Abstract: New strains of non-lactose fermenting Pediococcus pentosaceus containing a naturally occurring plasmid are described. The new Pediococcus pentosaceus strains have been exposed to a mutagenic agent, preferably 1-methyl-3-nitro-1-nitrosoguanidine, to modify genetic material which controls the fermentation of lactose to lactic acid. The naturally occurring plasmid is between about 30 to 35 megadaltons in molecular weight. Compositions including the new strains of lactose negative Pediococcus pentosaceus are useful for food fermentations, particularly meat formulations.