The recent outbreaks of Avian Influenza in three continents put question marks behind the application of biosecurity programs. One of the identified vectors for spreading the disease is the so called "mobile vector" caused by vehicles and people ( catching crews, collection of litter and dead birds, transport from the hatchery and to the processing plant, feed delivery trucks, … ) .

In this article, we want to share some advices on vehicle hygiene. The first rule is that hygiene consists of two parts : CLEANING and DISINFECTION. Cleaning is the removal of (organic) dirt in which micro-organisms live.

At the outside, it's the "traffic film". This is a build up of dirt consisting of dust and grease (or petroleum and exhaust residues) that is attached to the body by the electrostatic load on the vehicle. During summer time, dead insects will be added to the traffic film (by themselves already a carrier of different bugs).

At the inside, the dirt depends on the load : it can be albumen and yolks from broken hatching eggs; fluff and droppings from day old chicks, droppings from broilers ready to slaughter, feed left overs, …

So both inside and outside, the dirt is mainly organic. Therefore, a slightly alkaline detergent should be used (alkaline products remove organic dirt like fats and certain proteins; acids remove inorganic dirt like lime scale). However, if the product is too alkaline, or contains sodium hydroxide or chlorine, it will corrode the body of the truck, especially the aluminium parts. In other words, a SPECIAL product should be used (such as HATCHONET ™, free of sodium hydroxide and chlorine, but rich in surfactants or wetting agents that will decrease the surface tension and break through the dirt). If only water with high pressure is used, it won't be possible to remove these specific types of dirt.

The list below shows what the characteristics of detergents are :

• Wetting: decreases surface tension
• Dispersing: splits up dirt particles
• Emulsifying: splits and suspends oil and fat
• Suspending: floats and carries away dirt particles
• Sequestering: dissolves salts

Ideally, the detergent should be applied as a foam, using a foam lance and a high pressure sprayer ( min. pressure 500 psi), starting at the bottom and going up with the lance. The foam allows for a better coverage, and doesn't dry up that fast, ensuring the chemical does it's job, described in table 1. Therefore, it's advisable to clean first the inside and then the outside (especially during summer). Avoid vehicle washing in the sun .

After the cleaning, the vehicle shampoo or detergent should be rinsed off with plain water, before the disinfectant is applied. Here fore, the best result is obtained when starting at the bottom and going up , moving the high pressure lance from the left to the right and back. Then, do a quick rinse from the front towards the end to remove the remainders of the foam. ( The high pressure replaces the brush : no need for "elbow grease").

A good cleaning job should remove about 80 % of the microbes. On a clean surface, it's possible to eliminate log 4 ( i.e. 99.99 %) of the remaining 20 % microbes with an edequate disinfectant.

So what are the major criteria for a good vehicle disinfectant ?

1. efficacy : it should cover the full spectrum : bactericide, virucide, fungicide and sporicide to kill ALL types of bugs, in all temperatures, pH values and water hardnesses and in presence of some organic load ; therefore check if the product has the appropriate AOAC claims ! [ The specific AOAC standard works with > 5 % organic load and in 400 ppm CaCO3 hard water. VIROCID ® passed the Avian Influenza test per AOAC at 1:400 only.]

2. safety : for people : not carcinogenic ( containing no formalin) and for the truck body : it should obviously be not corrosive (it should therefore have a neutral pH) neither affect the paint

3. residual activity : never rinse the disinfectant ! Particularly when applied as foam, the disinfectant will remain active a longer time and prevent early re-contamination.

4. versatility : the product should be applicable by spraying, foaming and fogging, without having to add any carrier or other additives.

Often, critical places are forgotten to treat, such as the underneath of the vehicle and the inside of the wheel arches. One of the most contaminated areas are the steps towards the cabin. Also the driver's cab itself should be disinfected inside ! Equally important is the replenishment of farm gate wheel dips. Last but not least, we've observed wheel disinfectant pads that were smaller than the circumference of the vehicle's wheels !

(Automatic) spraying installations, reaching the underneath and the arches deliver a better job. Here, the non-corrosivity is even more important as different materials will be reached. They also assure "fresh" disinfectant to be used .

Don't forget to disinfect the feed delivery pipes of the feed trucks. Bulk carriers can be disinfected by misting or fogging, hence the importance of the product's versatility (ready to use for spraying, foaming and fogging).

If plastic chick boxes are used, they usually go back to the hatchery. There, they can be washed (and disinfected) in the tray washing machine (tunnel). The same procedure is required as for hatcher trays. Also crates for broiler transport should be washed and disinfected after every use. So should all tools that come with the vehicle (shovels, …) .

The principle for all these objects are the same : first wash, then disinfect. In a cratewasher, the non-foaming product DM-CID ™ is recommended. Tools and all other equipment can be pressure washed with the foaming HATCHONET ™. All disinfection can be done with VIROCID ™.

As a summary, we can state that it's advisable to clean the truck on a daily basis at night and to disinfect it at every arrival on farm.

Source: CID LINES - June 2006