Feasibility of Sanitizing Apple Field Bins to Eliminate Postharvest Pathogens 2000
Project Leader: David A. Rosenberger, Cornells Hudson Valley Laboratory, Highland, NY
1. Evaluate effectiveness of sodium hypochlorite and quaternary ammonia compounds for eliminating P. expansum from apple field bins.
2. Determine if temperature of the treatment solution affects efficacy of sanitizing solutions.
3. Compare wood and plastic field bins to determine if (a) one type of bin carries more inoculum than the other and (b) if one type of bin can be more easily sanitized than the other.
New York State produces approximately 26 million bushels of apples each year. Apples harvested in autumn are held in low-oxygen storage for up to 10 months to allow orderly marketing of the crop and to provide consumers with a year-round supply of high-quality fruit. However, several fungal pathogens can cause apples to decay during storage. In the early 1970s, fungicides became available that prevented postharvest decays in apples. By the mid-1990s, these fungicides had lost effectiveness because the fungi had become resistant to fungicides. No new fungicides have been approved for controlling postharvest decays. In some cases, as much as 15% of the apples held in long-term storage are decayed when apples are removed from storage. Furthermore, spores from decayed fruit spread to sound fruit during the packing process. These spores can cause decays in packed fruit after the fruit is shipped to retail stores. In a survey during winter/spring of 2000, decayed Empire apples were evident in bagged apple displays in nearly 40% of retail stores surveyed.
Previous research has shown that fungal spores can be carried from season to season on the large bins that are used to hold fruit during storage. Sanitizing bins after they are emptied might break the disease cycle, thereby reducing both losses in apple storages and the incidence of decays in bagged apples at the retail level. Research conducted under this project has shown that newer plastic bins harbor large numbers of spores even though the contamination may be less visible than on wooden bins. Therefore, simply switching to plastic storage bins will not resolve the problem. As part of this project, procedures have been developed for comparing commercial sanitizers for effectiveness using small, uniformly-contaminated pieces of wood and plastic bin materials. The next step is to identify the most effective sanitizers and application methods. The final step will be implementing bin sanitation in commercial packinghouses.