Winter Disinfection: Choosing & Using Disinfectants in Cold Conditions

Winter brings some additional challenges for maintaining effective farm hygiene and biosecurity.

Lower temperatures, increased moisture, mud and organic matter can all make cleaning and disinfection more difficult. Choosing the right disinfectant — and using it correctly — becomes particularly important when temperatures fall.

The good news is that effective disinfection is still achievable throughout the winter months. The key is understanding how temperature, organic matter, concentration and contact time can affect performance.

Why does temperature matter?

Not all disinfectants respond to cold conditions in the same way.

Many disinfectants used in animal production are tested under defined temperature and organic-matter conditions, so it is important to check the manufacturer’s instructions, and the specific efficacy claims for the product you are using.

For example, Defra-approved disinfectants used for relevant animal disease control are tested under specified conditions, including testing at 4°C. Where a Defra-approved product is required, the product, dilution and application instructions on the relevant approval should always be followed.

As temperatures fall, some disinfectants may work more slowly like glutaraldehyde, Quaternary Ammonium Compounds (QAC) and chlorocresol-based disinfectants. Others are relatively less affected by low temperatures like peracetic and peroxygen disinfectants.

This means that simply increasing the concentration of a disinfectant is not the right solution. The product’s approved dilution, contact time and application instructions should always be followed.

Cold weather isn’t the only challenge

Winter conditions often bring another problem: organic matter.

Mud, manure, litter, dust and other organic material can interfere with the performance of some disinfectants. This is particularly important on farms during periods of wet and muddy weather, when surfaces and equipment can become contaminated much more quickly.

This is why cleaning must come before disinfection.

Removing as much organic matter as possible allows the disinfectant to reach the surface and work as intended.

A simple winter hygiene routine should therefore be:

Clean → Remove organic matter → Rinse where appropriate → Allow surfaces to dry where possible → Disinfect

Disinfectant should not be expected to compensate for inadequate cleaning.

Choosing the right disinfectant for winter

There is no single disinfectant type that is ideal for every application.

Different active ingredients have different characteristics, including their performance at lower temperatures and their tolerance to organic matter.

Although peroxygen and peracetic-acid-based disinfectants are generally less affected by low temperatures.  They can be more readily affected by organic matter, which means solutions may need to be replaced  daily where contamination is high.

Glutaraldehyde-based disinfectants can be slower to act at temperatures below 4°C, but they continue to work under cold conditions. However, some formulations can also be mixed with suitable antifreeze agents for winter applications, subject to the manufacturer’s instructions. Intercid, a glutaraldehyde/formaldehyde disinfectant for example is recommended for dilution with either ethanol, propylene-glycol and Isopropanol for temperatures down to -15C.

The important point is not simply to choose a disinfectant because it is described as a “winter” product.

Instead, consider:

• What organisms do you need to control?
• At what temperature will the disinfectant be used?
• How much organic matter is likely to be present?
• What concentration is required?
• What contact time is needed?
• Is the product approved or tested for the intended application?
• How frequently will the solution need to be replaced?

Don’t forget contact time

Cold weather can make it tempting to reduce contact times because surfaces need to be returned to use quickly.

However, disinfectants need sufficient time to work.

The required contact time depends on the product, concentration, target organism and conditions of use. Always follow the manufacturer’s instructions and relevant approval or efficacy information.

For Defra-approved disinfectants, the required dilution and use conditions depend on the specific product and disease/application.

Winter disinfection needs consistency

During winter, hygiene routines can easily become more difficult to maintain.

Bootdip management

Mud builds up more quickly. Water can freeze. Disinfectant solutions may become diluted by rainwater or contaminated with organic material, while cold conditions can make cleaning and drying harder.

These factors make routine checks particularly important.

Check disinfectant solutions regularly and replace them according to the manufacturer’s recommendations. If a disinfectant becomes heavily contaminated with organic matter, it may need to be replaced sooner.

As a simple guide for bootdip replenishment, Hysolv recommends:

A few simple winter building disinfection tips

1. Remove organic matter first
   A dry-clean removing used litter, dust, movable slats and nesting boxes etc.
   Then wash-out with a suitable high foaming cleaner like Alkaliene Blue.
2. Check the temperature
   Know the temperature at which your disinfectant is being applied and check that the product is suitable for those conditions. On cold days, chlorocresols for example may be mixed initially with warm water to the tank to bring the temperature to 7° – 15°C before applying.
3. Use the correct concentration
   More is not necessarily better. Follow the manufacturer’s recommended dilution but also compare this with any relevant Defra approval. Sometimes, manufacturers can be ‘ambitious’ with their claims.
4. Allow sufficient contact time
   Don’t wash away or remove disinfectant before it has had time to work.
5. Watch for dilution
   Rainwater, standing water and wet surfaces can dilute disinfectant and affect the concentration reaching the target surface.
6. Consider the whole biosecurity programme
   Disinfection is only one part of effective farm biosecurity. Cleaning, personnel hygiene, traffic control and preventing the movement of contamination all have a role to play.

Don’t let winter compromise your biosecurity

Cold weather doesn’t have to mean compromised disinfection.

The most effective approach is to understand the conditions in which your disinfectant is being used and choose a product that is appropriate for the application, temperature and expected level of contamination.

With the right product, correct dilution, adequate contact time and good cleaning practices, effective disinfection can be maintained throughout the winter.

If you’re reviewing your farm’s disinfectant programme ahead of winter, speak to the Hysolv team for advice on choosing the right product and application for your requirements.