The following examples of probiotics in foods shows that a diet rich in fermented or cultured foods will give you an enormous variety of lactic acid bacteria which is the group that almost all of the probiotic bacteria come from. It really isn't necessary to take supplements to benefit from a daily intake of beneficial probiotic bacteria.
For example, when traditional soft white cheese from eight different regions in Morocco was studied they discovered a total of 164 lactic acid bacteria in it. That is the sort of diversity that we USED to eat each day.
In my home country of New Zealand, I'm not likely to find Nigerian ogi on the shelf BUT the local Maori make a "delicacy" (it smells disgusting!) of fermented maize called kanga pirau. By looking at the list below I can see that, chances are, it will be high in L plantarum.
Foods of vegetable or grain origin that are known to contain L plantarum provided they have not been pasteurized or heat treated.
Dairy sources of L plantarum are:
Meat sources of L plantarum
If you believe you need to take Lactobacillus plantarum as a supplement then Allergy Research Group Lactobacillus Plantarum/Rhamnosus/Salivarius contains 10 billion cfu of an unspecified strain of L plantarum.