SYSTEMS-BASED APPROACH TO ENHANCE QUALITY, SAFETY, AND SHELF LIFE OF ORGANIC TREE FRUIT IN THE PACIFIC NORTHWEST

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: NEW
• Funding Source: OTHER GRANTS
• Reporting Frequency: Annual
• Accession No.: 1026806
• Grant No.: 2021-51300-34913
• Project No.: WNP00867
• Proposal No.: 2021-02949
• Program Code: 113.A
• Project Start Date: Sep 1, 2021
• Project End Date: Aug 31, 2025
• Grant Year: 2021

Project Director
Amiri, A.

Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001

Performing Department
Plant Pathology

Non Technical Summary
Washington State provides nearly all organic pome fruit grown in the USA with an estimated annual farm gate value of a half billion dollars. There are currently 30,000 certified organic acres of pome fruit in the state and it is expected to reach 38,000 by 2022. This quickly expanding organic industry was possible under the dry climate of central WA which keeps disease pressure low and enhanced fruit quality. However, postharvest stakeholders lack effective tactics to maintain quality, safety, and mitigate postharvest decays which combined can results in annual crop loss up to 35%. This integrated and interdisciplinary project aims to bridge pre and postharvest practices and develop a systems approach to address critical challenges by: 1) developing effective and timely preharvest organic sprays to limit fruit infections by postharvest pathogens and define adequate harvest window for enhanced postharvest fruit quality, 2) assessing non-chemical methods, i.e. thermotherapy and dynamic controlled atmosphere, to extend fruit quality, reduce disorders and contaminations by fungal pathogens and human pathogens in storage, and 3) evaluate the efficacy and feasibility of safer anti-microbial and anti-fungal coatings in mitigating human and decays pathogens in cold storage and retail stores. Economic feasibility of proposed approaches will be assessed, and a strong outreach program will ensure effective technology transfer to large and underrepresented organic stakeholders in the PNW and other growing regions. The long-term goal of this project is to support resilience of quickly expanding industry to meet increasing consumer demand for safe and high-quality fresh produces

Animal Health Component

0%

Research Effort Categories

Basic

30%

Applied

50%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1110	1102	40%
205	1110	1020	30%
503	1110	1150	30%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 205 - Plant Management Systems; 503 - Quality Maintenance in Storing and Marketing Food Products;

Subject Of Investigation
1110 - Apple;

Field Of Science
1102 - Mycology; 1020 - Physiology; 1150 - Toxicology;

Keywords

organic

apple

diseases

non-chemical control

postharvest

quality

safety

thermotherapy

Goals / Objectives
Pome fruit growers and packers lack sustainable solutions that fit organic guidelines to grow, store, and pack fruit safely and efficiently. The long-term goals of this project are to empower organic pome fruit stakeholders with novel and more effective approaches to reduce fungal decays, physiological disorders, and human pathogen contaminations. Specefic objectives are:1- Conduct on-farm research to assess the efficacy of enhanced preharvest management practices to fight fungal infections and improve fruit quality in storage2- Conduct lab- and postharvest-research to assess efficacy of non-chemical methods to improve quality and reduce fungal decays3- Assess the efficacy of postharvest organic antimicrobial coatings to mitigate microbial and fungal contaminations in organic fruit4- Develop and deliver outreach activities to organic stakeholders

