Quaternary Ammonium Compounds
MAH White Paper
Executive summary
Quaternary Ammonium Compounds, also known as QACs or Quats are a group of compounds including
Didecyl Dimethyl Ammonium Chloride and Benzalkonium Chloride. They have been a common
ingredient in many farmyard sanitisers for years, thanks to their disinfecting properties.
Advantages to Quats include low odour and toxicity compared to other active ingredients, plus good
tolerance to a wide range of pH conditions. They are suitable for multiple tasks, being non-corrosive to
metals. However, they leave a sticky residue after application which, in recent years, has been recorded
at higher levels than agreed defaults. Side effects of human exposure to Quats include: skin and respiratory
irritation, allergic reactions, caustic burns, nausea and vomiting. More serious repercussions are possible
for people with compromised immune systems.
Serious concerns have been expressed across the farming and food production industry over the
continued use of Quats and their effect on the supply chain. Earlier this year, milk processor, Arla
announced they will no longer accept any milk that has come into contact with Quats at any point in the
supply chain from 1 July 2014 onwards. UK dairy sites have followed suit.
All products developed and manufactured by MEDSA Animal Health contain no Quats whatsoever. We
omit peracetic acid and antibiotics too, and at the time of writing, it is believed that we are the only UK
company that does not include Quats in its cleansing products - making us a unique choice for farm
sanitisation.
Quaternary Ammonium Compounds
For a long time, Quaternary of Ammonium Compounds, also known as QACs or Quats, have been
included in all kinds of products, from sanitisers to polyurethanes1. Their disinfecting properties have made
them a popular ingredient, used for a number of farmyard tasks.
However, more recently, residues have found their way onto plant products in several countries at levels
higher than those initially agreed by the industry. As a result, guidelines have been put in place to monitor
the use of Quats and concerns have been expressed over their continued use and effect on the whole
food chain.
This article looks at how and why Quats have been used in the farming industry, the risks involved and
other methods of sanitisation.
A description of Quats
Quats are a group of compounds including Didecyl Dimethyl Ammonium Chloride (DDAC) and
Benzalkonium Chloride (BAC). In slightly more scientific detail, they are derivatives of ammonium
compounds, (NH4+)Y−, in which all four of the hydrogens bonded to nitrogen have been replaced with
hydrocarbyl groups, or univalent groups formed by removing a hydrogen atom from a hydrocarbon like
ethyl or phenyl2.
First uses of Quats as a disinfectant date back to 1916, although it was not until 1935 that it was discovered
that they had excellent bacteria-killing properties3. Used alone, they work reasonably well as a sanitiser,
MEDSA Animal Health
www.medsaanimalhealth.com ● 0844 55 6 55 77
The Black Barn, Runfold St George, Farnham, Surrey, GU10 1PL. United Kingdom.
MEDSA Animal Health Limited is part of MEDSA Group Limited, registered in England & Wales. Company No. 5084053
but combining them with a compatible non-ionic detergent will increase their efficacy. Normally noncorrosive, overly-strong concentrations could corrode mild steel or iron4.
Benefits of Quats
Quats are widely available and are an effective sanitiser and disinfectant, thanks to their antimicrobial
effects. Their use has been licensed within the food industry specifically as a plant protection product or
as a biocide for disinfection5.
Advantages to using them include low odour and toxicity compared to other active ingredients, as well
as a good tolerance to a wide range of pH conditions, making them versatile and suitable for a broad
range of tasks. Quats are non-corrosive to metals and don't bleach textiles, although they must be diluted
to the right strength to gain optimum efficacy and to prevent too strong a mixture from causing damage6.
Unlike their bleach-based counterparts, Quats need longer contact with a soiled surface to work, with
some products advising waiting at least ten minutes before wiping them off. Advice is also given to rinse
surfaces treated with Quats before bringing food into contact with them. This is due to the sticky residue
that can be left behind after the application7.
Adverse effects and risks to health from Quats
Despite their propensity to leave a sticky residue after application, using Quats as a disinfectant on farms
was never expected to have a direct impact on food produced or reared on the premises. Therefore,
specific maximum residue levels were never fixed - a default level of 0.01 mg/kg was applied instead.
In recent years, however, such residues, have been recorded at much higher levels than the agreed defaults
in several countries. Potential causes of residue coming into direct contact with plant products are multiple,
from contaminated water being used for irrigation or crop spraying to cross contamination from
equipment (e.g. milking machinery) disinfected with Quats. Migration of surface residue to food products
has also happened with alarming frequency, for example wooden boxes treated with antifungal products
and then used to store fruit and vegetables.
