I have written about electric fly killers previously, where I described the importance of not locating the unit near to the filling head in order to avoid insect debris ending up in the water.
Electric fly killers are often forgotten once installed and reliance is totally on the company servicing the unit. However, it is important to realise that not all UV tubes maintain adequate performance throughout the year and their efficiency cannot be guaranteed to be at optimum levels all year round.
To maintain a satisfactory level of protection, bulbs may need to be changed more than once a year, particularly where species’ populations peak in the late season, also, traps may be under-specified or poorly sited, for example, a lot of ambient UV reduces effectiveness considerably.
The risk of contamination by flying insects can continue into autumn, and beyond, and protection in the bottling plant or cooler servicing room is critical. So, apart from correct location (at least 2m high and away from windows) it is necessary to check the effectiveness of the electric unit periodically.
Fortunately, there is an easy-to-use monitor that can provide a rapid indication of the condition of UV tubes in any electric fly trap. The UVA meter, indicated in the photo, measures tube condition quickly with no calculations necessary. This enables plant supervisors, or indeed, auditors, to record output using a simple 1- 10 scale. There is a moving bar of LED lights which also changes colour according to the condition of the tube. The unit is permanently calibrated and the batteries are user-replaceable with a typical battery life of two years.
Ideally, the bottling plant should be sealed off from the surroundings with close fitting doors and small hatches on conveyors. A door of transparent plastic strips is not always effective and the light from the electric fly killer can actually attract insects into the bottling plant if it is not well sealed.
As a final point, it is interesting to note that an ozone atmosphere generated around the filler is a natural deterrent for insects. This atmosphere will also kill bacteria, although long exposure is harmful to humans.