Just the facts. From the experts.

Recently, we interviewed Dr. Floyd Woods and Dr. Joe Kemble, both from Auburn University, about fruits and vegetables. These experts offer some excellent advice about storage and shelf life, in addition to their expertise about washing fruits and vegetables.

  Dr. Floyd Woods

Dr. Joe Kemble

 

The fridge is too cold for some fruits and vegetables. Don't store tomatoes in the fridge. It's too cold in there! Most refrigerators are set around 35°F to 45°F which is too cold to store tomatoes and many other vegetables such as summer squash, bell peppers and eggplants.     

Watch for chilling injury. Most fruits (oranges, lemons, etc.) and vegetables (tomatoes, peppers, eggplants, cucumbers, watermelons, etc.) of tropical and subtropical origin may be damaged by cool temperatures and develop a condition called chilling injury. Chilling injury results from prolonged exposure to low but not freezing temperatures. Symptoms of chilling injury include dark circular pits on the surface, shriveling, internal darkening, loss of the ability to ripen and the development of off-flavor and poor texture.

Each fruit and vegetable has its own shelf-life. Depending on the fruit or vegetable, the shelf life can differ from a few days after it is harvested to one or two weeks (months for many winter squashes, Irish potatoes, pears, apples and root crops) depending on how the produce is treated after it is harvested. If this is produce that you purchased from a supermarket or farmers market, you might not be able to do much to extend its shelf-life unless you know when it was picked and how it has been stored. 

Proper berry storage will help achieve a maximum post-harvest life. In the case of strawberries, blueberries and other berries, generally any wetting or direct contact with water is detrimental and will shorten their shelf-life. You should never place any of these into your sink to soak them. Before you store them, be sure that they are clean but do not wash them until you are ready to use them. Strawberries, blackberries, blueberries, and raspberries are natives of temperate climate and can be stored in your refrigerator. In fact, they should be stored as close to 32°F as possible to maintain their shelf-life. When stored properly, strawberries have a shelf-life of a week, blueberries can last up to two weeks, and blackberries and raspberries will last two to four days.

If you cool the produce from your garden correctly, then you will extend its shelf-life. As an example, if you are going to cool and sanitize your tomatoes you will need to do more than simply run the fruit under cold tap water. In fact, that is the worst thing you can do. You will need to dip or soak your tomatoes in water that is the temperature of the tomatoes that you just picked. So if it is 85°F outside, the internal temperature of your fruit will be about 85°F. When preparing your cleaning solution, the water must be at the same temperature as the tomato. We realize that this seems odd, but if the water is cooler than the fruit the drastic change in temperature will cause the tomato to actually draw in or suck in through its pores water that surrounds it. It is a great way to get microorganisms into your tomatoes that will ultimately cause a fruit rot. After you clean and sanitize your tomatoes, place them in a cool area somewhere around 55°F.

 

Have you ever washed fruits or vegetables in a mixture of water and vinegar? A Facebook post says to fill a sink with water, add 1 cup of vinegar and stir. Then, soak the fruit for 10 minutes and it will sparkle with no wax or white, dirty film. The post claims this will also make produce last longer.

Last year, we asked Julie Albrecht, PhD, RD, about the best way to wash fruits and vegetables. To follow up, we wanted to know if vinegar really helps clean them. Dr. Floyd Woods and Dr. Joe Kemble answered questions about washing produce in vinegar. 

To summarize their answers below:

  • Is it safe to soak fruits and vegetables in the sink with water and one cup of vinegar?
    • Yes, but the extent and effectiveness of sanitation by using vinegar will depend on what you're trying to clean.
  • Will washing with vinegar really help get the fruits/veggies clean?
    • Yes, but the concentration has to be high enough. Research has shown that a 3 part water to 1 part vinegar is most effective. Consider using a product specifically formulated for cleaning produce. Taking all of this into account, the use of a vinegar is not necessary if you simply wash your fruits and vegetables using fresh, clean water. 
  • Does washing produce in vinegar ensure fruit lasts longer?
    • No. Extending the shelf life of fruits and vegetables involves much more than simply washing or sanitizing. All fruits and vegetables have predictable shelf-lives and in order to optimize these shelf-lives it is important to cool the produce as quickly as possible after it is picked. The use of a vinegar treatment will not, in itself, extend the shelf-life of a fruit or vegetable that was not handled correctly after harvesting.

 

Is it safe to use vinegar or acetic acid to clean produce?

Dr. Floyd Woods and Dr. Joe Kemble: Vinegar or acetic acid is safe to use as a home remedy to clean, sanitize, or surface sterilize a variety of fresh fruits and vegetables. However, the extent and effectiveness of sanitation by using vinegar will depend on the nature of the suspected disease-causing agent(s). In other words, fungi and bacteria can be effectively removed from these fresh products by using vinegar, but the effectiveness of the vinegar depends on which bacterium and/or fungus is on (or suspected to be on) the fruit or vegetable, the concentration of the vinegar, the temperature of the water, and the amount of time the produce is exposed to the vinegar. 

