Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2008
Publication Date: 7/30/2008
Citation: Janisiewicz, W.J., Saftner, R.A., Conway, W.S., Yoder, K.S. 2008. Control of blue mold decay of apple during commercial controlled atmosphere storage with yeast antagonists and sodium bicarbonate. Postharvest Biology and Technology. 49:374-378. Interpretive Summary: Products containing naturally occurring bacteria or yeasts on fruit have been used commercially in large packinghouses for the control of fruit decay after harvest, but their spectrum of activity is relatively limited. We developed a portable drencher for small orchard operations and conducted a pilot test to control blue mold of apples under commercial conditions using a mixture of beneficial yeasts. The treatment combination greatly reduced blue mold decay on apples after five and a half months of controlled atmosphere storage. This pilot test confirmed our earlier laboratory experiments showing the effectiveness of this treatment combination in reducing blue mold decay on apples.
Technical Abstract: A mixture of two yeast antagonists, Metschnikowia pulcherrima and Cryptococcus laurentii, originally isolated from apples and having superior biocontrol activity against blue mold of apple over individual application of these yeasts, were used in combination with sodium bicarbonate (SBC) in a pilot test under commercial controlled atmosphere (CA) storage conditions. The treatments were applied to apples by drenching the entire bins filled with apples containing 100 wounded fruit in the middle of each bin. The treated fruit were stored in commercial CA storages for almost six months in 2005/2006 and 2006/2007 storage seasons, and then evaluated for incidence of decay. In the 2005/2006 season, most of the decay occurred on a control treatment (P. expansum alone) (27%) followed by SBC (17%), and then antagonist mixture alone (4.3%) or in combination with SBC (0.7%), between which there was no statistical difference. In the 2006/2007 season, the trend was similar but the incidence of decay was higher, most likely, due to inferior storage conditions that resulted in fruit shriveling and low survival of C. laurentii. This pilot test showed that the combination of these two antagonists and SBC can be an effective decay control method under CA commercial conditions, confirming results from our earlier laboratory study under CA conditions.