Leuconostoc bacteria, computer illustration. These are Gram-positive, coccoid, chemoorganoheterotrophic, facultatively anaerobic bacteria (prokaryotes), nonhemolytic, vancomycin resistant, acid-tolerant microorganisms. They are traditionally found in association with plant matter, fermenting vegetables, milk, dairy products, wines and meats. Leuconostoc species are often used in production of fermented foods because of their ability to produce lactic acid and diacetyl. Leuconostoc species can often be found in the wild and are a part of the natural microflora in almost all farming soil. They can cause meningitis, bacteremia, urinary tract and pulmonary infections.