Toxicity model

When producing a food products like our probiotic yoghurt it is very important to verify that the product isn’t harmful to the consumer. Our characterization and kinetic modeling of p-coumaric acid demonstrates that our probiotic bacteria can produce healthy molecules in quantities in the same order of magnitude that can be found in natural products. But it is also of greatest importance that you do not get too much of the good stuff and produce these molecules in very high quantities that could be harmful to humans. To assure that this is not the case in our probiotic food products we have used the LD50 (lethal dose 50 %) values of our healthy molecules and estimated how much of our yoghurt product you would have to drink before reaching harmful quantities.

LD50 comparison

Table 1 shows the LD50 values of three of our healthy molecules in rat and mouse. Calculations of how much a person can drink of our yoghurt product before reaching the LD50 concentration were done by the following formula:

  • V=m(human)*LD50/(Concentration in yoghurt)

  • The mass of a human is assumed to be 80 kg.

  • Table 2 shows some references substances that is readily eaten by most people.

  • Table 1. LD50 of probiotic health substances

    Name of substance oral LD50 [mg/kg] Estimated maximum concentration in yoghurt+ [g/100g] How much yoghurt a 80 kg human can drink before reaching LD50 concentration [L] Comment
    p-coumaric acid 2850[1] (mouse) 0.162[2] 141 Assuming all tyrosine in whole milk is converted to p-coumaric acid
    Resveratrol 3450 [3] (mouse) 0.162 [2] 170 Assuming all tyrosine in whole milk is converted to resveratrol
    Zeaxanthin 2000 [4] (rat) <0.1 >200 LD50 is for a mix of lutein and zeaxanthin

    Table 2. LD50 of reference substances readily eaten by humans.

    Reference substance name oral LD50 [mg/kg]
    Sucrose 29700 [5] (rat)
    Tyrosine 5110 [6] (rat)
    acetylsalicylic acid (aspirin) 250 [7] (mouse)

    This comparison shows that our probiotic yoghurt is not poisonous in any way since you have to drink abnormal quantities to reach the harmful LD50 levels. In the case of p-coumaric acid and resveratrol the LD50 is only twice as big as the substrate;tyrosine. It is then relatively safe to say that if the tyrosine in the substrate does not harm you, the p-coumaric acid or resveratrol in the product fermented on this substrate is safe as well. So relax and enjoy our healthy yoghurt, as we have shown it is good for you!


    1. United States National Library of Medicine. p-Coumaric Acid [Internet]. Available from:

    2. Agricultural Research Service United States Department of Agriculture. Milk, buttermilk, fluid, whole [Internet]. Available from:

    3. Cayman Chemicals. Safety Data Sheet Trans-Resveratrol-d4 [Internet]. Available from:

    4. Ravikrishnan R, Rusia S, Ilamurugan G, Salunkhe U, Deshpande J, Shankaranarayanan J, et al. Safety assessment of lutein and zeaxanthin (LutemaxTM 2020): Subchronic toxicity and mutagenicity studies. Food and Chemical Toxicology. 2011 Nov;49(11):2841–8.

    5. United States National Library of Medicine. Sucrose [Internet]. Available from:

    6. Merck. 108378 L-Tyrosine [Internet]. Available from:

    7. United States National Library of Medicine. Aspirin [Internet]. Available from: