Does sharing a toothpaste tube spread contagious bacteria and germs

A [Limited] study on the microbial flora contamination in tooth paste.



The purpose of the present study is to identify microbial flora present in tooth paste [two top brands which are commonly used by people are chosen as samples for the study.] and the level of contamination upon usage under controlled method and limited samples.

To identify the multiplication of flora on usage at regular intervals and at different phase of time during the life of tooth paste pack.


Two top brands which are commonly used by people are chosen as samples for the study.

The average pack size a 80gms, packed in squeeze tubes were chosen for the study as it was fast moving size in the markets.

A controlled method was chosen to have a uniform method for the study.

About the method:

Paste packs sample A and B are labeled.

This method is adopted by single user for each tooth paste sample.

This method is carried out in good hygienic toilet environment.

The samples were taken for the trials, under controlled exposure. That is the pastes are dispensed in equal quantities for brushing, twice a day. Both the samples are stored under hygienic and equal environmental exposure, the tooth brushes were protected with pest control caps. This method is practiced though the study course to have uniform exposure, equal quantity dispensing method.

This procedure is conducted in limited number and just to identify if there is any contamination and large sample study can not be inferred on this basis.

A swab sample was taken from paste, on the day 1 of the study. The sealed packs were opened under sterile conditions at the laboratory and samples were dispensed to identify the microbial flora. The tests were repeated in intervals of time to estimate the growth of microbes/contamination. Tests were conducted on day 1, day 10, day 15, and day 30th .

Results: Toothpaste sample culture.


Sample A organism isolated

Sample B organism isolated


Aerobic spores grown on culture

No growth observed after 48 hrs incubation.


No growth observed

No growth observed


No growth observed

No growth observed


No growth observed

No growth observed


Aerobic spores were identified in sample A which was on day 1 were in it was company sealed pack, and was opened under sterile conditions in laboratory to dispense the sample for testing before any use.

Upon usage and on later stages of tests the tooth paste samples proved to show no multiplication or any kind of growth.

We can conclude that upon regular usage as in case of the above mentioned conditions the contamination in negative.

Note: This inference is applicable for the above mentioned method and procedures and result might vary under different exposures or conditions.

A work framed and executed by Dr. JAISRI RAJESH BABU ( of personal interest.