In August 1892 the city of Hamburg was hit by one of the last large cholera epidemics in Europe. After an initial phase of ignoring the epidemic despite fatalities, and even issuing health certificates for emigrant ships bound for New York (where the cholera broke out after the arrival of these ships), authorities shifted gear in late August when Robert Koch was sent to Hamburg as representative of the Imperial Government and introduced a strict set of measures to stop the spread of the cholera. These measures included closing the port, closure of schools, prohibition of large assemblies, isolation of the city from its hinterland, and most importantly the provision of clean drinking water. Nevertheless, it took ten weeks before there was a decrease of daily new infections and by then half of the near 17.000 infected had died.
Already some days prior to the outbreak of the cholera in Hamburg, the Reichsamt des Inneren (Department of the Interior) had published a set of official guidelines on how to minimize the spread of cholera and to avoid an epidemic. While it seems that Hamburg authorities ignored these guidelines (at least for the few days before the city was really hit hard), other German cities enacted them immediately and went even further. While the guidelines by the Department of the Interior dealt extensively with drinking water and sewage, they did not include any recommendations on ice, which is after all nothing else than frozen water.
One of the very first cities where ice, and in particular the local ice trade gained the attention of the authorities was Bremen. On March 22nd, 1893 the Bakteriologisches Institut (Bacteriological Institute) was formally opened, some 2 decades after public food and water inspection existed in the city. The original duties of the institute included, among others, ‘control of and advice to ice producing companies’.
Knowing that water was the main suspect for the transmission of the cholera, the institute took samples from ice-deliveries in the city, regardless whether the ice was locally produced or imported. In addition, the institute introduced regulations on which ponds could be used for ice-cutting and which ones should be avoided based on water-quality. They also offered pre-season advice to any company that was interested in cutting natural ice in the area.
Despite these regulations and activities, there were some cases of polluted natural ice when tested in that summer and these cases became the starting point for a discreditation campaign against natural ice that lasted well into the 20th century.
Of course, those companies that had invested in artificial ice production with the help of ice machines had an interest in pushing natural ice out of the market as much as possible. Cholera and other diseases transmitted via water became an ideal tool for such campaigns and the rapid transition from natural to artificial ice demonstrated the success of these campaigns.
Nevertheless, the one and only reason for the pollution of the ice was pollution of the water prior to freezing and not natural or artificial freezing. As most producers of artificial ice used tap water or spring water of drinking water quality, their ice was less contaminated than natural ice simply cut in any open body of available water. Therefore, it was generally correct, that artificial ice was less problematic with respect to cholera than domestic natural ice in Germany.
But how about imported ice from Norway? With pollution of the ice being nothing else than a direct consequence of pollution of the water prior to freezing, imported ice was by no means comparable to locally produced ice and in general terms completely unproblematic when it came to cholera. Did consumers realize the difference between imported and domestically produced ice? As the manufacturers of artificial ice focused on the difference between artificial ice and natural ice, the difference between imported and domestic ice became completely overshadowed and neglected. Imported ice from Norway became collateral damage due to the real existing issues with domestic natural ice.
The cholera issue accelerated the transition from natural to artificial ice in Germany (even if this transition needed several more decades to be completed) although the epidemic was not related to the question of ice being frozen by nature or by technology, but simply by the use of polluted or unpolluted water.
The Bacteriological Institute also tested artificially produced ice made from clear and clean drinking water. They sometimes found surprisingly high numbers of bacteria but classified them as harmless. The reason for these bacteria was often insufficient hygiene and cleaning of equipment…. Does it sound familiar again today??