Updated: Jul 7
Canned food got its start in the beginning years of the 19th century in France and moved to America by 1825. It started to enter the average American homes in the years after the Civil War. The war exposed millions of soldiers to canned food and they brought the taste home with them.
Americans, however, were skeptical about this "new" way of eating food and the canned food industry struggled to convince American consumers to consider its products viable and trustworthy. There were many reasons why consumers were not that interested in trying these new offerings - the main one being that the food had to be boiled prior to canning, leaving its contents mushy with an unattractive texture and taste.
Another reason for being skeptical is that Americans were accustomed to seeing, touching and smelling the food they were about to eat and these hard-sided, metal objects did not fit the bill. The new method of industrial production and the new way of eating felt foreign to the consumers who grew up in a time when their meals were local, fresh and perishable. As the US entered into an era of industrialization and urbanization, the unfamiliar cans of food became embodied during that time of rapid change.
Innovations followed as the canning men - and they were mostly men - built their businesses from the ground up, hoping to overcome consumer resistance. The canners perfected machinery to build the cans and process the fruits and vegetables. They also organized professional trade groups and worked with agricultural scientists to grow crops that would fit well inside the can. These businessmen also invited the government to regulate the the canning industry by formulating food laws.
All of this did not exist without problems for the canners. One issue they commonly experienced was spoilage. Even though the canning process killed existing bacteria and created a vacuum seal to keep more bacteria from getting in, the methods they used weren't always foolproof. If the temperature of the water bath was too low, boiled unevenly, had low pressure for sealing, spoilage would occur.
Canners thus invested in bacteriology and public health oversight. With the acceptance of germ theory in the late 19th century, canners embraced this new awareness of the microbial life that could potentially wreak havoc on the industry. Beginning in the 1890s, the industry sponsored scientific work to address bacterial contamination. Before long, canners felt they had gained control over this microscopic foe.
Most canned food spoilage were fairly obvious - either the can itself became deformed (remember your elders telling you not to buy dented cans?) or its contents were visibly spoiled. Gastrointestinal issues and mild illness were present when the spoiled food was ingested.
But there was one rare kind of bacteria that was far from harmless: Clostridium botulinum. This bacteria produces botulinum, the deadliest toxin known to human kind, and which can not be detected by sight, smell or taste. Botulism doesn't itself cause cans to be externally deformed (dented nor bulging), but those external signs often suggest an insufficient canning process which can breed both botulism and other kinds of bacteria that have more visible effects. C. botulinum is also anaerobic, meaning it thrives in an oxygen-free environment, precisely that of canned food. Though it was rare, botulism terrified canners.
Their worst feats materialized in late 1919 and early 1920 when a series of deadly botulism cases struck unassuming consumers by killing 18 people in Ohio, Michigan and New York with smaller outbreaks elsewhere. The deaths were traced back to canned black olives, a mainstay of hors d'oeuvre plates and a delicacy often reserved for special occasions. The olives had been packed in California and then shipped across the country to various destinations, the result of a newly nationalized commercial food system.
The National Canners Association and California Canners League sprung into action, recognizing the particular vulnerability of botulinum infecting food. These botulism deaths - widely publicized in mainstream media outlets - threatened to undermine the still-shaky foundation of the canned food business, fueling the consumer's fear.
The canners worked on two fronts. Even as they sought to displace responsibility and downplay media coverage of the deaths, they helped initiate an expensive research and inspection campaign that set the groundwork for the American food safety system.
In early December 1919, the canning and olive industries came together to fund a Botulism Commission of scientific experts tasked with producing specific strategies for botulinum-free processed cans of olives to prevent such a crisis from happening again.
After much negotiation and research, the Botulism Commission's findings led to specific regulations for the processing of olives - 240 degrees Fahrenheit for at least 40 minutes - and a statewide inspection service, funded by the industries. This would be overseen by the California Board of Health. By 1925, many of these standardized practices had expanded to other food products, including sardines, tuna, and all vegetable products except tomatoes.
Throughout this laborious task, three distinct groups - scientists, canners and government officials - established a set of regulations. As they got to know each other and worked through any differences, they built the network that would be the basis of the nation's food system. Because the canning industry had taken a lead role in this network, many fears that the Americans had slowly dissipated. Acceptance of the canned food was finally present.
Presently, we are all part of an accepted food system that contains numerous processed foods. We now trust that dented cans (or any cans) are very unlikely to harbor botulinum and we eat and unthinkingly trust processed food. The country still experiences occasional food safety outbreaks, but rarely from canned food.
This all leads to the purpose of writing this. As a food manufacturer of an all-botanical tea, I am under strict regulations that were established by the canning industry. This is because C. botulinum is prevalent in soil and marine sediments worldwide, most commonly as spores. These spores are found everywhere and on many things, including plants. While the spores are generally harmless, the danger can occur once the spores begin to grow out into active bacteria and produce neurotoxins. As discussed before, this bacteria infestation can live in an environment without oxygen and when we process the tea, and seal the cap, we have an oxygen-free environment.
Currently, the steadfast and reliable regulation regarding the prevention of botulinum infection is to monitor the pH of this herbal tea. The organism grows best under low-oxygen conditions and produces spores and toxins. The toxin is most commonly formed when food is improperly processed (canned) at home. C. botulinum cannot grow below a pH of 4.6, so acidic foods, such as most fruits, tomatoes, and pickles, can be safely processed in a water bath canner or container. Through much trial and error and research, I have found that the sheep sorrel is the key ingredient of my tea in regards to keeping the pH below 4.6. I have had to add more sheep sorrel to this recipe in order to be able to safely keep it in an acidic environment. Without it or at low quantities, the tea could contain these spores.
Because I deal with only 2 separate vendors, I am assured every single bottle I produce is consistently the same. I have to monitor the pH after every single batch and after 27 years of cooking this tea, I am completely satisfied that my tea is 100% safe. In addition to monitoring the pH, we bring the tea to a boil to assure the destruction of any other bacteria and we bottle at no less than 180 degrees (another regulation that was established by the canning industry).
You can be assured you are getting a safe, drinkable tea and I would advise anyone who is taking another's premade essiac to question what regulations they fall under in regards to temperature control and pH monitoring.
Be safe, be well, be good.
Chris Corpening, RN, owner, A Nurse's Tea LLC
Canned: The Rise and Fall of Consumer Confidence in the American Food Industry by Anna Zeide