 

How much vinegar should you use? At what concentration?

Dr. Floyd Woods and Dr. Joe Kemble: The concentration of vinegar that you purchase at the store is lower than most of the commercial formulations designed to sanitize or surface sterilize fresh fruits and vegetables. If you are in doubt as to what to do, your best course of action is to use one of the commercial preparations such as Tsunami (peroxyacetic acid-based sanitizer). Tsunami contains a cousin to acetic acid called peroxyacetic acid and has been used effectively for many years to control post-harvest microorganisms. Since you are not likely to know which microorganisms are on your produce, your safest course of action is to treat for the worst case scenario (which most commercial products do). 

If you decide to use vinegar, research has shown that a 3 part water to 1 part vinegar is most effective. From the photo on Facebook, one cup of vinegar in a sink would not have been enough vinegar to make a difference. Don’t forget to clean your sink before you soak and clean any of your produce. A soak of five to 10 minutes should be sufficient. Try to get the water temperature as close to that of the fruit or vegetable that you wish to clean.  When you have a variety of fruits and vegetables, it might be best to wash these separately. 

 

Is it OK to use water to clean produce?

Dr. Floyd Woods and Dr. Joe Kemble: When it comes down to making an informed choice as to what you should use to clean off fruits and vegetables, research has shown that using just plain old water can remove 98% of the bacteria when it is used to rinse and soak produce. Simply washing produce will remove any bacteria or other residues on your produce. 

Before using any agent to clean, sanitize, or surface sterilize any fruits or vegetables, it is important to remove any soil or debris that might be on the produce. Any organic matter or soil present in the solution will decrease the efficacy of the active ingredient – acetic acid or peroxyacetic acid from the examples above.   

 

Will washing produce in vinegar make it last longer?

Dr. Floyd Woods and Dr. Joe Kemble: As to the extent that vinegar or another similar treatment will prolong post-harvest life of various fruits and vegetables, it depends on the specific fruit or vegetable. Each fruit and vegetable has its own shelf-life, which can differ from a few days after it is harvested to one or two weeks (months for many winter squashes, Irish potatoes, pears, apples and root crops) depending on how the produce is treated after it is harvested. If this is produce that you purchased from a supermarket or farmers market, you might not be able to do much to extend its shelf-life unless you know when it was picked and how it has been stored. 

Resources for more information on ideal storage conditions and methods of cooling your home-grown produce:

 

What about storing and cooling produce from your own garden?

Dr. Floyd Woods and Dr. Joe Kemble: If you cool the produce from your garden correctly, then you will extend its shelf-life. For example, if you are going to cool and sanitize your tomatoes you will need to do more than simply run the fruit under cold tap water. In fact, that is the worst thing you can do. You will need to dip or soak your tomatoes in water that is the temperature of the tomatoes that you just picked. So if it is 85°F outside, the internal temperature of your fruit will be about 85°F. When preparing your cleaning solution, the water must be at the same temperature as the tomato. We realize that this seems odd, but if the water is cooler than the fruit the drastic change in temperature will cause the tomato to actually draw in or suck in through its pores water that surrounds it. It is a great way to get microorganisms into your fruit that will ultimately cause a fruit rot. After you clean and sanitize your fruit, place them in a cool area somewhere around 55°F. With tomatoes, never place them in your refrigerator! It is too cold in there!  Most refrigerators are set around 35°F to 45°F which is too cold to store tomatoes and many other vegetables such as summer squash, bell peppers and eggplants. 

 

So how should you store fruits and vegetables?

Dr. Floyd Woods and Dr. Joe Kemble: Most fruits (oranges, lemons, etc.) and vegetables (tomatoes, peppers, eggplants, cucumbers, watermelons, etc.) of tropical and subtropical origin may be damaged by cool temperatures and develop a condition called chilling injury. Chilling injury results from prolonged exposure to low but not freezing temperatures. Symptoms of chilling injury include dark circular pits on the surface, shriveling, internal darkening, loss of the ability to ripen and the development of off-flavor and poor texture. Proper storage will help achieve a maximum post-harvest life.

In the case of strawberries, blueberries and other berries, generally any wetting or direct contact with water is detrimental and will shorten their shelf-life. You should never place any of these into your sink to soak them. Before you store them, be sure that they are clean but do not wash them until you are ready to use them. Strawberries, blackberries, blueberries, and raspberries are natives of temperate climate and can be stored in your refrigerator. In fact, they should be stored as close to 32°F as possible to maintain their shelf-life. When stored properly, strawberries have a shelf-life of a week, blueberries can last up to two weeks, and blackberries and raspberries will last two to four days. 

- See more at: http://www.bestfoodfacts.org/food-for-thought/fruit-vinegar#sthash.Kl6Q6FTI.dpuf

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