I often use my food processor to get the food into a small dice. I don't do it to a slurry, that IMO is unnecessary and can heat up. I chop by hand, once again in small chunks sometimes, but more often use the processor.

Then I freeze the food in plastic bags.

Smaller particle sizes definitely decompose faster. It isn't necessary to go to the trouble of grinding food, it will decompose either way, but there is something therapeutic about preparing food for your worms.

I have an old hand-cranked meat grinder that I use to grind up the food before I put it in the bin. Some foods are too soft to go through (potato peels) or too fibrous, so they jam the grinder (onion skins). I have found that if I freeze the food, everything goes through the grinder better. I freeze food scraps and feed about once a week.

If something simply won't go through the grinder, I take the plate off of the grinder (the piece that has the tiny holes you force the meat through). Simply forcing the food through the auger will grind down everything enough for the bacteria to get to it fairly quickly.

My thought is what is the goal? If you are trying to raise worms to sell for bait, or to others form composting, then it's worth the energy usage to chop, grind and generally mascerate the food.

But if your goal is to go green and have some way to get rid of kitchen waste without dumping it into a landfill and generally be eco-friendly, then why bother?

Yes, since worms don't have teeth, smaller particle size will enable the worms to consume larger quantities of food or rather it will be more more available to them. But is it worth the effort or energy expenditure?

My two cents worth:

I don't see the point of grinding an freezing food for worms. It wastes electricity, energy and time. In nature worms aren't getting broken down stuff either, so why should we "pamper" them, as well as adding to our electricity bill. I add the food as it comes off the chopping block. If it went off in the fridge I poke some holes into the skin (for tomatoes or apples) just to make sure the bacteria can get to the inside.

As I said, just my 2c

Hey pryropunk,
My freezer is running anyway, so it's not costing me more to freeze my worm food. I have a lot of food for them, and I like them to eat it as fast as possible.
It's relaxing for me to chop and freeze the food for them. Freezing inhibits fruit flies, which is a major, major bonus for me.

Smaller particles = faster decomposition
Decomposition = microbial feed for worms
Frozen or microwaved food = no viable fruit fly eggs
Frozen or microwaved food = faster decomposition (see above)

Worth it? Up to you.

It seems like there must be 2 groups of thought on this...probably it depends a lot on whether your worm bin is indoors or out.

Having mine indoors, I certainly want to do everything I can to increase the speed of decomposition because 1) the bin is not very big, and I do have a lot of food scraps, so the faster the worms can make it disappear, the faster I can add more scraps, 2) I know that if the food sits too long, it might start to smell, and 3) the faster the food decomposes, the faster I can have worm castings for my garden.

I, too, think it's fun "preparing" scraps for worms (although I don't use a machine to chop it because then I'd have to clean it...) Cleaning would be a waste of time for me, but chopping up kitchen scraps isn't a waste of time IMO, because I consider it a hobby. I sometimes also put extra kitchen waste in the freezer, because as we all know, there is a limit as to how much you can add to an indoor bin. I have a Tupperware container that I keep in the freezer for any extras.

If I had an outdoor bin, I probably would just throw everything in, and forget about it. But since that's not the case for many of us, speed of decomposition is key to a successful indoor worm bin.

I agree with pyro. I put food in the bin the same way it leaves the kitchen or cutting board. If there is an excess, then I freeze it. After that I still just throw it in frozen. If what I put in there is slow to decompose, I know that I can give additional feedings without problems. Some of the harder fruits and root veges sit in there for a couple of weeks not doing anything, but they don't smell. Bacteria that causes it to smell will be quickly swept away. Carrot tops will grow sprouts and potatoes will grow shoots and shrivel up. In the end the sprouts will die and it will all be polished off. Sometimes I don't have anything to feed them. At that point I know that I am eating too much garbage!