pH: Is it an appropriate indicator of product safety?
Abstract
There is much confusion a mong cleaning and disinfectant users
rega rding pH and wha t i t mea ns wi th respect to a product’s cleaning
or killing properties , its materials compa tibility as well as i ts ra ting
wi th rega rds to i ts toxi ci ty / ha za rd profile. The intent is to dispel
these misunders tandings and provide the facts to hel p increase your
confidence i n your choi ce of cleaning or disinfectant chemistry.
Background
pH (or the powe r of hydrogen) is the uni t of measure used to express
the degree of a cidity or al kalinity of a wa ter-based subs tance. It is
expressed as a number ra nging from 0 to 14 (0 pH and 14 pH would
be the highest a cidi c and alkaline media respecti vel y and pH of 6-8 is
considered to be neutral ).
The pH is relevant, because i t shows us i f the solution is a cidi c, neutral
or alkaline but a pH value alone is not the sole indi ca tor in
determining the s trength of di fferent types of a cids . The following
table provi des a listing of va rious subs tances a nd thei r associated pH
value:
Substance
Stoma ch a cid
Vinega r
Lemon Jui ce
Cola
Orange Jui ce
Toma to Jui ce
Bla ck Coffee
Detergents
Milk
Bl ood
Sea wa ter
Milk of Magnesia
Domes ti c Blea ch
Qua terna ry Ammonia
Compounds
Caus ti c Soda
pH Value
1.0
2.0
2.4
2.4
3.0
4.0
5.0
3-10
6.8
7.4
8.0
10.7
8.0-11.0
8-11.0
14.0
Acids and Toxicity
Vi tamin C, or ascorbi c a cid, is found i n ma ny frui ts and vegetables we
commonl y ea t. Vinega r, or a ceti c a cid, is a common a cid tha t can be
used as a condiment, a pi ckling solution or a cleaning solution. Ci tri c
a cid is present in ci trus frui ts such as lemons , limes , oranges , and
grapefrui t as well as pineapple. Many foods use ci tri c a cid as
preserva ti ve to control the a cidi ty. Phosphori c a cid is used widel y in
cola as a fla vouring a gent to gi ve a product i ts ta rtness. Sorbi c a cid is
a preserva ti ve tha t is also widel y used in food production. The usage
of these a cids in food ei ther naturall y or as addi ti ves illustra tes tha t
such a cids a re not toxi c and a t the appropria te concentra tions they do
not pose an occupa tions heal th safety concern.
Food Acids Versus Non-Food Acids
Acids ca n further be di vided into different ca tegories ; food acids and
non-food a cids . For the purpose of this dis cussion we will focus on
food a cids .
Food a cids a re those tha t a re not toxi c and a re found na turall y in food
including a ceti c a cid, phosphori c a cid, ci tri c a cid, ascorbi c a cid,
ca rboni c acid, sorbi c a cid, etc. These acids a re also referred to as weak
a cids . This means unlike s trong a ci ds, they a re not completel y ioni zed
in the solution. If these weak a cids a re ca refully formulated in
products such as cleaning or disinfecting formulati ons , they do not
cause any i rri ta tion. Moreover, due to thei r non -toxi c nature, they will
not attri bute to a ny concerns with respect to the product’s toxi city. In
summa ry, a cids in concentra te (undiluted) form can be toxi c,
however, ma ny a cids a re used in food products a t low levels jus t as
they a re in AHP, so to sa y “a cids a re bad or toxi c” is an ina ccura te
and/or unqualified s ta tement.
Is a Low pH Product Toxic or Irritating
You mi ght be s urprised to hea r tha t the vinega r (5% a ceti c a cid
solution) we commonl y use, has pH of about 2 and the cola we drink
has pH of 2.4. Furthermore, the pH of a stoma ch might go as low as
1.0. So how is i t tha t we ca n dri nk cola , or ea t vinega r a nd ha ve a
hi ghl y a cidi c envi ronment in our stoma chs and s till survi ve?
Consider cola , one of the world's mos t enjoyed beverages , although i t
contains phosphori c a cid and has a pH of 2.4 we do not worry a bout
any ha rmful side effects from consuming and certainl y do not pani c if
we spill i t on our s kin or clothes. Why is this? We know tha t coke is
not toxi c, and the amount of phosphori c a cid used in i t is low. If on
the other hand, you ca me in conta ct wi th the concentra ted a ci d used
in cola before i t was diluted into the recipe you might injure yourself
or experience chemical burns .
PTSHH0120.0(06/2015)
pH: Is it an appropriate indicator of product safety?
