Apple Storage and Washing Effects on Patulin Levels in Apple Cider

In the past two issues of this newsletter, a recent research report in the Journal of Food Protection has been reviewed. The report presented information on how apple quality, storage and washing treatments affected patulin levels in apple cider. The following information highlights the effects of apple storage and washing on patulin levels in apple cider from that report.

Tree picked apples of several cultivars were put in cold storage (0 to 2° C) for four to six weeks. Controlled Atmosphere (CA) apples were also obtained from a commercial storage. After storage, apples were divided into two groups, culled and not culled. Batches that were not culled contained apples with visible damage and mould (this also included bird pecks, skin breaks, hail damage or major bruising).

Patulin was not detected when apples were culled prior to pressing but was found in five of the seven cultivars in cider pressed from unculled fruit. Data in this study indicates that although fungal growth is reduced at temperatures less than 10° C, the growth of P. expansum and the production of toxin are not prevented during cold storage.

Patulin levels in cider pressed from CA stored unculled apples (three trials) were found to be greater than 59 ppb, while in two trials of cider pressed from CA fruit that had been culled had no patulin detected. The third trial found 15.1 ppb of patulin.

The overall results indicate that culling is an important method to reduce patulin levels in cider made from cold or CA stored fruit. Stringent culling procedures are needed to keep patulin levels to a minimum in cider pressed from stored fruit.

Batches of ground harvested golden delicious apples (not culled) containing different patulin levels were given one of three treatments prior to pressing: (1) no wash, (2) a chlorine solution wash (100 or 200 ppm), or (3) a potable water wash. Washing treatments reduced the patulin levels in cider by 10 to 100% depending on the initial patulin level and the type of wash solution used. No significant difference was found in patulin levels for cider made from apples washed with 100 or 200 ppm chlorine solutions. Two trials did not show chlorine solutions to be more effective than water in removing patulin from contaminated apples. This study, along with other work highlighted, indicates that wash treatments cannot ensure that patulin levels are below the 50 ppb action level established by regulatory agencies.

For detailed report information and supporting documentation refer to the Journal of Food Protection, Vol. 66, No. 4, 2003, Pages 618-624

"Apple Quality, Storage, and Washing Treatments Affect Patulin Levels in Apple Cider" by Lauren S Jackson, Tina Beachham-Bowden, Susanne E Keller, Chaitali Adhikari, Kirk T. Taylor, Stewart J. Chirtel and Robert I. Merker