Project Methods
Activity 1.1. On-farm assessment of new organic materials to implement a timely effective seasonal spray to mitigate fruit infections by field pathogens. We propose to expand our previous study by conducting trials in organic-certified farms to develop a timely spray program based on the epidemiology of major diseases and using the most effective organic materials selected from our recent work. The four most effective materials will be selected and applied in two commercial orchards planted to the cultivar Honeycrisp, a high value cultivar and one of the most susceptible cultivars to many postharvest pathogens and disorders. If our suggested spray program(s) are found to be effective on this cultivar, recommendations will easily apply to other less susceptible cultivars with minor adjustments. Same spray program trials will be conducted at two commercial orchards: Godwin orchard in north WA (Tonasket) and BZBlackrock orchard in south WA (Moxee). The rationale is to test proposed management program(s) on a larger commercial scale in different environmental conditions to ensure final recommendations fit the needs of most stakeholders. At each site, a one-acre organic block will be divided into 2 sub-blocks. One sub-block will be sprayed following the current "standard" grower spray (0-7 days preharvest) and the second sub-block will be sprayed using our proposed "timely" program of 4 sprays throughout the season, i.e., at petal fall, fruitlet, green fruit, and 3 days preharvest. Each sub-block will be divided into 4 smaller sub-block replicates with an equal number of trees. Products will be provided to the cooperators who will apply them using the standard spray equipment (air-blast) that they use in their orchards. At commercial maturity, fruit from each sub-block will be harvested separately by the cooperators in collaboration with PD-Amiri and his team. Two sets of fruit will be collected at harvest to assess the efficacy of the spray programs.Activity 1.2. Effects of preharvest applications of organic ethylene blockers to extend the harvest window and postharvest quality in long-term storage. Organic formulated AVG will be applied at different doses and timings before harvest in two-organically-certified commercial orchards (Stemilt-cooperator) in central WA. We will use randomized complete block design with 10 trees per block, 3 blocks per plot. Fruit (20 per block) will be sampled 25 days before harvest every 7 and 3 days to assess maturity progression by measuring flesh firmness, soluble solids content (refractometer), starch degradation, titratable acidity (malic acid equivalent), skin color (using a colorimeter and subjectively as % coverage), ethylene production (gas chromatographer), respiration (O2and CO2meter), and chlorophyll degradation (index of absorbance differences [IAD] using DA meter). Fruit maturity and quality, including incidence and severity of physiological disorders and diseases, will be evaluated at harvest and postharvest after storing the fruit in regular RA, CA, and DCA at 0-1°C. After 2, 4, and 8 months of storage, 60 fruit per replicate block will be used to measure maturity indices and physiological disorder incidence and severity after 1 and 7 days at 20°C to simulate shelf life.Treatment differences will be assessed using analysis of variance (P<0.05) and mean separation with Tukey test (P<0.05). For non-parametric data,the Kruskal-Wallis ANOVA test will be used to assess treatment differences and Dunn's test for mean separation.These results will be used to assess the economic benefits (Obj. 4) of AVG applications.Sub-Obj. 2.1. Impact of regular and dynamic controlled atmospheres on life of organic fruit and fighting fungal infections in storage.Activity 2.1.1. Effect of dynamic controlled atmosphere (DCA) on fruit quality and physiological disorders [Torres, Year 2 & 3]. Honeycrisp and Gala apples will be picked from two commercial organic orchards and stored in RA, CA (O2 and CO2 set points appropriate for the cultivar), and DCA using respiratory quotient based on initial O2 level at 1°C or 3 °C depending on the cultivar. All these storage regimes will be set at the fruit handling building at TFREC; DCA system will be managed using LabPods (Storage Control System, MI, USA) (Fig. 4). Fruit maturity variables (flesh firmness, soluble solids content, starch degradation, titratable acidity, skin color, ethylene production, respiration, and chlorophyll degradation) and presence of physiological disorders will be evaluated after 3, 4, 6, and 8 months of storage plus 1 and 7 days at 20 °C to mimic shelf life and complete cold-chain scenarios (retail stores). One hundred fruits per replicate and time-point postharvest will be used for these measurements. Treatment differences will be assessed using ANOVA (P<0.05) and mean separation using Tukey's test (HSD, P<0.05). For non-parametric data Kruskal-Wallis ANOVA test will be used to assess treatment differences and Dunn's test for mean separation. These results will be used to assess the economic benefits of DCA (Obj. 4).Activity 2.1.2.1-Efficacy of DCA against four major postharvest pathogens on artificially inoculated detached fruit (Year 1-2). Trials conducted in the 2019-20 season have shown potential of DCA (O2 = 1.5%, CO2 = 0.8%) to reduce decay incidence of four major postharvest pathogen in comparison to regular CA (O2 = 4%, CO2 = 0.8%) and RA (Fig. 3) although differences were not always significant. In Year 1 and 2 of this project, we plan to optimize DCA systems by testing different concentrations of O2 and CO2 until decay is reduced to the minimum without affecting the fruit quality. Herein, we will focus on 4 major postharvest pathogens: B. cinerea, Neofabraea perennans, P. expansum and M. piriformis. For the first two pathogens, Gala apples will be inoculated, while on the trees, with spore suspensions at 500,000 spores/ml 15 days prior to harvest to mimic pre-harvest infections. For P. expansum and M. piriformis, which infect fruit mainly at and after harvest, Gala apples picked at commercial maturity, will be surface disinfected in sodium hypochlorite, rinsed with sterile water, and inoculated with spore suspensions of each pathogen at 500,000 spores/ml. Four replicates of 25 fruit each (total of 100 fruit/treatment) previously randomized using a randomized complete block design (RCB) design will be used. Fruit will be stored in RA, CA, and DCA. For RA treatment, fruit will be incubated in regular cold rooms at TFREC. For CA and DCA treatments, LabPods containers will be used since TFREC does not possess cold room with CA or DCA capabilities. The LabPods (Fig. 4) will be stored in the same cold room used for RA to ensure similar temperature and humidity. Decay incidence and severity (lesion diameter) will be determined after 2, 4, 6 and 8 months of storage and data will be subjected to a one-way ANOVA analysis with the treatments being the variables and means will be separated with Student's t-test at p value ≤ 0.05.

