No Double‑Dipping Appetizers


I could not believe my eyes. A young man rushes to the restaurant restroom. The only audible splashing is not from water in the sink but against the urinal.

Zipping his trousers while back bumping the exit door, he slides into the booth next to his date. Just in time to share a piping hot order of french fries! Bon appétit.

They Are Not Sanitary


One study suggests that 67% of people wash their hands after visiting the restroom. The CDC estimates just 31% of men wash properly following toilet visits. Each trip to the loo is its own unique germ-infested journey. So some occasions require more post-washing than others. As you can imagine, all those dirty hands infest restaurant menus with 100 times the bacteria as a typical toilet seat.

Take Some and Pass it Down

A sports bar keeps bowls of salty snacks on the counter to stimulate patrons’ thirst. The more beer they drink, the more they empty their bladders—making room for more drinks, and tips. By late evening, how many communal peanuts offer more in their golden coating than salt and oil.

You order a round of guacamole, salsa and chips for sharing with a group of friends. In a conscientious hygienic effort, you pass around a bottle of sanitizing gel. The server prepares fresh guacamole table-side before the salivating guests.

With the air wafting a pungent mix of isopropyl alcohol and cilantro, everyone digs in to the appetizer. Halfway into the guacamole, the dip-bite-dip sequence is sighted across the table. You recall no one leaving for the restroom, but perform a quick head count as confirmation. Are you safe from contamination?

Halfway into the guacamole, the dip-bite-dip sequence is sighted.

The Science of Double Dipping

Double-Dip Etiquette

Double dipping is the introduction of personal germs into a communal food reservoir. It doesn’t matter whether the conduit is a chip, spoon, chopstick or finger.

In a research study, Clemson University food safety professor Paul Dawson, et al. dipped crackers into liquid and viscous solutions. This includes water, acidic water, salsa, cheese dip, and chocolate dip. Five thousand 5000 bacteria per milliliter (PML) transfer through plain water. Acidic water (pH of 6.0) transfers about 3800 bacteria PML.

More bacteria sticks to the chip when double dipping thick consistencies like guacamole or sour cream. Bacteria is most likely to disperse throughout the bowl with thinner dips like salsa.

Each double dipper contributes to the bacteria accumulation. What types of bacteria are we sharing? A healthy mouth contains Streptococcus, Prevotella, Veillonella, and many others. Someone with a common cold or mononucleosis can bring more to the party.

About 100 to 200 species thrive in human oral cavities. With good oral hygiene each tooth surface can host 1,000 to 100,000 bacteria that make up our microbium and aid in digestion. Less hygienic mouths mouths carry 100 million to 1 billion bacteria per tooth. —Oral ecology

Etiquette dictates that there be a serving spoon for each dish. This encourages you to scoop the dip onto your plates for personal use. Are you a double dipper, compulsive etiquette enforcer, or communal-dip avoider?

To support the writing of useful articles about nutrition, ClinicalPosters sells human anatomy charts, scientific posters and other products online. Also shop for ClinicalPins that include more than lapel pins or leave an encourag­ing comment to keep the work going.

Add Your Comment