The Science of Double-Dipping: How Many Bacteria Does It Transfer to Shared Dips?

We've all done it: taking a bite of a chip, then dipping it back into the shared sauce. But just how much bacteria does double-dipping introduce?

Before Dipping

In a controlled study, researchers tested three popular combinations—chips with cheese, chips with salsa, and fruit with chocolate. Importantly, all dips started with zero detectable bacteria.

Read also: 'Annemiek's recipe: sweet chili sauce'

After Double-Dipping

Participants then double-dipped: biting first, then submerging again. Post-dipping tests revealed 1,000 bacteria in the salsa, 200 in the cheese, and 158 in the chocolate. Encouragingly, after two hours, bacteria levels dropped significantly—especially in the salsa.

Something worth considering next time you reach for that communal dip...