Some of the side effects for human health caused by the use of Quats on farms include: skin and
respiratory irritation, allergic reactions, caustic burns, nausea and vomiting8. More serious repercussions
are possible for people with compromised immune systems, while prolonged exposure to Quats has also
been linked to asthma and changes in lung function9.
Industry reaction to Quats and residues in the supply chain
As a result of these higher residue level discoveries and serious threats to human health, the Standing
Committee of the Food Chain and Animal Health put firmer guidelines in place in July 2012 to monitor
the use of Quats and to temporarily adjust the maximum residue levels to ensure greater safety in all food
and feed of plant origin. Levels have been adjusted again since then, however, they remain much tighter
than those originally put in place as a default.
Serious concerns have been expressed across the farming and food production industry over the
continued use of Quats and their effect on the supply chain, including the farmer, haulier and dairy.
Earlier this year, major milk processor, Arla announced that they will no longer accept any milk that has
come into contact with Quats at any point in the supply chain from 1 July 2014 onwards. Dairy sites within
the UK have followed suit, introducing a policy banning any substances that may come in contact with
milk and that contain DDAC or BAC.
MEDSA Animal Health
www.medsaanimalhealth.com ● 0844 55 6 55 77
The Black Barn, Runfold St George, Farnham, Surrey, GU10 1PL. United Kingdom.
MEDSA Animal Health Limited is part of MEDSA Group Limited, registered in England & Wales. Company No. 5084053
Testing for the presence of DDAC and BAC is also being considered for inclusion in the National Due
Diligence programme managed through Dairy UK and paid for by the milk industry (including Arla). This
scheme already tests for the presence of pesticides, lead and other toxic substances.
The MEDSA Animal Health Method
All sanitising products from MEDSA Animal Health are manufactured without Quats. We comply fully
with industry-led demands for safer cleaning solutions.
We omit peracetic acid and antibiotics too, and at the time of writing, it is believed that we are the only
UK company that does not include Quats in its cleansing products - making us a unique choice for farm
sanitisation.
Our products rely on a different formula and action to kill germs, bacteria and bugs. This is just as powerful
as using Quats, but it has the added benefit of leaving no residues or taints. Our products have a shorter
dwell time too, and are safer to handle. Farmers can rest assured that they are fully compliant and prepared
for any changes in the law or demands from customers regarding Quats.
We work with experts to create non-toxic, highly effective sanitisers. Find out more about MEDSA Animal
Health at: www.medsaanimalhealth.com
MEDSA Animal Health
www.medsaanimalhealth.com ● 0844 55 6 55 77
The Black Barn, Runfold St George, Farnham, Surrey, GU10 1PL. United Kingdom.
MEDSA Animal Health Limited is part of MEDSA Group Limited, registered in England & Wales. Company No. 5084053
References:
(1) Quaternary Ammonium Compounds. Available: http://sacheminc.com/other-chemicals/quaternaryammonium-compounds-quats/. Last accessed 9 June 2014.
(2) IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D.
McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected
version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A.
Jenkins. ISBN 0-9678550-9-8.
(3) Jeffrey, D.J. (1995). Chemicals used as disinfectants: active ingredients and enhancing additives.
Available: http://www.oie.int/doc/ged/D8966.PDF. Last accessed 9 June 2014.
(4) Jeffrey, D.J. (1995). Chemicals used as disinfectants: active ingredients and enhancing additives.
Available: http://www.oie.int/doc/ged/D8966.PDF. Last accessed 9 June 2014.
(5) MAH briefing document: details TBC
(6) Kerner, Mike. (2013). Disinfectants (part 1). Available:
http://www.cleanfax.com/articles/print/104972-disinfectants-part-1. Last accessed 9 June 2014.
(7) A look at kitchen cleaners and sanitisers. Available:
http://www.foodsafety.wisc.edu/consumer/fact_sheets/Cleaners_Sanitizers.pdf. Last accessed 9 June
2014.
(8) Quaternary ammonium. Available:
http://www.inchem.org/documents/pims/chemical/pimg022.htm#SectionTitle:2.1%20%20Main%20risk%2
0and%20target%20organs. Last accessed 9 June 2014.
(9) Grossman, Elizabeth. (2014). Can killing germs be hazardous to your health? Questions about
"quats". Available: http://scienceblogs.com/thepumphandle/2014/01/31/can-killing-germs-be-hazardousto-your-health-questions-about-quats/. Last accessed 9 June 2014.
MEDSA Animal Health
www.medsaanimalhealth.com ● 0844 55 6 55 77
The Black Barn, Runfold St George, Farnham, Surrey, GU10 1PL. United Kingdom.
MEDSA Animal Health Limited is part of MEDSA Group Limited, registered in England & Wales. Company No. 5084053