Progress 09/01/22 to 08/31/23

Outputs
Target Audience:PD Amiri has provided talks to an audience of organic pome fruit growers and packers estimated at 400 stakeholders in 2022. Co-PD Sallato has reached out to 25 apple growers of south-central WA to update them about pre and postharvest management and surveyed 10 organic stakeholders for current practices in pre and postharvest organic fruit systems. Co-PD Torres has reached out and trained Hispanic Orchard Employees in March 2023. Changes/Problems:Activity 3.1.1. Some phytotoxicity was observed on fruit while doing the trial. We'll have to redo the trial, reajust concentrations and application methods. What opportunities for training and professional development has the project provided?Training: Sadat Amankona, "Optimization of organic apple storage", Ph.D. in Horticulture. Aug 2022 - present. Professional Development One grower meeting to 25 apple growers. One summer intern conducting a survey to producers Tour and technical discussion. Hispanic Orchard Employee Education Program (HOEEP)- Wenatchee Valley College (39 attendees, 03/08/2023). How have the results been disseminated to communities of interest?Talks: Amiri. A. 202.2. Update on efficacy of numerous organic materials for postharvest rots control. WA State Fruit Association Annual Meeting, Wenatchee. Dec. 06, 2022. Amiri, A. 2023. Pre and postharvest disease management in organic apple systems. WA Apple Review Day. January 25, 2023. Amiri, A. 2023. Effective use of organic materials: preharvest for postharvest diseases. Organic Growers Meeting. Benton City, Feb. 15, 2023. Grower meeting, February 23rd. Columbia Basin Tree Fruit Club (25 attendees) Torres, C.A. 2023. "Impact of hot weather on postharvest fruit quality in apple and pear". ASHS Webinar Series (Feb. 8, 2023). Torres, C.A. 2023. Defectos de Pre-Post Cosecha en Manzanas Asociados a Altas Temperaturas en el Campo. G.S. Long Company, Inc. Grower Meeting, Yakima, WA (Jan 11, 2023). Martha Sanchez-Tamayo, Critzer, F. 2023. Technical presentation. "Inactivation of Foodborne Pathogens on Apples through Application of Antimicrobial Waxes" (ID# 31329) at International Association for Food Protection - IAFP - Annual Meeting. July 16-19, 2023. Toronto, Ontario, Canada. Martha Sanchez-Tamayo, Critzer, F. 2023. Departmental seminar. "Inactivation of Foodborne Pathogens on Fruits by Application of Antimicrobial Coatings". Spring Seminar Series. Department of Food Science and Technology. University of Georgia. February 28, 2023. What do you plan to do during the next reporting period to accomplish the goals?PD-Amiri: Objective 1: Activity 1.1. Conduct on farm assessment of new organic materials Objective 2: Activity 2.1.2. Repeat trials on efficacy of DCA in reducing postharvest decays Objective 2: Activity 2.2.1. Determine temperature thresholds on fruit and their efficacy in inhibiting spore germination Objective 3: Activity 3.1.1. Optimization of antimicrobial coating to fight postharvest decays. Co-PD Torres: Objective 2: Activity 2.2.1. Data analysis for season 2021-2022 and storage trial for 2022-2023. Fruit will be sourced from the same commercial blocks for Gala and Honeycrisp apples used the previous season. This execution of this activity will last 12 months. Objective 3: Activity 3.1.1. Fruit maturity, physiological disorders, and phytotoxicity will be evaluated at the time of treatment (oil-based coatings) and after 3 months of storage at 2°C. Co-PD Critzer: Sub-obj. 3.1. Activity 3.1.2. Evaluate coatings to control foodborne pathogens surrogates in long-term controlled atmosphere storage Sub-obj. 3.2. Activity 3.2.1. Sensory evaluation of antimicrobial waxes on Honeycrisp apples Co-PD Gallardo (Objective 4) Activity 1: Preliminary partial budget analysis of alternative preharvest schedule of chemical sprays (using data from Obj. 1) to derive the net change in farm profit relative to standard practice. Activity 2: Preliminary partial budget analysis of CA and DCA (using data from Obj. 2) to derive the net change in farm profit relative to status quo storage protocols for organic Gala and organic Honeycrisp apples. Co-PD Sallato (Objective 5). Coordinate advisory board meeting (Nov 2023). Grower meeting coordination to deliver outcomes. Translation of outputs to Spanish

