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Ssawg 2019 post harvest handling


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How to ensure the longest storage life for your harvest.

Published in: Food
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Ssawg 2019 post harvest handling

  1. 1. Post Harvest Handling for Maintaining Quality Presented by Michelle Akindiya Farmshare Austin Education Manager
  2. 2. The highest quality is at the moment of harvest. Post harvest techniques should focus on how to maintain that quality.
  3. 3. Four main concerns with post harvest handling: 1. Avoid physical damage & bruising 2. Quickly reduce field temperature 3. Minimize moisture loss and shrinkage 4. Sanitation
  4. 4. First, grow a healthy plant. ● Focus on soil health and nutrient balance ● Proper irrigation ● Disease and pest prevention ● Variety Selection ○ appropriate for the season, your farm’s microclimate and soil type ● Avoid mechanical injury from tractor or hand cultivation ● Trellis when appropriate to keep fruit off the ground Production practices effect harvest quality.
  5. 5. Second, harvest at peak quality ● Some crops can be harvested before they are fully ripe and then ripen by the time they get to market: ○ Tomatoes, cantaloupe, fruit and berries ○ The crop must reach a certain level of maturity (about 75% ripe) before that technique works without sacrificing flavor ● All other produce must be harvested as ripe as the consumer will desire ○ Be aware that the storage length of baby crops is decreased ● When harvested over-ripe, storage time and flavor is compromised
  6. 6. Best practices for harvesting ● Harvest early in the morning while it is cool. In the winter months, wait for things to thaw before harvesting. ● Be gentle. Produce should be seen and not heard. ● Remove jewelry & trim nails before harvesting. Wear gloves, especially when field packing or harvesting items that will not be washed. ● Cull disease and over maturity in the field as much as possible. ● Handle each crop as little as possible ○ field bunch - precount rubber bands or twist ties to keep track of harvest quantity ○ field pack - as much as possible pack in the field items that do not need to be washed ● Use proper tools that are clean and sharp
  7. 7. Harvest Containers ● Use containers with smooth inside surfaces and venting ○ Smooth surfaces are easier to clean and sanitize and will not bruise produce ● Think about storing your containers when not in use. ○ Containers should be foldable, stackable and/or nesting ● Using a standard size helps with planning & projecting yields ● Avoid overpacking containers ○ You don’t want anything getting squished ○ Put heavier crops, like potatoes, in smaller boxes to prevent injury ● Avoid underpacking containers ○ You don’t want product to be able to roll around and get bruised IFCO or RPC
  8. 8. Harvest when dry to prevent spreading disease Better to harvest dry: 1. Nightshades - fungal diseases 2. Cucurbits - fungal diseases 3. Berries - rot and fungal diseases 4. Green beans & peas - rust and powdery mildew 5. Storage roots - you want them to dry out, wash before sale 6. Storage alliums - want to cure & dry - more likely to rot when wet Can be harvested wet a. Greens b. Brassicas c. Sweet corn d. Fresh alliums - green onions e. Fresh roots
  9. 9. Get it COOL! Harvested produce is still alive. It continues to respire - to breath - even after it is harvested Remember, the second a crop is pulled from the ground or removed from the plant, it begins to deteriorate. We can slow down the rate of respiration by getting the crop to the lowest safe temperature as quickly as possible.
  10. 10. ● Carbohydrates break down to CO2 and water ● Both are released from the crop leading to ripening, rotting and dehydration ● Results of Respiration: ○ loss of nutrients ○ drying out ○ weight loss ○ flavor loss - sugars turn to starch ○ loss of value ○ shorter shelf life ○ loss of reputation. Respiration
  11. 11. Temperature reduces respiration rate! The higher the respiration rate of a crop, the more essential it is to get it cool fast and maintain the cold chain in storage and delivery.
  12. 12. Plan for the whole harvest ● Break up into teams ● Plan your harvest to get the crops with higher respiration rates first ● Take everything out with you at once - all the tools, crates, rubber bands, etc. ● Get product back to packshed as soon as possible A good Farm Manager orchestrates efficiency.
  13. 13. Harvest early in the morning when cool ● Keep harvested produce in the shade ○ under trees, in a shaded wagon or truck ○ Can use burlap, old sheets, row cover or shade cloth to create shade ● Can take buckets of water out to the field to harvest into ○ Good for cut flowers or bunches of greens
