Grand Rapids, Michigan, small fruit regional report – September 11, 2012

Harvest season is coming to an end and there are problems associated with the presence of spotted wing Drosophila in ready-to-eat berries.

Spotted wing Drosophila in fruit is a quality issue rather than a human health hazard. So far, there is no evidence that the presence of insects on fruit or vegetables is a human health hazard. It is a quality issue that could interfere with the grower’s ability to sell the produce.

The small fruit harvest season is ending very soon. Blueberry harvest has concluded almost everywhere with only a few fields still harvesting the remnants of late season varieties. At this moment, fall raspberries are the main small fruit being harvested across central Michigan, and a few strawberry fields with day-neutral varieties.

Blueberries, raspberries and other cane berries are having major issues related to the presence of spotted wing Drosophila (SWD) in most fields. This is a serious problem that has increased with time. The presence of SWD infestations is a great concern for growers with late season varieties. As the season progressed, populations of SWD have increased exponentially, making it very difficult to control. Until the middle of August, SWD infestations were observed only in blueberry fields and in a few blackberries. However, at the end of August, infestations have exploited in raspberries and, more recently, in day-neutral strawberries. Last week, we had the first reports of fruit roots in strawberries caused by SWD infestations. Also, for the first time, customers of u-pick operations are complaining about the presence of SWD maggots in the fruit they purchased. This has created some concerns among growers and customers about the safety of the fruit being harvested.

It is important to reassure both growers and consumers that insects are naturally occurring organisms commonly found in harvested fruits and vegetables. In fact, the FDA (Food and Drug Administration) recognizes that fly larvae can be an unavoidable hazard in certain berry products. For example, it has established a Defect Action Level of 4 larvae per 500 grams for canned or frozen raspberries and blackberries. Only products containing larvae at levels greater than the Defect Action Level are considered to be adulterated. The FDA has not established Defect Action Levels for insect larvae in blueberries or strawberries.

In summary, the presence of SWD is a quality issue that could interfere with the grower’s ability to sell the produce or obtain a GAP (good agricultural practices) certification, but not a human health hazard.

Read more information on the FDA Defect Action Levels.

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