New post-harvest technologies help maintain produce quality from field to consumer

By Marni Katz

New post-harvest technologies are helping improve the shelf life and delivery of fresh produce while offering extended marketing windows for commodities, such as apples and sweet onions. Among these are:

  • Food-grade tasteless coatings and films that can help reduce respiration and moisture loss of stored produce;
  • Commodity-specific modified atmosphere packaging (MAP) that puts fresh-cut produce into a state of hibernation to maintain quality;
  • Controlled atmosphere to help reduce respiration during transportation or storage; and
  • New technologies that affect the ethylene production and ultimately maintain quality while reducing shrink for retailers.

New breakthroughs, along with older, well-known technologies, enhance growers and shippers ability to store produce longer and ensure quality deliveries during extended marketing windows. Many also have food safety implications by offering traceable handling and packaging methods while inhibiting the growth of potentially harmful microorganisms.

But experts say that even with this rapid progress in technology, there is still no substitute for careful post-harvest handling. And the two must work in tandem to make the new technologies successful.

Kathy Means, vice president of government affairs for the Produce Marketing Association, says the key benefit of the new technologies is to help deliver a top quality product to consumers that will motivate repeat purchases.

There have been a number of advances in the way produce is handled to enhance shelf life and provide a top quality product to consumers, Means says.

Managing ethylene production

Many of the technologies essentially work by slowing the metabolism and respiration of fresh produce and retarding ripening or decline by managing ethylene.

Ethylene, a hormone produced by a number of commodities, has varying effects, depending on the fruit or vegetable.

It can be beneficial, giving tomatoes their red color, for example. Or it can be detrimental, turning broccoli yellow or carrots bitter. Its role in improving produce storage, either to use its beneficial effects or prevent its detrimental effects, has been studied for decades.

One breakthrough for managing ethylene is a product called SmartFresh. Marketed by Agro-Fresh Inc. in Spring House, Pa., the unique technology essentially works with nature's own ripening process.

When SmartFresh is present, the fruit does not detect naturally produced ethylene, and the negative effects associated with over-ripening are slowed. Once fruit is removed from storage, ripening begins again.

Marita Cantwell, a University of California, Davis, post-harvest physiologist, studied Smart-Fresh for four years and says the product can successfully maintain the quality of ethylene-sensitive crops, such as apples, which are typically stored in controlled atmosphere for extended periods. Cantwell is continuing to look at the benefits of SmartFresh on post-harvest handling of other ethylene-sensitive crops, such as tomatoes, melons, carrots and leafy vegetables.

This is really a new tool in post-harvest handling, and it's quite a spectacular tool in many commodities, Cantwell says. It's exciting, because it does have potential benefits for many produce items. Of course, whether it pans out in terms of logistics of application and cost and benefits for many produce items still needs to be worked out.

Raphael Crawford, vice president of North America sales and marketing for AgroFresh, says SmartFresh applied to apples in CA or RA rooms has produced notable improvements in product quality for the end-user.

Consumer taste tests have confirmed that SmartFresh quality apples are crunchier, juicier and more flavorful, Crawford says.

The company is also working on developing SmartFresh applications for bananas, melons, avocados, tomatoes and pears.

In bananas, for example, SmartFresh can be applied in the ripening room to help the fruit retain its yellow color for up to eight days without turning brown, Crawford says.

At this time, those are the crops where we can have the maximum impact on quality to consumer, he says. Ultimately this technology is about the benefit to the consumer and helping the industry give them the best eating experience possible.

Fresh-cut drives post-harvest technology boom

By using newer technologies and tools to manage ripening and enhance deliveries, growers, shippers and distributors are helping ensure a good eating experience once the produce arrives to the end-user, Means says. The new technologies also have helped expand the market for fresh-cut produce, contributing to a second important consumer motivator in purchasing produce convenience.

Fresh-cut produce now accounts for about 15 percent of total produce sales. This year, it is estimated to be a $10.5 billion segment in the retail and foodservice produce sectors. New MAP packaging is helping extend the shelf life and improve the eating quality for many of these increasingly popular fresh-cut items.

Intelimer Specialty Packaging, marketed by Apio Inc., is just one example of MAP packaging tailor-made to enhance the shelf life of the specific commodity inside. The gas-permeable label adjusts the interior atmosphere based on commodity and temperature, creating the ideal environment to inhibit microorganism metabolic activity and growth, which lead to decline.

Technology only supplements good handling

Chris Watkins, a post-harvest physiologist at Cornell University in Ithaca, N.Y., says demand for high quality is driving much of the new technology in produce storage and handling.

Demand for increasing quality in the marketplace is leading to much improved post-harvest technologies right through the whole system, Watkins says. But a lot of that improvement can be handled at quite simple levels, such as better temperature management, better humidity management, better use of ventilation and attention to products that should or should not be mixed together.

Cantwell says products such as SmartFresh, MAP packaging and other storage technologies can help mitigate the effects of poor handling, such as temperature abuse during distribution, and also maximize the benefits of good handling.

In mixed loads, for example, where it is impossible to meet the ideal temperature and atmosphere requirements of all commodities, the technologies can help prevent negative effects as a result of the compromise.

Still, Cantwell says, temperature management remains the number one step in maintaining post-harvest quality across virtually all commodities.

As a post-harvest physiologist, I would say -the main tool we have is good temperature management, she says. These technologies don't take the place of good handling practices.

When we talk about SmartFresh in apples, we are talking about it as a supplement to doing everything else right, Watkins says. The same factors that affect good storage are improved by a product like SmartFresh, but if you don't do everything else right, it's not going to do as much good. G

For questions or comments, contact Vicky Boyd, editor of The Grower, at (209) 571-0414 or vlboyd@att.net.


10 ways to boost post-harvest quality

Marita Cantwell, a post-harvest physiologist at University of California, Davis, says new technologies to enhance produce storage are only effective when basic principles post-harvest handling are followed. She provides these 10 tips:

1. Maturity: Harvest the product at the correct maturity stage.


2. Reduce injuries: Keep physical handling to a minimum; every time the product is handled, it is damaged.



3. Protect product: Protect the harvested product from the sun; bring it rapidly from the field or exposed area to the packing sta-tion, and keep out of the direct sun. Trans-port carefully.



4. Cleanliness and sanitation: Keep the packing line as simple as possible, and keep it clean. If water is used, use clean water; if the water is reused, use a sanitizer. Maintain strict worker hygiene.



5. Pack carefully: Sort, classify and pack the product carefully to achieve uniformity and prevent damage (compression, scrapes, etc.), which causes decay and inferior qual-ity; use an adequate box or container. Pack-aging can also be informative.



6. Palletize: Ensure that the boxes are well placed on the pallet and that the pallet is strapped.



7. Cool: Cool the product as soon as possible after harvest; generally for every hour of delay from harvest to cooling, one day of shelf-life is lost. Lowering product tem-perature is the most important way to reduce deterioration.



8. Know the product: Know the requirements of the market (size, ripeness, etc.) and the product handling requirements (temperature, relative humidity, shelf life, etc.) of the product.



9. Coordination: Always try to coordinate the post-harvest handling, so it is efficient and rapid. Post-harvest handling maintains the quality of a product, it cannot improve it.



10. Training: Train and compensate the workers involved in critical post-harvest handling steps; make sure workers have the necessary tools to help them.


Internet Hotlink

Information on post-harvest handling and technology can be found

at the University of California, Davis, post-harvest Web site:

http://postharvest.ucdavis.edu