Impacts
What was accomplished under these goals? Objective 1: Conduct on-farm research to assess the efficacy of enhanced preharvest management practices to fight fungal infections and improve fruit quality in storage [Research] Activity 1.1. On-farm assessment of new organic materials to implement a timely effective seasonal spray to mitigate fruit infections by field pathogens. [Amiri]. Trials were conducted in 2023 at two organic certified commercial orchards to assess the efficacy of preharvest sprays applied at different timings during the growing season. Trials were conducted on Honeycrisp and Fuji cultivars two of the major cultivars grown in WA. Fruit will be harvested from different treatments in September and October 2023 and will be stored in regular cold atmosphere. Fruit will be inspected for decay incidence and decay type for 6 to 8 months. Data will be available in 2024 and trials will be reconducted then. Activity 1.2. Effects of preharvest applications of organic ethylene blockers to extend the harvest window and postharvest quality in long-term storage.[Torres]. All applications and evaluations were done as planned. Major outcomes include: AVG - organic formulations (Retain®OL) were able to significantly delay fruit maturity (softening, de-greening, starch degradation and decrease in acidity) prior harvest and extend the harvest window. In general, all AVG treatments (different dose and times of application) were able to maintain higher firmness, less chlorophyll degradation, ethylene production and respiration rate until 9 months into cold storage (controlled atmosphere) compared to the untreated control, although not always statistically different at different evaluation time points, including the shelf-life period. Fruit condition varied upon treatments and time in storage. OBJECTIVE 2: Conduct lab- and postharvest-research to assess efficacy of non-chemical methods to improve quality and reduce fungal decays [Research]. Sub-objective 2.1. Activity 2.1.1. Effect of DCA on fruit quality and physiological disorders [Torres]. In 2022, fruit from 3 commercial blocks (2 Honeycrisp, 1 Gala) were harvested and stored in DCA (Dynamic Control Atmosphere), static controlled atmosphere, and regular atmosphere (air) at 3oC and 1oC, respectively. Fruit was stored for up to 9 months plus 4 weeks in air storage. Evaluations of fruit quality and condition are ongoing. Maturity progression in Honeycrisp from both commercial blocks (W42 and C802) showed that due to the growing season weather, particularly the cold spring and heat waves in June and July, increased fruit's maturity rate leading to high ethylene, softening rate and starch degradation at commercial harvest. Activity 2.1.2.-Efficacy of DCA against four major postharvest pathogens on artificially inoculated detached fruit (Year 1-2). [Amiri]. Organic apples harvested in October 2022 were inoculated with spore suspensions at 105 spores/ml of four major postharvest pathogens, i.e., Penicillium expansum, Botrytis cinerea, Phacidiopycnis washingtonensis and Mucor piriformis. Fruit were then stored under three storage conditions, i.e., regular atmosphere, static controlled atmosphere and dynamic controlled atmosphere. Four replicates of 25 fruit each were used for each pathogen and storage condition combination. Fruit will be inspected for decay incidence in August 2023 to mimic long-term storage. Sub-objective 2.2. Activity 2.2.1 Optimal temperatures for apple cultivars [Amiri]. Seven of the most grown cultivars in WA were tested at 5 different temperatures, i.e., room temperature, 48, 49, 50 and 52C for 1 or 2 min to assess temperature thresholds. Preliminary results showed that all cultivars did not show any visible damage when treated at temperatures up to 51C, whereas 2 cultivars showed slight surface browning when treated at 52C. Internal fruit quality is being assessed to evaluate the effect of different temperatures on fruit quality. The same temperatures and exposure times have been tested against 2 major pathogens decaying pome fruit to assess kill-threshold