Shellfish, Typhoid, and Private Control of Disease

By Jeffrey Miron.

"According to a recent study, early 20^th c. London fishmongers provided a creative solution for the problem of foodborne typhoid transmission (the study says "Industry-led efforts to mitigate contaminated shellfish reduced typhoid deaths in London from about 1.5 to 0.1 per 10,000 people between 1900 and 1920").

The issue was that shellfish

acted as vectors for waterborne diseases … Once the connection was understood, consumers alone could have substantially reduced typhoid deaths by consuming far fewer shellfish.

Instead, a prominent fishmonger company

used the Billingsgate [fish] market to help high-quality sellers signal the quality of their products by sampling and testing harvest sites, banning sales from known contaminated areas, and requiring vendors to purchase shellfish cleaning services.

This strategy meant that

consumers who were willing to risk their own quality control could purchase shellfish for a lower price from traders who did not transit through Billingsgate, while those willing to pay a premium for third-party quality control purchased shellfish through Billingsgate.

Profit-motivated companies can create public goods."