These anaerobic bacteria breakdown proteins as the start to digestion, and produce these sulfur compounds as a by-product. Certain conditions cause these bacteria to produce these VSC at an unusually rapid rate. Types of foods may include dairy products especially if you are lactose intolerant and certain foods high in protein. Numerous antibiotics or sulfa-drugs upset the balance of bacterial flora causing some to proliferate and others to perish. An important factor in bacterial growth is the pH of the mouth.
Bacteria reproduce faster in a more acid environment.
Coffee and acidic foods increase acidity. Hormonal changes have even been implicated with bad breath. During menstruation, estrogen causes sloughing of body lining tissue including that of the mouth. This gives additional nutrition for anaerobic bacteria. We all have a different tongue morphology.