Probiotics' fate: assessment of the viability of ingested bacterial strains


After consumption, ingested bacteria are exposed to a highly harmful
environment. Low pH, high level of pepsin, bile acids and pancreatin are just a few examples of stressors present in the gastro-intestinal tract. In most human studies the persistence of ingested bacteria in the intestine is quantified by colony counting on agar plates from faecal samples. However, cultivation tends to underestimate bacteria viability and faecal samples don’t give insight about the probiotics’ fate in the upper gastro-intestinal tract.


The project aims to assess the specificity and feasibility of detection and quantification of 3 probiotic strains (Streptococcus thermophilus, Lactobacillus delbruieckii subsp. bulgaricus and Lactobacillus rhamnosus) in human ileostomy effluent samples after fermented milk products ingestion.

The student will:

  • Optimize and validate a viability-quantitative PCR (V-QPCR)
  • Actively participate in a human intervention study in collaboration with Maastricht University


    During this study a mix of both classical and novel microbiology techniques will be
    performed. Culturing bacteria, selective plate, PCR, QPCR, V-QPCR. The student will be given the possibility to travel to Maastricht for the sampling and for the initial handling of samples (all the expenses will be reimbursed).


    Students pursuing MSc/BSc
    degree in Biology, Molecular Life Sciences, Animal Sciences or related
    discipline. Previous experience with molecular methods will be preferred.

    Contact information :

    Edoardo Zaccaria, PhD;