for each pathogen. Work is ongoing to test 3 additional pathogens in vitro. Activity 2.2.2. Efficacy of thermotherapy to reduce postharvest decay [Amiri]. Organic fruit from the cultivar Fuji have been inoculated with spore suspensions of Penicillium expansum, Botrytis cinerea, Phacidiopycnis washingtonensis or Mucor piriformis and incubated for 24 hrs at room temperature. Fruit were then dipped in water at room temperature or in water heated to 50 and 51C. Fruit were incubated at 1C in regular atmosphere and are awaiting inspection for decay incidence. OBJECTIVE 3: Assess the efficacy of postharvest organic antimicrobial coatings to mitigate microbial and fungal contaminations in organic fruit Activity 3.1.1. [Amiri]. Four microbial organic coatings have been tested on detached fruit for their efficacy to reduce storage infection to fungal pathogens. Fruit were stored in regular cold storage and inspected monthly for decay development. There were differences in coatings efficacy but some phytotoxicity was observed on fruit with some of coastings as well. Activity 3.1.2 Evaluation of coatings to control foodborne pathogen surrogates in long term storage [Critzer] Sub-obj. 3.1. Efficacy of antimicrobial coatings applied at harvest to protect from fungal contaminants in long term storage Gala apples Inactivation of L. monocytogenes on organic Gala apples by application of antimicrobial waxes Inactivation of Salmonella on organic Gala apples by application of antimicrobial waxes 3. Inactivation of E. coli O157:H7 on organic Gala apples by application of antimicrobial waxes 4. Sensory evaluation. A sensory discrimination test was used to identify differences between waxed apples for treatments with the greatest efficacy High-level findings: Carnauba wax containing 2% EOs was the most effective treatment for inactivating target foodborne pathogens inoculated on apples for 40 days. This treatment showed 4.05, 1.38, and 2.81 Log CFU/apple reduction in L. monocytogenes, E. coli O157:H7, and Salmonella, respectively, compared to uncoated apples. Carnauba wax containing 2% EOs showed significantly (P<0.001) lower populations of L. monocytogenes and Salmonella compared with 1% EOs, 0.5% cultured dextrose, or wax-only control. In contrast, there were no significant differences (P>0.05) for E. coli O157:H7. Sensory evaluation showed that panelists could detect differences for apples treated with wax containing 2% EOs, but not for 1% EOs compared to wax-only control. Some panelists associated sweet, floral, spiced, and tropical smells as the dominant odors for these samples but did not necessarily find them unpleasant. Honeycrisp apples Inactivation of L. monocytogenes on organic Honeycrisp apples by application of antimicrobial waxes Inactivation of E. coli O157:H7 on organic Honeycrisp apples by application of antimicrobial waxes (in progress - Ends July 2023) OBJECTIVE 4: Economic analysis. Data about returns and costs of production have been collected for organic Gala and organic Honeycrisp. These data are used to develop the enterprise budgets. [Gallardo]. Enterprise budgets for organic Gala and organic Honeycrisp based on industry standard have been updated and published. These will be used as baseline for the economic analysis of the alternatives of preharvest schedule of sprays and postharvest CA and DCA storage treatments to reduce decay and disorders.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Amiri A., Fomba J. 2022. In vitro activity of several organic materials against major postharvest pathogens. Phytopathology 112-11-S3:116
• Type: Other Status: Published Year Published: 2022 Citation: " Gallardo, R.K. and S.P. Galinato. 2022 Cost Estimates of Establishing, Producing and Packing Organic Gala Apples in Washington. Washington State University Extension Publication TB19E.
• Type: Other Status: Published Year Published: 2022 Citation: " Gallardo, R.K. and S.P. Galinato. 2022 Cost Estimates of Establishing, Producing and Packing Organic Honeycrisp Apples in Washington. Washington State University Extension Publication TB91E.

