705)Vinegar 3.09 6.1 (5.7) 5.000 (0.0)Baking soda 8,43 12.9 (12.2) 3.900 (0.602)Borax 9.79 54.9 (41 .4) 2.650 (0.515)
Commercial hard surface cleanersWithout disinfectant 9.74 O.2 (0.7) 1.000 (0.0)With disinfectant 12.57 0.0 (0.0) 4.067 (0.252)
" colony forming units of S. marcescens recovered after cleaning*" soil reduction score on 1-5 scale, 1 indicating greatest soil reduction
Table 2bEffectiveness of cleaners on simulated bathroom so¡l as evaluated bydifferences in group means (Tukey test alpha = 0.05)
ers and vinegar had the lowest group mean.
Water and ammonia exhibited intermediate Alternative cleanersresults and dishwashing liquid and baking Lemon juice lntermediatesoda showed the highest counts. Lemon Vinegar Most effectivejuice results were not included due to a lab Baking soda lntermediateerror (plate contamination) which resulted Boraxin too few observations.
Microbial reduction results must be COmmerCial hard SUrfaCe Cleanersinrerpreted with caution. It is clear that for Without disinfectant Most effectiveboth bathroom and kitchen products, low- With disinfectant Most effective
Least effective
Least etfective
High intermediate
Low intermediateLeast etfectiveHigh intermediateHigh intermediate
Most effectiveLow intermediate
est counts a¡e achieved by the commercialproducts - whether or not registered as a
disinfectant. However, vinegar (and to a to break up clumps of viable cells to a dilute than those used in this study, how-Iesserextent,lemonjuice)gavestatistically greater extent and therefore resulted in ever. Although the commercial products
similar results presumably because of its higher colony counts, although the actual andsomeof thealternativecleanersclearlyvery low pH. It is possible that vinegar numberofviablecellswasequivalenttothe resulted in fewer colonies recovered fromoutperformed lemon juice because acetic products with less detergency. the tiles, transfer of the microbes to the
acid is known to be a more effective bac- It is also important to note that this sponge could have occurred but was nottericidethancitricacid. Senatiamarcescens sampling protocol does not distinguish tested. Thus attention to the cleaningis typical of gram-negative enteric bacteria between cidal action and physical removal mechanism and ultimate fate of organisms
which are known to be sensitive to acid in the lowering of viable counts. Previous physically removed but not killed may be
conditions. Water and ammonia were in an research on dilute solutions of the alterna- important, as well as the absence of or-intermediate group while dishwashing liq- tive cleaners borax, vinegar, ammonia and ganisms from the hard surfaces.
uid and baking soda yielded the highest baking soda have shown that they did not
microbial counts on the kitchen soil. One meet EPA guidelines (cidal action) for Soilremoval---Theresultsarereportedpossible explanation for this phenomenon registered disinfectants (6). The concen- as a mean score for 50 cleaning cycles foris that the detergency action of the trations of the alternative cleaners in the thebathroomsoilandfor2Ocleaningcyclesdishwashing liquid and baking soda tended Rubino study were 16 to 32 times more for the kitchen soil. With additional cycles
January / February 1994 . Journal of Environmental Health,29
Table 3aMicrobial reduction and soil removal of simulated kitchen soilwithmicrobial agent from laminated surface using different cleaning products,10 replications
* colony forming units of S. marcescens recovered after cleaning** soil reduction score on 1-5 scale, 1 indicating greatest soil reduction
Table 3bEffectiveness of cleaners on simulated kitchen soil as evaluated bydifferences in group means (Tukey test alpha - 0.05)
baking soda and lemon juice-were notsignificantly different from the commercialcleaner with disinfectant.
Forremoval of kitchen soil, ammonia,an alternative cleaner, was in the high soilremoval group with all the commercialcleaners while, lemon juice and vinegarwere in the low soil removal group. Bakingsoda, dishwashing detergent (hand) and
water were in separate middle groupings.
Tables 2b and 3b compare the effectiveness
of the cleaners on both microbial reductionand soil removal.
ConclusionsIn this laboratory study, alternative
household cleaners were used to clean highpressure decorative laminate surfaces soiledwith simulated bathroom or kitchen soilsover which a microbial agent had been
applied. The cleaners were then evaluatedon their effectiveness in reducing microbialcontamination, as measured by the number
of colony forming units cultured aftercleaning, and their effectiveness in re-
moving soil. Because the simulated bath-room soil was a tougher soil to remove than
the simulated kitchen soil, the soil removalresults are somewhat different for the twosoil types. The cleaners used were chosento represent cleaners that are often recom-mended for cleaning bath¡oom or kitchensoils and were compared with commercialhard surface cleaners used in those tworooms.
The results indicate that compared tocommercial cleaners, the alternativecleaners as a group are less effective in bothmicrobial reduction and soil removal.However, the alternatives vary in their ef-fectiveness. Two alternative cleaners-borax and ammonia-were more effectivein soil removal than the other altemativecleaners. However, borax was not at alleffective in reducing microbial contami-nation. Vinegar was more effective inreducing microbial contamination than the
other alternative cleaners but was least ef-fective in removing soil.
