It’s not a
wonder why we choose to combine limes with drinks, and lemons with fish or
vinegar with fries. It’s all about that strong distinct flavor combined with
the tastes of many of our favorite indulgences. The thing common about these
additives is that, well they taste awesome, but also that they are all organic
acids, a certain category of disinfectant. Acids are typically sorted into two
groups: Inorganic acids and organic acids. Inorganic acids are typically known
as ‘harsh’ acids and lack a –COOH functional group in its chemical structure.
Organic acids are known as ‘carbonic’ acids which contain a –COOH functional group. When you think “acid”
you may revert back to the searing, corrosive substances we see in movies that
burn through everything. However, the strength of an acid, and its disinfection
characteristics, is largely proportionate to the concentration in which it is
encountered. Recently, organic acids have become a newer phenomenon in general
hard surface disinfection due to their trendy attributes. However, certain
characteristics of organic acids can diminish their disinfection grade point
average.
such as citric acids from lemons, generally lack good cleaning capability and
fail to dissolve greasy substance. Further, they do not exhibit detergent like
properties because they do not contain polar and non-polar portions within
their chain. It is possible to increase the acid concentration to improve
cleaning capabilities, however it would sacrifice other key characteristics
desired of modern disinfectant products. Overall, in their typical disinfection
concentration, organic acids do not exhibit strong cleaning behavior.
efficacy of the various organic acid disinfectants is aslo a detrimental
feature. They typically lack a broad spectrum of kill compared to higher level
disinfectants such as bleach and hydrogen peroxide. Their mode of disinfection
depends on the interaction of dissociated protons with microbial surfaces.
Microbial membranes lose integrity in the reaction with free protons in
solution. You may be thinking “Hey, wait! Vinegar and acetic acid have been
used for hundreds of years as methods of disinfection and sanitization.”
However, it is important to note that these only show strength against
relatively easy to kill organisms such as pseudomonas. There is no current data
that concludes that organic acids bolster a broad spectrum of kill.
perspective, the higher the concentration of the acid, the more dangerous it
is. For instance, concentrate forms of acetic acid, citric acid and lactic acid
are all extremely hazardous and can cause serious health problems to many parts
of the body. However, they are safe to consume in the concentrations
encountered in some of the foods we enjoy. The concentration of acetic acid in
vinegar or citric acid in lemons is typically 4% to 8%. That being said, the
safety is mainly dependent on the concentration and the type of organic acid.
cause minimal toxicity in the environment at the concentrations they are used
as disinfectants. This is because of their high solubility in water. When
introduced into aquatic environments, the acids become diluted and thus less
toxic. Furthermore, they cannot bio-accumulate within organisms or the
environment because of this high water solubility. Finally, the degradation
products of organic acids do not pose any threat to the environment, and are deemed
“readily biodegradable” by the EPA.
would rate organic acid disinfectants based on the key decision making
criteria:
Disinfection – C to D
range based on concentration and type of organic acid. They range from 10
minutes to hours for contact time.
Kill – D
most daunting feature of organic acids because there is not enough data to show
efficaciousness against a wide variety of both easy and difficult to kill
organisms.
Effectiveness – C to D
do not exhibit high detergency properties, however it is closely tied to the
concentration of the product.
– B to C
are generally safe compounds as encountered, however they can become hazardous
at high concentrations.
Profile – A to B
disinfectants are readily biodegradable and easily dissolved in water, making
them preferable to the environment.
Effectiveness – A to B
availability, organic acids are usually cost effective methods; however price
increases as concentration rises.
acids and other disinfectant chemistries, stay tuned to www.infectionpreventionresource.com .