  14. 14. Cooling Methods Rapid cooling to the coldest safe temperature is essential! Hydro-cool Room Cooling Forced Air Icing
  15. 15. Hydro-Cool Just what it sounds like - dunking the crop in cold water It is more about getting the field heat out than about cleaning the produce, but it can serve both purposes Your packing material must be able to be wet You’ll need vented boxes and/or drying tables Your water basin needs to be able to be sanitized. You may want to add sanitizer to the water.
  16. 16. Room Cooling Also just what it sounds like - produce is simply loaded into a cold room, and cold air is allowed to circulate among the cartons. It takes more time to bring down the temp, but good for crops that don’t want to be wet Best suited for less perishable commodities, such as potatoes, onions, apples, sweet potatoes, and citrus fruits It is important to leave about 1 inch between stacks of boxes inside the refrigerated room in order for the cold air to circulate and cool the boxes evenly Produce in vented boxes will cool much faster than produce packed in un-vented containers.
  17. 17. Ice & Forced Air Icing Quick to cool and keep humidity high, but can be used only with water-tolerant, non- chilling, sensitive products Need water-tolerant packages Need an ice machine Forced air Fans blow air through stacks of produce It is usually expensive and can dry out the produce too much, but is much quicker to cool than room cooling.
  18. 18. Washing & Drying ● If you can, do not wash. ○ Use mulch and trellising to keep things clean in the field ○ Grow more upright varieties ○ Harvest with cotton gloves and dry brush in the field ● When you do wash, use municipal water or treated water ● You may also want to add a sanitizer to the wash water of high risk crops ● Dry well before packing or baging ● Consider equipment to help you save labor on high volume crops ○ Barrel washer ○ Greens bubbler & spinner
  19. 19. Packing & Sorting ● Think like a buyer, not a like a farmer ○ Your reputation is on the line - don’t let anything but the best go out to your customers ○ Customers are long term assets ○ Different customers will have different expectations and wants ● Don’t over or underfill containers ● Use clean containers with no sharp edges, stackable & standard size ● You can use reusable ones, but think about how you get them back and how you sanitize them ● You can line bins with plastic liners to keep in moisture if needed ● Do label and BRAND your products. farmer-training/
  20. 20. Packshed Design ● Efficiency of flow ○ Produce and people ○ Dirty in one side, clean out the other ● Ergonomic ● Easy to clean and sanitize ● Appropriate technology
  21. 21. Storage Each crop has a unique set of requirements to maximize storage time Variables that affect storage time: Temperature Humidity Ethylene Gas Production & Sensitivity
  22. 22. Humidity Loss of water from produce can cause wilting, shriveling or textural changes that can reduce value. Too much water and you will see rots and molds, especially with longer storage crops. You’ll want both a thermometer and hygrometer in your cold rooms Storage crates should be able to drain for excess water, but also be kept covered to keep in humidity.
  23. 23. Chilling Injury Keeping products too cold can also be a serious problem. Many fruiting crops do not like to go below 50 degrees for long periods of time.
  24. 24. Storage Groups LOW HUMIDITY Cold (32 - 36 degrees) Onions & Garlic Warmer (not below 50 degrees) Potatoes, Sweet Potatoes, Winter Squash HIGH HUMIDITY Cold (32 - 36 degrees) Leafy Greens, Fresh Root Crops, Brassicas Warmer (not below 50 degrees) Cucumbers, Summer Squash, Okra, Green Beans, Tomatoes
  25. 25. Ethylene Gas Some crops are highly sensitive to ethylene gas Some are high producers of the gas Keep these two groups separate Have good ventilation in your cold rooms Remove over ripe fruits from cold rooms
  26. 26. Ethylene Groups Ethylene Producers Apples Cantaloupe Pears Ethylene Sensitive: Apples Brassicas Green Beans Carrots Cucumbers Lettuce Parsley Pears Tomatoes Watermelon
  27. 27. Post Harvest Cheat Sheet by Atina Diffley : content/uploads/storage-requirements-for-vegetables.pdf
  28. 28. Cooler Options Coolbots - Used commercial walk ins - check auctions Old refrigerated trucks Old refrigerators Kits Build from scratch - R25 insulation value
  29. 29. Delivery Maintain the cold chain! How are you going to get your products to market safely? Do you need to purchase a refrigerated truck? Many coolers? The answer lies somewhere in your crop list, climate and distance to market.
  30. 30. Resources Small-Scale Postharvest Handling Practices: A Manual for Horticultural Crops (5th Edition) -