The Survival of the Probiotic Lactobacillus acidophilus in a Model Stomach System

Overview

Objectives/Goals This project tested the viability of the probiotic Lactobacillus acidophilus in the acidic environment of the stomach using an in vitro stomach model consisting of artificial gastric juice maintained in an anaerobic environment at 35oC. L.acidophilus was incubated in the model and samples were taken at time points reflective of minimal stomach transit. MRS agar plates were inoculated with the L. acidophilus samples and colonies counted at 2-11 days. As a control L. acidophilus was incubated in deionized water under the same conditions. Methods/Materials MRS Agar (Remel) Tomato juice, yeast, milk medium and L. acidophilus (Carolina Biological) Artificial gastric juice (Carolina Biological) Anaerobic chamber with GasPak (Fisher Sci.) L. acidophilus capsules (Sprouts) Tums Results Data from experimental incubations in the stomach model with the probiotic L. acidophilus capsules shown in Figure 10 were analyzed using a 2-tailed unpaired t-test. Data is not shown from the time zero incubation, because there were no colony counts recorded for any of the data groups. Results indicate significantly increased colony counts at 30 and 60 minutes for capsules incubated in deionized water with and without Tums compared to gastric juice with and without Tums as well as gastric juice without pepsin (p<0.05). No significantly higher values were observed with any of the incubations containing gastric juice alone or with either Tums or in the absence of pepsin. Conclusions/Discussion Conclusions L. acidophilus delivered as a capsule or liquid culture lost significant viability as measured by colony growth after incubation in an in vitro stomach model. This data supports the original hypothesis for this project. When L. acidophilus was co-formulated with the antacid it was found that there was a no statistically significant improvement in the viability. This data, along with other probiotic research, hints that the viability of bacteria may not be the real reason that probiotics show significant health benefits. Recommendations

Awards (1)

• Honorable Mention

Competition history

• CSEF 2015 Microbiology (General) · Entry S1506

Resources

• CSEF project summary ↗

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