When i t comes to cleaning and disinfectant products, some people
ma y be sensiti ve to s ome products or ingredients used i n the
formula tions . This does not mean tha t the product is considered a
skin i rri ta nt. It simpl y implies tha t like food allergies or food
intolerances , people will exhibit di ffering levels of rea ctions
depending on thei r sensi ti vi ties. To further illus tra te consider those
who cannot tolera te milk or other dairy products due to allergi c
rea ctions or di gesti ve i ntolerances . We do not conclude tha t milk
i tself is bad as mos t of us can eat dairy products wi thout ha ving any
problems . In summa ry, pH alone is not a good measure of i rri ta ncy;
several other fa ctors mus t be considered. There a re s tanda rd tes ts to
measure skin and eye i rri tancy; these tests resul ts a re the true
measure.
Are all Neutral pH Chemicals Non-Toxic and Non-Irritating
Not necessaril y. Toxi ci ty and i rri tancy depends on the na ture of a
chemi cal and not onl y the pH. Here a re some examples :
•Chlori ne is an i rrita nt. If you neutrali ze the chlorine solution, you
mi ght reduce the i rri tancy a li ttle, but you cannot make i t noni rri ta ting. This i rri tancy is due to the rea ction tha t ea ch chemi cal has
by i ts na ture, and since chlori ne is a very reacti ve chemi cal, even in
neutral pH, it will be a skin and eye i rri tant.
•Aldehydes , such as formaldehyde or gluta raldehyde , a re toxi c and
a re considered to be i rri tants . It doesn’t ma tter tha t the pH of the
formaldehyde or gluta raldehyde solution that you a re using is acidi c,
neutral or alkaline. In all cases, i t is s till toxi c and an i rri tant.
•Phenol , a re toxi c and a re i rri tants . Again, in all pH ra nges (acidi c,
neutral, a nd alkaline) they will be toxi c a nd considered an i rri tant and
the i rri ta tion/toxi ci ty will va ry with the concentra tion of the phenol.
•Enzyma ti c-based cleaners . Al though such solutions typi call y ha ve
neutral pH, most enzymes , by their nature rea ct wi th skin and can
cause allergic rea ctions. Therefore, i f the product contains an effecti ve
amount of enzymes in order to ha ve good cleaning effi ca cy, this
product will mos t likel y be a s kin i rri tant. However, the formula tors
sometimes use very low levels of enzymes in thei r product to make
thei r product mild to s kin, in case of conta ct, but this leads to poor
cleaning performance.
•Al cohol as the main ingredient in a product can dry the skin, and
mi ght be an i rri tant. It again doesn’t ma tter if the solution is acidi c,
neutral or alkaline. Al cohol will still dry the skin i n all cases and can
s till be i rri tating.
Implications for AHP®
®
AHP Disinfectants provide the perfect balance between safety and
efficacy
•AHP® has low levels of Hydrogen Peroxide a t the in use dilution,
lower even than some products used every da y by consumers to
whi ten teeth, clean conta ct lenses or even disinfect a wound, and
therefore is designed to be easier on empl oyees and occupa nts
resul ting in protocol compliance
®
• AHP provi des a HMIS ra ting of "0", meaning i t has been proven to
be non-toxi c, non-i rri ta ting to eyes and skin and non-skin sensiti zing
and does not requi re the use of personal protecti ve equipment to
handle
•The lower pH for AHP® (1.8-3.0) is due to the usage of these food
a cids i n i ts formula. Hydrogen peroxide is also a food addi ti ve and is
found in many foods as a preserva ti ve such as milk or honey
AHP® Disinfectants are One-Step Disinfectant Cleaners
•AHP® has powerful surfa ctants, whi ch means i t cleans while i t
disinfects surfa ces and equipment, resul ting in l ower cost a nd faster
resul ts .
AHP® Disinfectants have realistic contact times
•Short conta ct times ensure surfa ces remain wet for the requi red
conta ct ti me, providing comfort and confidence tha t disinfection has
occurred
AHP® Disinfectants are compatible
®
•AHP formulations a re tes ted to ensure compa tibility tha t preserve
your inves tments i n equipment, furni ture, and building surfa ces
AH ®P Disinfectants are environmentally sustainable
•AHP's ® acti ve ingredient, hydrogen peroxi de, breaks down into wa ter
and oxygen lea ving no a cti ve residues
•AHP® is formulated to ensure tha t i t will not negati vel y impa ct
indoor ai r quality
PTSHH0120.0(06/2015)