In principle, and as far as I know, the acidification capability of a certain LAB strain mostly depends on its acid resistance so you should look for acid resistant variants. You may find in PubMed a number of papers describing acid resistant LAB strains. However, if you are dealing with poor growth in a food product, the problem is more complex and you must consider other factors. If you could provide some additional data about your problem maybe you can get more help.
i am treating food waste in anaerobic reactor for bio-hydrogen production and i am facing the problem with reactor pH due to accumulation of volatile fatty acids which acidifies the system and become rate limiting step in bio-hydrogen production.