I just harvested some scallions from the garden, where it's getting bit chilly (late November in Seattle).
After chopping them, I realized that their insides were covered in a gelatinous, slippery, viscous goo!
What is it? Is it safe to eat?
Normally, people associate slime with "inedible" because some bacterial colonies can build up slime on spoiled food. But there are plants which naturally produce slime, and it is as edible as any other part of the same plant. Slimes are most common in algae, but I have also seen them in other plants such as hyacinth greens, and scallions have it too, although in normally not that much. But if you mash a "dry" scallion or the greens of a typical yellow onion, they still feel slimy, while other alliums become slimy on cooking, for example leeks.
Physically, slime is just a special kind of gel. As long as it is not of bacterial origin, it is not a sign of spoilage, and it is highly improbable that a living green plant without signs of sickness will be full of colonies of spoilage bacteria. So, I would declare it good to eat.
I have no idea what is actually inside the gel but I believe it to be plant derived. FYI The gel is on the inside of the plant NOT growing on the outside. I have been eating it forever because it is packed with green onion flavor! It's rare that green onions in the store have this gel because they are often more on the dehydrated side in my opinion or perhaps they are grown not to be so jelly because consumers might find it weird. I look at the gel as a delicacy and tend to use the gooier parts for cooking rather than the drier shaft if the recipe calls for limited quantities of green onions. I am perfectly fine. Not even have I turned a shade of green :-P
Another example that I can use for the seattle-ite is you know when you cut a fresh Washington state onion and it produces that white milk upon the first slice? It's the juices from the onion which is very juicy cause its fresh. You don't always see this with other onions because they are probably not that fresh even though they are perfectly edible and flavorful. Hope this helps!
I have bin a chef for 35 years & have never seen slime like this on any of the thousands of green onion i have prepared until today .& anyone that tells me this is normal is lying,slime has bin & always will be a sign that the food is not eatable . In my opinion this is another product of food engineering (AKA: G.M.O) & that is something that no one in the world should be consuming or ingesting & should be avoided at all cost we should eating vegetables that are naturally grown in organic gardens & not this poison the big companies call food