Survival of Lactobacillus acidophilus, Lactobacillus paracasei subsp. paracasei, Lactobacillus rhamnosus, Bifidobacterium animalis and Propionibacterium in cheese-based dips and the suitability of dips as effective carriers of probiotic bacteria

Abstract

The suitability of cheese-based dips as a delivery vehicle for probiotic bacteria including Lactobacillus acidophilus, Lactobacillus paracasei subsp. paracasei, Lactobacillus rhamnosus, Bifidobacterium animalis, and Propionibacterium freudenreichii subsp. shermanii was studied by evaluating the survival of these organisms in dips. Effects of organic acids, oils and gums, l-cysteine and NaHCO3 on the survival of probiotics in cheese-based dips were also studied. Eight different combinations and five individual bacteria as controls of these probiotic bacteria were added to 21 batches of French onion dip and selective enumeration of these probiotic bacteria was carried out over a period of 10 weeks of storage. The population of L. acidophilus and B. animalis reduced by 1 log and 2 log per g, respectively. However, when the inoculation level of these bacteria were increased to 8 log per g, they maintained a population of more than 6 log over the shelf life. L. paracasei subsp. paracasei and L. rhamnosus remained at the inoculated level or increased slightly during the storage. A rapid increase in the population of P. freudenreichii subsp. shermanii occurred to attain more than the inoculation level following reduction in their number by 3 log. Except bacterial interaction, no other factors showed significant effect on the survival of individual probiotic bacteria. Each of L. acidophilus, B. animalis, L. paracasei subsp. paracasei, and L. rhamnosus showed varied levels of antogonism, while P. freudenreichii subsp. shermanii showed no effect. Any combination of these bacteria can be used as probiotics in cheese-based French onion dip. However, the inoculation level should be 8 log per g for L. acidophilus and B. animalis and 7 log per g for L. paracasei subsp. paracasei, and/or L. rhamnosus to obtain greater than 6 log of individual bacterial population at the end of shelf life.