Lactobacillus F19 has been tested in fermented milk products (Svensson et al, 1999; Fondén et al, 2003). An important consideration was the potential antagonism of Lactobacillus F19 towards starter cultures. Research has shown that F19 had no negative impact on either thermophilic or mesophilic starter cultures. It was found of Lactobacillus F19 towards starter cultures. Research has shown that F19 had no negative impact on either thermophilic or mesophilic starter cultures. It was found that F19 actually improved growth and acid production for some of the tested starters. Results shown in Figure 4 demonstrate that when using F19 as a probiotic culture, the selection  of  compatible  starters can be expanded, utilizing starters that were previously considered less than optimal.
    

As its name implies, Lactobacillus F19 belongs to the group  of bacteria referred to as common food lactobacilli. The bacterium has been found in yellow cheeses made from both pasteurized and raw milks. Lactobacillus F19 can survive and actually grow in cheeses making it an ideal candidate for promoting cheese as a functional food group. In that way, considerable numbers of probiotic bacteria can be delivered to the human intestinal tract  in relatively smaller amounts of food.

F19 is a robust, hardy probiotic strain that has a multiplicity of applications. Viability studies in many different types of foods such as infant cereals, stewed fruit syrups, ice cream, and other dairy products have shown that Lactobacillus F19 survives well. For example, in dry infant cereal, more than 10 million (1 x 10⁷) cfu's of F19 were added per gram of cereal (Figure 5). The functional food was stored at 30^oC (86^oF) for 72 weeks. In that time and at that temperature, cell counts of F19 decreased only 1.5 logs.