The best i can come up with is putting paper towels in the bag with the lettuce and putting it in an air tight container. But even that doesn’t work too well. What else is there to do.
I have no proof, but I would assume that the act of shredding creates such an increase in surface area that you can only keep it for a short period of time. That is, without preservatives.
Why do you need to shred it and then keep it? For how long?
Produce suppliers now seal packaged bean sprouts and leafy greens in an argon (inert gas) atmosphere. While difficult to implement at home it is highly successful in retarding spoilage.
Are you buying your lettuce pre-shredded? If so, why? You are being charged many dollars per pound for saving you 15-30 seconds of time and energy.
Try purchasing a full head of lettuce. Use a sharp long-bladed knife to cut off thin cross-sections of the lettuce (perpendicular to the stalks). These will fall apart into very nice shreds. The remaining intact head of lettuce will have a shelf life that is nearly ten times longer than its pre-shredded cousin.
Air tight containers are not helping you either. They permit condensation of exuded moisture to collect upon the lettuce, accelerating its spoilage. Try wrapping your lettuce in just the paper towels only. You could put them in a paper bag if you wanted. This might help a little. As pointed out by samclem, increasing the surface area (and cut membranes) of your lettuce by an order of magnitude is not doing you any favors.
Add a teaspoon of lemon juice to the container and shake to distribute over the leaves. The juice acts as an antioxidant and slows browning. Linkydinkydoo for the skeptics.
My grandmother-in-law wraps every leaf in paper towels, and it seems to work. I know this doesn’t answer your question about shredded lettuce, but Zenster had an interesting idea about that.
Otherwise, consider living better through chemistry.
I have always heard that cutting lettuce rather than tearing it hastens browning. I have never tested this scientifically. However, the lemon juice idea is a good one, works for apples.
When it comes down to it, lettuce is fairly perishable and can’t be expected to last too long even under the best of conditions.
I buy it shredded.
"Are you buying your lettuce pre-shredded? "
I do & it keeps for weeks if I don’t open it.
Make sure it is dry, and wrap it in a (clean!) rag and then put the whole thing in a plastic bag in your fridge.
It works for me.
This isn’t very cost effective if you don’t already have one, but I store our leaf lettuce in one of the canisters that comes with the Tilia FoodSaver vacuum sealer. Only my husband eats lettuce in our house, so we were losing about a half a head a week to the compost pile. After we got the vacuum sealer I can use up the whole head and it lasts about 2 weeks. I don’t know how well it will work for shredded, but I do usually just separate the leaves then cram them in all together, if that info helps at all.
Use a plastic knife. You can buy them as they are specifically made for cutting the delish veggie your speaking about! I don’t know why but apparently using a metal knife causes the lettuce to brown more quickly.
good luck!
Although plants take in CO[sub]2[/sub] and give off O[sub]2[/sub] during life, the process can reverse after death, with the sugars reacting with oxygen to produce water and CO[sub]2[/sub]. Lettuce is one of the more slow products in its respiration rate. Shredded respires faster than leaf, for the reasons mentioned above. Wounds and greater exposed surface area contribute greatly, as does temperature.
From the International Fresh-Cut Produce Association:
Keep it VERY cold, and VERY moist. But not below 31 degF, where chill problems can occur.