A starter material isn't technically necessary, though a good amount of some sort of neutral, non-food based material (such as leaves, dirt, etc) will help to keep it from smelling like rotten food.
Otherwise, the natural flora and fauna will breakdown the foods over time, as long as a reasonable nitrogen ratio is maintained.
sustainability.stackexchange.com/users/56/Benjamin Brannon
A starter isn't a requirement, but it can certainly help.
A shovel from a long-standing site of decomposition will work.
Manure works really well in a compost pile that includes food scraps, as it provides thermophillic bacteria that like the stuff we eat.
Include plenty of fine carbonaceous material such as sawdust, to maintain the carbon-nitrogen balance.
Build the compost pile big so it can get hot.
My compost hits 130 degF.
sustainability.stackexchange.com/users/27/Jay Bazuzi
It's more important to worry about a good balance of materials ("greens" and "browns" so that you have about a 30:1 C:N ratio) than it is to worry about a starter colony.
In terms of what to use: you can use existing compost, well-rotted animal manures, or healthy soil from your garden.
All of these things will have the microbe families that you want in your compost pile.
sustainability.stackexchange.com/users/66/bstpierre
A dead mouse in the compost will attract the right kind of microbes.
sustainability.stackexchange.com/users/47/Kristoffer Nolgren
It's not essential, but it will speed up the process initially if you use a good mix.
Personally I don't bother, but I don't really mind when the compost comes and am happy to wait.
If you could do with the compost sooner rather than later, then chuck a load of rich soil or existing composting material in there to get it started - they contain a lot of the necessary bacteria which should thrive on their new found food.
sustainability.stackexchange.com/users/52/berry120
When starting a compost pile from scratch for kitchen food scraps, do I need some kind of starter material?  For example, should I take any material from an established composting pile to seed it with appropriate biological agents?  If needed, is such starter sold in any stores?
Does a compost pile for food scraps need some kind of starter material?
sustainability.stackexchange.com
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sustainability.stackexchange.com/questions/15
sustainability.stackexchange.com/users/20/WilliamKF
A starter material isn't technically necessary, although it might help and speed up the process. A good amount of some sort of neutral, non-food based material (such as leaves, dirt, etc) will help to keep it from smelling like rotten food.  It's more important to worry about a good balance of materials ("greens" and "browns") than it is to worry about a starter colony. A starter can help but is not essential. A balance of green and brown is very useful for composting.
A starter is not essential, though it is helpful. A balance of green and browns is more important than a starter.