Buyers of fruit such as apples and pears place strict requirements on the hygiene of fruit. Depending on the retailer and/or the country of destination, very few or absolutely no detectable pathogens may be found on the skin of the fruit. At the same time, the producer is also confronted with stringent residue standards (MRL) with regard to chemicals that could have prevented the growth of these germs in the first place.
That is why CleanLight wanted to determine whether their disinfection technique, known from the cultivation of flower bulbs, would also be effective on hard fruit. Maarten VanEijk from CleanLight says: “In the flower industry, disinfecting with UV is already used quite commonly to combat germs such as Fusarium on the bulbs of tulip, for example. Due to mud etc on the bulbs, it is not possible to obtain total elimination of all pathogens, but a 75% reduction is commonly achieved on tulip bulbs with this technique. “
Damian VanDijk of CleanLight continued: “A processing line for pears, looks beautifully clean and neat compared to a processing line for flowerbulbs. No mud on the product. So, we went to work with high expectations in terms of results. We have installed two “UV Hoods” at a respected Dutch processor of pears, so that all the pears roll under the UV light, thus exposing the entire surface of each pear. And then we asked a well known ag-lab, Groen Agro Control, to take tests, so as to determine efficacy. “
Michel Witmer from Groen Agro Control: “Initially those tests gave confusing results. We had to find the cause for this. Several tests revealed that the UV light itself worked well, but that the brushes where the pears roll on were a source of re-contamination. After all, germs that are inside these brushes can develop quickly in that warm and humid environment, and can not reached by the light”.
Witmer continued: “Another challenge on this project was that in many trials the pears were already clean before being treated. Then the lab report gave the same values as without UV light. That in itself was of course correct, but was not very useful for the grower “
After these challenges were resolved, the results are now plainly good. The appendix contains an example of a test in which the disease pressure decreased by factor of log 2 (more than 90%). Arne Aiking of CleanLight: “That is exactly what we want to achieve for our customers: Not only for flower bulbs, potatoes, and vegetables, but also for hard fruit. With this method the fruit is ideally suited for export to countries with strict standards in terms of pathogens and also in terms of MRL.”