How urban agriculture improves produce shelf life

What Shortens Produce Shelf Life

If you've ever had a home garden, you've probably noticed that the fruits and vegetables you grow seem to last a lot longer than the ones you buy at the grocery store. Likewise, produce from farmers' markets tends to last a lot longer. What causes this discrepancy?

#1 - Time Spent in Transit

It's a simple equation: (shelf life of a product) - (time in transit from farm to market) = (time until that product will go bad). While that's not the whole story, it is a good starting point. If we look at this equation alone, the most basic way to improve produce shelf life is to make sure it spends less time in transit. Yet many of our favorite foods travel across the globe to get to us, even if they're the same types of foods that we once grew locally.

The concept of "food miles" has gotten a lot of attention lately. The truth is, many foods in your local grocery store traveled across the country or from the other side of the world to be there. Yet local foods offer better shelf lives and often better quality, along with the benefit of far fewer fossil fuels burned in transit.

#2 - Ethylene Exposure

One silent crop killer that many people don't know about is ethylene. The truth is that ethylene gas (C2H4) is naturally occurring, odorless, and colorless. Many fruits and vegetables produce it as they mature and ripen. Unfortunately, it also triggers other fruits and vegetables to ripen more quickly, significantly cutting back their shelf lives. 

Imagine a whole warehouse full of produce that contains a few crates of bananas that are getting overly ripe. The bananas begin to produce ethylene in increasing amounts, spreading the gas through the air to other nearby crops. Before you know it, the cauliflower and cabbage stored nearby also begin to go bad. And so it spreads throughout the facility. Potatoes start to sprout, broccoli yellows, carrots become bitter, and on and on. This chain reaction only grows worse as more crops begin to release their own ethylene into the air. For this reason, produce warehouse managers must implement ethylene control systems, but even these are not perfect.

#3 - Temperature Changes and Extremes

Fruits and vegetables last longest when they are stored at lower temperatures with high humidity. This prevents ripening and keeps decay, bacteria, and yeast at bay. Stored crops should always be kept at a fairly constant temperature to ensure they remain fresh and contaminant-free. The temperature fluctuations that can occur in the transport and storage process can cause products to age more quickly and promote the growth of dangerous mold spores and bacteria.

#4 - Bruising and Physical Harm

Finally, the more fruits and vegetables are handled, the more likely they will suffer physical harm. Jostling occurs quite regularly in shipping and can cause damage that leads to decay and rot. Even the vibrations of the vehicle in transit can be enough to cause harm. This bruising can cause moisture loss by as much as 400%, according to a study from the ATTRA Sustainable Agriculture Program.

Urban Agriculture Helps to Solve These Problems

The world is becoming increasingly urbanized. More and more people are moving to large cities, far from the rural fields where food is traditionally grown. This only increases the need to transport goods from great distances, simply to feed the growing population. Unfortunately, long-distance transportation dramatically cuts down the shelf life of fresh fruits and vegetables, leading to increased food waste.

Urban agriculture offers many benefits, not the least of which is the ability to produce fresh fruits and vegetables locally instead of trucking them across the country or around the world. Less time between the farm and the consumer also means less chance of bruising, less exposure to temperature changes, and less chance for ethylene to build up in storage. In short, food grows near where it will be consumed, so it lasts far longer.

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Source: Eden Green