Typhoid Contamination and Self-Regulation of London’s Shellfish Industry

Our research argues that the mortality rate initially plateaued rather than decreased due to a lack of information about shellfish quality. British consumers have historically been fond of consuming shellfish and other seafood, such as eels. Around 1880, shellfish in Britain were harvested close to the coast in estuaries, tidal flats, and nearshore zones, often after importing young oysters and fattening them on coastal beds. These beds were usually near urban areas and their wastewater discharges. This was dangerous because shellfish near wastewater are noxious for human consumption. Shellfish feed by filtering large volumes of water, accumulating pathogens, toxins, and pollutants from contaminated environments, including human waste. Shellfish near cities acted as vectors for waterborne diseases, and as cities grew (partly because water treatment facilities made them more livable), the problem of contaminated shellfish worsened. At the same time, shellfish became cheaper in British cities as transportation improved and shipping costs fell.

Before the mid-1890s, foodborne transmission of typhoid was not well understood. Initially, the medical community considered milk the main culprit, but in 1895, attention shifted to shellfish. By the early 1890s, the American and British public became aware of the connection between wastewater, shellfish, and typhoid and began changing their consumption choices.

Once the connection was understood, consumers alone could have substantially reduced typhoid deaths by consuming far fewer shellfish, but this would have decimated the shellfish industry. This decimation did not occur; rather, an institutional intervention maintained consumption and reduced typhoid deaths. The response did not come from the government but from industry-led efforts. Most prominently, the Worshipful Company of Fishmongers (WCF) stepped in to secure a substantial and sustained reduction in typhoid mortality while preserving the shellfish industry.

Knowledge of the connection between wastewater, shellfish, and typhoid created the classic “lemons problem” in economics: Consumers were unable to distinguish between high- and low-quality shellfish, so they were unwilling to pay a price high enough to keep high-quality products on the market. This contracted the market and could have led to its collapse without intervention. However, the WCF oversaw London’s central fish market—Billingsgate—and thus had some degree of market power, even though it had long lost its legalized monopoly over London’s retail fish trade. The WCF used the Billingsgate 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. Self-regulation through Billingsgate allowed the shellfish market to become segmented by quality: 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 (or retailers who sourced from Billingsgate). This prevented the lemons problem and the collapse of the shellfish market, and typhoid deaths in London fell from about 1.5 to 0.1 per 10,000 people between 1900 and 1920. The WCF was the primary source of quality regulation for shellfish markets serving London and other parts of Britain for over 30 years. The company provided a model of best practice for subsequent legislation and continues to inspect food quality at the Billingsgate market today.

Note
This research brief is based on Vincent Geloso and Nicola Tynan, “Typhoid Contamination and Self-Regulation of London’s Shellfish Industry,” Social Science Research Network, June 25, 2025.