Sunday, September 17, 2006

Ready To Eat? Maybe Not...

With ready-to-eat spinach/E. coli on our minds, I thought it perfect time to figure out just how these pre-washed vegetables maintained their freshness. We eat a lot of bagged, "pre-washed" baby carrots, and I've always wondered why they can sit around in a moist plastic bag and refrain from molding or other forms of rot.

You may (or may not) want to know how they do it... The following contains some data from USDA studies. The main methods of "preserving freshness" (quite an oxymoron) fall into two major categories:

1) Special packaging films with modified atmosphere packaging (MAP) method
2) Cleaning chemicals in the wash

Apparently, fruits and veggies are still "alive" and each item "breathes" at a unique rate. The plastic film's permeability to oxygen and the amount of oxygen/carbon dioxide initially injected into each bag differs depending on the bag's contents. Modified atmosphere packaging (MAP) is a method of "balancing oyxgen and carbon dioxide, which causes the produce to respire slowly." If there is too much oxygen, the product will brown. If it's too low, the product will "prematurely decay."

Here are some chemical agents used to wash cut fruits and veggies. They're mainly used to control microorganism growth - why mold and bacteria don't grow on these delectable looking products - and to preserve the visual appeal of the product ("antibrowning agents" and things that "slow decay").

Acidified sodium chlorite (ASC) - sanitizing agent on cut carrots
Chlorine rinses
PQSL 2.0 - "breakthrough for wash solutions because it not only maintains an apple slice's color, firmness, aroma and flavor, but also reduces levels of Listeria and Salmonella bacteria."
Calcium ascorbate dip – prevents browning on apple slices
1-Methylcyclopropene (1-MCP) - a gas treatment that slows decay, used on apples, tomatoes, avocadoes and more; has been shown to penetrate watermelon rind to prevent degredation, which "can buy extra time for shipping and prolong a product's selling season."

And apparently, manufacturers are warned that "wash solutions lost their antimicrobial activity over time, and should not be reused on multiple batches of produce.” But fear not, "research is underway to find a way to maintain the antimicrobial properties of wash treatments." Yum - A chemical wash that won't loose it's chemical-ness with time.

Let me just say that I have no problem with big business using and developing new methods that will help them stay competitive and earn a profit. Ready-to-eat things are all the rage as people have less time and less inclination to prepare their own foods, and businesses that make these need to be able to offer a product that will look good and sell well. And consumers are partly responsible - you can't have unadulterated fresh fruit that also sits on a shelf without rotting, and the fact that we demand this makes us partly responsible for the evolution (or mutation!) of food industry practices.

The only problem is that I doubt that Joe Schmoe really knows what manufacturers put into his ready-to-eat food, and I believe that he at least has the right to know. That juicy cantaloupe that Joe's about to bite into is deceptively like a fresh-cut cantaloupe, except that it's bewn processed and dipped in some pretty strange materials. And if Joe's OK with that, more power to him - that's Joe's choice. It's just that the Joes of the world should have the option of knowing what's been done with their food.


Anonymous Wild Flower said...

What happened to my comment that I submitted & was posted here a week or two ago? And what happend to ALL of the comments by other people what were posted under this article. Don't invite comments, then delete them or people won't return to your site. Re-post everyone's comments, please, or I'll find a more interactive site to visit.

8:41 AM  
Blogger always learning said...

Wildflower - I'm not sure I know which post and what comments you are referring to. The only comment I've ever received from you has been for this blog entry:

I'm sorry you think that I'm deleting comments... I welcome any and all opinions and would never just randomly decide to delete comments. That said, the number of comments I have deleted since the inception of this blog can be counted on one hand. Most were spam, and one was a very potty-mouthed comment that had little to do with the contents of the post. And you can always tell if comments are deleted by the author because they have this:

"Comment Deleted
This post has been removed by the blog administrator.
10:29 PM "

12:04 PM  
Blogger always learning said...

Also, if you can't find blog entries, that doesn't mean they are not around. For whatever reason, the current blogger setup allows only a certain number of entries on each page. To find entries from before, please see the right hand column, under "archives" and search under "month/year." If you don't see Archives, you can go to the blog's main page ( and they should be there.

12:40 PM  
Anonymous kim said...

Thanks for taking the time to research and post this.

We eat a ton of prepackaged/precut veges and fruit in this house, and I never even thought to question their longevity. And they do last a lot longer than the non-bagged varieties.

Guess I'm back to fresh and/or organic.

Except for spinach.

1:39 PM  
Anonymous Anonymous said...

Chemicals are tasty and useful. I'm a lazy person, so I'd rather take the chemicals over the fresh stuff that immediately rots any day. A little chemicals never hurt anybody (except for maybe cyanide, agent orange, saccharine). What would you rather have though, a slightly increased risk of cancer, or food that you don't have to work as hard to eat?

That being said, if I had a large family and could prepare things without them sitting in the fridge for weeks, then I probably wouldn't be as reliant on the chemically preserved food. As an engineer though, I think the modified atmosphere packaging is genius, and we should all be giving that a thumbs up.


1:23 PM  
Blogger always learning said...

Kim - You're welcome. I was just curious as to why the moist baby carrots rarely went bad, but after reading into how these things are "preserved," I thought others might be interested.

Garrett - You're right. It's extremely hard to cook for one without eating nasty leftovers, or having things go bad. I think your points are well taken, and a good number of people share them, hence the exploding market for ready to eat food. In terms of your list, you'd probably be OK in the short term if you just had a little agent orange exposure. ;P Or even cyanide for that matter (it takes a while to kill in small amounts, doesn't it?). Isn't saccharine still in a lot of the sugar free stuff? I seem to recall the sugar free industry defending it saying that the mice that developed tumors had eaten huge amounts of the stuff, and the relatively small amounts in our food should be harmless... at least in the short term... :)

3:31 PM  
Anonymous Anonymous said...


I'm a writer and an editor, so it's a natural habit of mine to make a copy of everything I write or edit, before and after it’s published. Here's a copy of what I wrote, which was posted on your site on Sept. 21, which someone did, indeed, delete, along with several others' comments... . So, please re-post:
Wild Flower said...
I think this spinach/e-coli outbreak was deliberately set up so that the FDA & drug companies could push the "vital" life-death scare tactic on people so that the public would demand for the virus to be used on our food. Reverse psychology tactic. I can't be fooled. I don't want foreign viruses sprayed on or grown into or put into/onto my food or my dog's food.
10:46 AM (SEPT.21, 2006 @ 12:46 P.M. CENTRAL TIME)

8:12 PM  
Blogger always learning said...

Hi Anon,

I'm glad you have a copy of your comment. I'm not sure if you're getting this post mistaken with the "Would You Like Some Virus With That" post (8/16/06), which you did indeed comment on, and where your comment, and that of others, has always been available. (at least that I can see.. ?) The link is here:

tried to link the web address, but don't know how to do it. you can either cut and paste to find that post, or you can google "wandering visitor would you like some virus with that" and find the same post.

Please check to see if this is the post and comment you are referring to and let me know. Thanks

10:30 PM  
Anonymous Anonymous said...

It's good to know how one's food is processed, but I don't have a problem with food preservation by means of disinfection. Food borne illness is much more of a threat to human health than a hypothetical, one in a million risk of cancer due to a chlorine rinse of baby carrots. Filthy kitchen sponges and lack of handwashing and basic kitchen hygiene are more of a threat than modified atmospheric storage or chemical rinses.

12:43 PM  
Blogger Giordano said...

calcium ascorbate - that would be Vitanmin C neutralised with Calcium. I take a gram of each day.

9:45 PM  

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