Progress 09/01/21 to 08/31/22

Outputs
Target Audience:Our main audience were organic apple growers and packers. Efforts included: 1-Research: PD-Amiri and Co-PD Torres have worked closely with organic growers and packers to conduct activities planned in Objectives 1 and 2. 2-Outreach and education: A. The team held an Advisory Board meeting in July 2022 to discuss project findings and receive feedback. B. CO-PD Gallardo has reached out to several organic growers to collect data about returns and costs of production for organic Gala and organic Honeycrisp. These data will be used to develop the enterprise budgets. C. Co-PD Sallato conducted a baseline survey of organic apple growers and results were shared with Advisory board members. Changes/Problems:Changes None currently Problems 1-Copping with weather conditions: Severe weather conditions, i.e., snow and freezing temperatures, which occurred just at the bloom period had disastrous consequences on many growers including our collaborators which impacted and delayed some activities in Objective 1. 2-Hiring skilled workers and students. The Covid-19 pandemic has reduced our ability to hire skilled employees and limited student hires, especially international students. 3-Obtaining needed information from stakeholders: Objective 4. Economic assessment The main challenge for the economics study is identifying and reaching out to sources of data for the economic analysis, i.e., meet with at least two organic Gala and organic Honeycrisp growers to validate assumptions and estimates, meet with packinghouse representatives. To address this challenge, we will request from project team members a referral to these stakeholders whom they are working with currently or they have collaborated in their previous projects. What opportunities for training and professional development has the project provided?Training: 1- Janis Fomba, a Scientific Assistant in the Plant pathology program (PD-Amiri) was trained in postharvest pathology and organic decay management. 2- Martha Tamayo, a Postdoctoral Scientist in the Food Science program (co-PD Critzer) was trained in foodborne and food safety issues of pome fruit. Professional Development Janis Fomba attended the 2022 Annual American Phytopathological Society (Plant Health) in Pittsburgh, PA and presented a poster summarizing some of the results from this project. How have the results been disseminated to communities of interest?Workshop: PD Amiri organized a webinar on organic decay management in March 2022 attended by 110 people. Talks: PD Amiri A gave a talk: Update on efficacy of organic materials and research needs to minimize decay at theWA Tree Fruit Association Annual meeting. Dec 7th, 2021, attended by 130 stakeholders. Co-PD Torres gave a talk at the 10th Annual Pace Postharvest Academy, "Storage Technologies for organic apples," Pace International LLC, Clee Elum, United States of America. (May 4, 2022). What do you plan to do during the next reporting period to accomplish the goals?PD-Amiri: Objective 1: Activity 1.1. Conduct on farm assessment of new organic materials Objective 2: Activity 2.1.2. Repeat trials on efficacy of DCA in reducing postharvest decays Objective 2: Activity 2.2.1. Determine temperature thresholds on fruit and their efficacy in inhibiting spore germination Objective 3: Activity 3.1.1. Optimization of antimicrobial coating to fight postharvest decays. Co-PD Torres: Objective 1: Activity 1.2. Repeat preharvest sprays of organic materials to block ethylene Objective 2: Activity 2.2.1. Effect of DCA on fruit quality Objective 3: Activity 3.1.1. Efficacy of antimicrobial coating in extending shelf life of organic apples. Co-PD Critzer: Sub-obj. 3.1. Efficacy of antimicrobial coatings applied at harvest to protect fungal and human pathogens in long-term storage Activity 3.1.2. Evaluation of coatings to control foodborne pathogen surrogates in long-term controlled atmosphere storage Co-PD Gallardo (Objective 4) We will finalize the organic Gala and organic Honeycrisp enterprise budgets. We will also collect data for the partial budget analysis of alternative practices in pre-harvest spraying and in storage to mitigate decay and disorder incidence. Co-PD Sallato (Ojective 5) Co-PD Sallato and all team members will present preliminary findings at grower meetings in WA.

