Most discussions of the criteria for selecting a good disinfectant start with the cost, the composition of the product and its likely efficacy. These are certainly important considerations. But the pig producer should not forget the aspect of safety. Any chemical used in disinfection must be safe — for people, animals, equipment and the environment.

Safety for the user means the disinfectant cannot be toxic, of course, but there are even potential issues of carcinogenicity with chemicals such as formaldehyde. Some other products may have impracticably low exposure limits.

Personal protection equipment, such as masks, gloves, goggles, coveralls and boots, are always a must. In many countries, national safety standards (OSHA in the USA, COSH in the UK, etc.) describe what is required. To make application and measuring safer and more efficient for staff, they need a disinfectant that is genuinely easy to use. It is generally accepted that liquids are better to measure and mix more easily with water than powders.

Convenience is factor

Moreover, the personnel on the pig unit often find it easier when they can use the same product not only to disinfect surfaces, but also in foot-baths and wheel-dips. With this in mind, all unit managers need to distinguish carefully between a terminal disinfectant and a "sanitiser." Unlike so-called water sanitisers, a terminal disinfectant is not automatically a product that can be added to the pigs' drinking water during production. A registered disinfectant has "claims" showing that it effectively kills certain microbes (e.g. PRRS and PCV2 virus).

The first aspect of safety with disinfection of equipment is that the disinfectant must not be corrosive. This can ideally be achieved with products that have a neutral pH, which is around 7.0. Strongly acid or alkaline products are usually corrosive. Acids may corrode copper and brass; alkalines (particularly when chlorinated) may corrode aluminium.

Obviously it is the metalwork in your pig house that will be most vulnerable to corrosion. This refers not only to galvanised feeder tubes and hoppers, for example, but also to winching equipment, including the steel cables and pulleys on curtain-sided buildings as well as the fans, feed pipes and nipple drinkers. They are valuable assets, so you want to maximise their working life, not destroy them prematurely by applying an inappropriate disinfectant.

Equally, however, the threat can be to concrete. Anyone who has invested in a smooth, easy-to-clean concrete floor does not want it transformed to a cracked, uneven corroded surface that will harbour micro-organisms and be much more difficult to clean and disinfect. Very acidic products will "eat" their way through concrete and cause cracks.

Clear instructions

Good safety recommendations on the label should give clear instructions how to use the product, known in Europe as the "S" codes, and a clear description of the natures of the danger, known as the "R" codes. These safety recommendations refer to the use of the concentrated product, undiluted. Do not let a prejudiced supplier put you off a good economical product by highlighting features that only apply to the concentrate, when it is non-hazardous at in-use concentrations.

Always keep an MSDS on file and at hand. In case of an accident, the solution is water. When chemicals have been spilled on human skin or eyes, rinse immediately with water. When they have been drunk, dilute by drinking as much water as possible.

Safeguard the environment

Think also about safeguarding the environment, which means using a disinfectant that is more than 90% biodegradable according to OECD standards. Disinfectants are not biodegradable if they contain any heavy metals. In Scandinavia, the use of heavy metals in farm chemicals is already forbidden.

Also, phenols don't comply with the OECD biodegradability standards and have hence been banned in the European Union since 2006.

A final safety opportunity is the profile of your supplier. Should your supplier be certified with international standards, such as ISO and /or GMP (Good Manufacturing Practices), then you can be 100% sure that what the label says is also what is inside the drum.