When we read the label on a package of probiotics to find out how many CFU’s it contains, we see some rather strange figures that show a number multiplied by 10 which in turn is raised to a number that is usually between 6 and 10. This way of expressing numbers is called “scientific notation” and is used to express very large or very small numbers in a more simplified way than if we had to handle the numbers with all their ten, twelve, fifteen or more digits.
In the case of probiotics, every product we can find for sale usually contains billions of CFU’s of viable cells or microorganisms. As this is therefore a very large number, this “scientific notation” is used to express the amount of probiotics in a more simplified form.
However, when expressing these amounts of CFU’s, two very important factors should be taken into account which may lead to confusion:
1.- Format (figure or text) in which the quantity is expressed
If the value of probiotic microorganisms appears in figures, we use, as we said before, the scientific notation. Thus, the figures indicated on the label could be, as an example, similar to these:
- 12.000 x 106 cfu de Lactobacillus acidophilus
- 40 x 109 cfu de Lactobacillus casei.
In the first case, the figure is equivalent to 12,000,000,000 cfu of Lactobacillus acidophilus and in the second case the equivalence is 40,000,000,000 cfu of Lactobacillus casei.
However, if the information on the probiotic content indicated on the label is written in text rather than using figures (e.g. one million cfu or one billion cfu, etc.) it may lead to confusion as the concept of “billion” is not the same depending on whether the product is manufactured in the European Union or in the United States or the United Kingdom.
In the European Union, 1 “billion” of cfu equals 1,000,000,000,000 cfu but in the UK or the US, 1 “billion” equals 1,000,000,000 cfu, that is 1.000 million “Europeans” or, in other words, 1 European “millard”.
1 billion de cfu (US/UK) = 1 millard in the UE = 1.000.000.000 ufc.
It is important to take into account this difference since depending on the origin of the product we can be talking about 1,000 times more or less microorganisms.
Example of an actual label for a probiotic from a US company: The number of probiotics indicated is 30 Billion, i.e. it is 30.000 million microorganisms and not 30.000.000 million that would be our interpretation if the product were labelled according to the European Union numbering.
2.- Value reference
Sometimes the information we see on the label does not clearly show the amount of probiotics as it may be referred to the recommended daily dose or referred to the pharmaceutical single dose (amount per capsule or tablet).
Probiotic that indicates on its label: “40 billion ferments” but nevertheless each capsule has 10 billion probiotics. What happens here is that the manufacturer recommends a daily dose of 4 capsules, which having each 10,000 million, the daily dose is 40,000 million that indicates on the label but we can be confused because we can interpret that each capsule has 40,000 million and not 10,000. Hence the importance of always reading the information indicated by the manufacturer on its label in detail.
Degree in Pharmacy – Universidad Complutense de Madrid.
Specialist in Chemical Analysis – Universidad Complutense de Madrid.
Master in Pharmaceutical Industry – CESIF Madrid.
Diploma in Ophthalmic Optics – Universidad de Barcelona
Diploma in Optics and Optometry – Universidad de Granada