Buyers of fruit, particularly apples and pears, place strict requirements on hygiene standards. Yet at the same time, producers are commonly confronted with stringent residue standards (MRL) concerning chemicals that could have initially prevented the growth germs. This is where CleanLight, a Netherlands-based technology company which uses a handheld light to kill parasites on plants, comes in. CleanLight says its technique is a clean and effective way to protect and strengthen against unwanted pathogens and help fruit exporters meet strict safety regulations.
The company is looking into whether its disinfection technique, known from the cultivation of flower bulbs, would also be effective on hard fruit.
Maarten van Eijk, CleanLight, says: “In the flower industry, disinfecting with ultraviolet light (UV) is already used frequently to combat germs such as Fusarium on the bulbs of tulip, for example. Due to soil on the bulbs, it is not always possible to obtain total elimination of all pathogens, but a 75 percent reduction is commonly achieved on tulip bulbs with this technique.”
“A processing line for pears looks beautifully clean and neat compared to a processing line for flower bulbs. So, we went to work with high expectations regarding results. We have installed two UV Hoods at a 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 agricultural lab, Groen Agro Control, to take tests, in order to determine efficacy,” Damian van Dijk from CleanLight explains.
“Initially, these tests gave confusing results,” says Michel Witmer, Groen Agro Control. “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 cannot be reached by the light.”
“Another challenge on this project was that in many trials the pears were already clean before being treated,” Witmer continues. “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.”
Arne Aiking, CEO of CleanLight, says: “To us, these findings were not very surprising. We also obtained similar results in 2005.”
However, to some important players in the food industry these findings were indeed surprising, he notes.
“This is why we think it is beneficial for the industry if these findings are published,” Aiking reveals.
Fruit and vegetables throughout Europe are generally very safe already, even without this treatment, he explains.
“The risk for producers lies in the fact that they may not meet the very strict contract specifications with regards to hygiene. If they fail that test, their produce has become more or less worthless. So, we assist growers of fresh produce, such as cucumbers, tomatoes, peppers, strawberries and so on.”
According to Aiking, the food industry does not like taking risks with the health of their customers and with their own reputation in the market. Therefore, the industry sets, understandably, strict specifications on their producers with regards to safeguarding food, he notes.
“After these challenges were resolved, the results are now in good stead. The appendix contains an example of a test in which the disease pressure decreased by a factor of log two (more than 90 percent),” notes Witmer.
“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 regarding MRL,” Aiking concludes
