A low pH is better for the animal skin and still has an antibacterial effect

By Jan van Wyhe-Storgaard, Biochemist, Vilofoss

A pH above 12 will kill most bacteria
Hygiene powder products that kill bacteria on the basis of high pH are typically based on hydrated lime or similar products. Those raw materials have a highly alkaline pH of 12,4 which makes them capable of killing most pathogenic bacteria. The antibacterial effect is created from the corrosive effect that leads to a breakdown of the cell membrane of the bacteria and subsequently death.

Hygiene powder products with pH 12 is corrosive to animal skin
The corrosive effect does not stop with the bacteria, but also corrode and breakdown any animal skin surface that may come into contact with hygiene powder products with high pH. The results from this corrosive effect can be a severely weakened skin surface and reduced defence system. Therefore, we cannot use alkaline hygiene powder products with high pH to control and kill bacteria in resting areas, because the animals will get into contact with the powder and suffer from skin burns and increased risk of infection. 

Hygiene powder products with pH below 4 are ideal for controlling bacteria in animal resting areas
Controlling and killing pathogenic bacteria can also be achieved at a pH below 4. The reason is that most pathogenic bacteria can live and survive at a pH between 4 and 12, so if the pH in the environment is pushed below or above, it is possible to create an antibacterial effect. But since animal skin itself has a natural low pH, it is not sensitive to low pH. In fact, animal skin can accept a pH down to 2 before it will become irritating. So, there is an antibacterial window between pH 2 and 4, where bacteria will suffer without damaging the animal skin. At the same time the low pH will support the skin and sebum, and increase the resistance towards bacteria and ammonia. Finally, since hygiene powder products with a pH below 4 are acidic, they are capable of neutralising alkaline products like ammonia.  

Illustration of the skin defence system and impact by harmful products like hydrated lime, limestone and ammonia.

pH of different components in the animal barn. Animal skin has a pH close to the natural animal environment and natural bedding, but far away from the high pH in the barn. This is one of the reasons, why housed animals have a higher incidence of infections and diseases. Stalosan F has a pH of 3,5, which supports the low pH of the skin. Hygiene powder products with a pH of 12 or above are based on hydrated lime and they breaks-down and counteract the low pH of the skin.