Impacts
What was accomplished under these goals? Impacts: Research findings from this project will impact organic growers and packers in Washington which provide nearly 100% of organic apples to the U.S. consumers. Findings will impact organic apple growers and packers in any other growing regions. This cross-disciplinary project will impact the way organic fruit are grown and stored. This includes empowering organic growers to protect fruit from fungal infections and allow organic packers reduce fruit loss due to postharvest decay significantly. Research proposed herein will also develop solutions to help organic growers and packers to enhance fruit quality (horticultural practices) and extend shelf life of organic apples while reducing physiological disorders. Teh food safety part of the project will help organic packers eliminate foodborne bacterial contaminations in organic apples. Accomplished activities in 2021-2022 period: Objective 1: Conduct on-farm research to assess the efficacy of enhanced preharvest management practices to fight fungal infections and improve fruit quality in storage [Research] Activity 1.1. On-farm assessment of new organic materials to implement a timely effective seasonal spray to mitigate fruit infections by field pathogens. This activity was not conducted in 2022 at organic commercial farms because of severe weather conditions of snow and freezing temperatures which occurred in main production areas of WA state during the bloom period. This had severe consequences on yield. The collaborating growers preferred to postpone this activity to the next season. Activity 1.2. Effects of preharvest applications of organic ethylene blockers to extend the harvest window and postharvest quality in long-term storage.Organic formulation of aminoethoxyvinylglycine (AVG, Retain®OL) was applied at two different rates 166 and 333 gal/ac at three preharvest timings, i.e., 21, 7, and 3 days preharvest (dph) in August 2021 at aa organically certified commercial orchard. Maturity progression was determined using maturity indices (skin color, starch degradation, ethylene production, respiration rate, soluble solids, fruit weight) weekly starting approximately one week before first treatment application. Results: Retain®OL applications were able delay chlorophyll degradation, starch degradation, and softening rate preharvest in a dose and timing-dependent manner. Postharvest evaluations were recently finished, and data are being analyzed. OBJECTIVE 2: Conduct lab- and postharvest-research to assess efficacy of non-chemical methods to improve quality and reduce fungal decays [Research]. Activity 2.1.2.1-Efficacy of DCA against four major postharvest pathogens on artificially inoculated detached fruit (Year 1-2). Fuji apples were inoculated with 10^5 spores/ ml ofB. cinerea, Neofabraea perennans 15 days preharvest or with P. expansum and M. piriformis at commercial maturity. Fruit were stored at 3 different atmospheres, i.e., regular atmosphere (21% O2), Controlled Atmosphere (CA: 4%O2 & 1% CO2), or Dynamic controlled atmosphere (DCA: 0.5 to 0.7% O2, 0.7 to 1% CO2) for up to 6 months. Preliminary results show that DCA reduces decay incidence by 5 to 10% more compared to CA. Experiments will be conducted again in 2022. OBJECTIVE 3: Assess the efficacy of postharvest organic antimicrobial coatings to mitigate microbial and fungal contaminations in organic fruit Sub-obj. 3.2. Efficacy of antimicrobial waxes applied during packing that can be used to protect against foodborne pathogens during distribution to the consumer. 3.2.1. Optimization of carnauba wax to inactivate human foodborne pathogens. Organic Gala apples from WA were treated 2 Carnauba wax concentrations in combination with 4 antimicrobial essential oils and inoculated with Listeria monocytogenes (548-072, ATCC 19115 4b, 19111, Scott A, 1/2a), Salmonella (Gaminara, Montevideo, Newport, St. Paul, Agona), or Shiga-toxigenic Escherichia coli to test for their survival on apple fruit. 1- Survival of Listeria monocytogenes on organic Gala apples. Carnauba wax with 2% EOs significantly decreased (P<0.05) the population of L. monocytogenes during storage at 20°C compared to the other target formulations. After day 30 of storage, no significant differences were found in the L. monocytogenes population for apples treated with carnauba wax with 1% EOs, 0.5% EOs or MicroGARD and apples treated only with carnauba wax. At the end of storage, the population of L. monocytogenes on apples coated with 2% of essential oils was decreased by 1.82 and 4.05 Log CFU/Apple compared with wax treatment only and control treatment (untreated) respectively. L. monocytogenes can survive on the surface of untreated apples over 40 days of commercial retail storage conditions (20°C). 2. Survival of Salmonella on organic Gala apples. Carnauba wax with antimicrobials (2% EOs, 1%EOs, and MicroGARD) significantly decrease (P<0.05) the Salmonella population in apples compared to controls (wax only and no treatment). Carnauba wax with 2% EOs achieves the greatest decrease in the Salmonella population in apples during 14 days of storage at 20°C OBJECTIVE 4: Economic analysis. Data about returns and costs of production have been collected for organic Gala and organic Honeycrisp. These data are used to develop the enterprise budgets. OBJECTIVE 5: Develop and deliver outreach activities to organic stakeholders [Extension]. A team meeting was organized in May 2022, and an Advisory board meeting in July 2022. We conducted a base line survey to organic apple growers.

Publications

• Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2022 Citation: Achour A. and Fomba J. 2022. Efficacy of organic materials against several postharvest pathogens of pome fruit. Abstract. Phytopathology. Accepted