All of the cleaners, including water,
could conceivably have removed the soilfromthe tiles with enough cleaning strokes.Therefore, consumers who wish to use al-ternative cleaners may find them effectivein removing soil if they are willing to workharder. The microbial reduction in thisresearch could be the result of either cidal
Gleaning product pH Mean CFU (SD)*Water 9.97 141.3 (82.4)
Alternative cleanersLemon juice 2.93 73.9 (101 .9)Vinegar 3.09 0.6 (2.3)Baking soda 8.43 336.4 (132.2)Ammonia 11.81 12ô.9 (82.3)Dishwashing liquid 9.81 302.9 (151.8)
Commercial hard surface cleanersWithout disinfectant 9.74 0.0 (0.0)With disinfectant 12.57 0.0 (0.0)Dry cleanser with 10.74 0.0 (0.0)disinfectant
Mean SRS (SDf-4.588 (0.520)
4.e88 (0.112)5.000 (0.0)1.175 (0.382)1.000 (0.0)2.863 (0.381)
1.000 (0,0)1 .013 (0.1 12)1.000 (0.0)
CleanerWater
Alternative cleanersLemon juiceVinegarBaking sodaAmmoniaDishwashing liquid
Microbial reduct¡onlntermediate
(not included)Most effectiveLeast effectivelntermediateLeast effective
SoilremovalLow intermediate
Least effectiveLeast effectiveHigh intermediateMost effectiveHigh intermediate
Most effectiveMost effectiveMost effective
Commercial hard surface cleanersWithoutdisinfectant MosteffectiveWith disinfectantDry cleanser withdisinfectant
Most effectiveMosl etfective
all cleaners may have had the same soilremoval score. For soil removal under the
test conditions, there were significant dif-ferences within the alternativecleaner group
for both the kitchen soil and bathroom soil.However, within the commercial cleaners,
there were significant differences forbathroom soil only. Because the bath¡oomsoil was baked onto the tiles, it was a muchmore difficult soil to remove.
The results of the Tukey test for the
difference in group means divided the
cleaners into several groups. For removalof bathroom soil, the high removal group
consisted of one commercial cleaner withoutdisinfectant, and the low removal group
consisted of one alternative cleaner, vinegar.The alternative cleaner with the best soilremoval score was borax. The soil removalscores of the other alternative cleaners-
3O. Journal of Environmental Health. Volume 56, Number 6
action or physical removal and transfer ofthe microbes to the sponge. Washing the
sponge with a disinfectant or drying the
sponge may ultimately destroy the microbes.
Because the microbe used for testing
in this research was susceptible to acid
conditions, the acidic cleaners, particularlyvinegar (acetic acid) were effective in re-
ducing microbial contamination. For
cleaning soil with these types of microbes,
a vinegar rinse following cleaning with amore effective soil removing alternative
cleaner may be effective in reducing mi-
crobial contamination. However, when
there are specific health related concerns
(such as the presence of neonates or im-
munosuppressed family members) which
signify the need for microbiocidal action,
consumers should be aware that only reg-
istered disinfectants have been tested using
standard methods to show cidal action.
This laboratory study is useful in evaluat-
ing some differences among alternative
cleaners. Further testing of these products
needs to be conducted in the home environ-
ment under conditions of consumer use.
Wandq Olson, DePt. of Design,Housing and Apparel, Uníversity of Min-nesota, 240 McNeal Hall, 1985 BufordAve., St. Paul, MN 55108.
References
I . Gerba, C. ( 1992), Meeting consumerneeds
for health, Dete rgents inDepth, 92, Proceedings
from the video conference, CleaningProducts...In Our Homes, In Our Environment,
April 1992, SDA, New York, NY.2. Ansari,S.A., S.A. Sattar, V.S. Springthorpe'
G.A. 'Wells and W. Tosotwaryk ( 1988), Rotavirus
survival on human hands and transfer of infec-
tious virus to animate and nonporous inanimate
surfaces, J. Clinical Microbiol. 26:1513-1518.
3. Scott, E., S.F. Bloomfield and C.G. Barlow(1982), An investigation of microbial contami-
nation in the home, J. Hyg. Camb.89l:2'19-293.
4. Bomeff, R.H.,J. Woittig andR. Edenharder
(1988), Distribution of microorganisms in
household kitchens II. Communication: Criti-cal evaluation of the results and conclusions,
ZbL Bakt. Hyg. B 186:30-44.
5. Van, R., C.C. Wien, A. Morrow and L.K'
Piekering (199 l), The effect of diaper type and
overclothing on fecal contamination in day-care
centers, JAMA 265 (14): I 840-l 844'
6. Rubino, J. and J. Bauer (1992)' Antimi-crobial activity of environmentally "green"
products,Aåsrra cts of the Annual Meeting of the
American Socíety of Microbiology, New Or-
leans, LA.
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January / February 1994 ' Journal of Environmental Health' 31