Since for centuries it had been understood that warm weather turned milk, farms were equipped with “spring houses,” rooms that were cooled by the constant flow of cold water from wells or springs. Since it was also believed that milk would spoil in a thunderstorm—perhaps because of the lightning—it was often kept in containers made of a nonconductive material such as glass.
Consumers had long been provided with household tips on how to judge milk. Here is Elena Molokhovets’s advice:
Good milk is somewhat heavier than water, because drops of milk sink in water. If whole, good milk, is dropped on a fingernail, the round drops will hold their shape, but milk diluted with water will spread out. Good milk is thick and pure white, but adulterated milk is thin and falls in a bluish tint.
Rub some between your fingers to determine whether or not it is fatty.
1926 French 90-centime Louis Pasteur stamp.
She also pointed out that boiling milk, the leading way of purifying it from possible diseases, robbed milk of its nutrients.
The existence of bacteria had been known since the late seventeenth century, when the Dutchman Anton van Leeuwenhoek built a microscope that magnified subjects 270 times, as opposed to previous devices that at best magnified 50 times. With this tool he could see many little creatures, bacteria, squirming in a drop of water. But until Pasteur, there was no solid understanding of what bacteria did. Even the word “bacteria” did not exist until the German naturalist Christian Gottfried Ehrenberg came up with it in 1838. Scientists were also only beginning to understand that bacteria existed not only in water, but everywhere.
Pasteur’s theory held that some of these bacteria, called “germs,” caused disease, but he couldn’t prove it. At the time, it was widely believed that diseases were caused by miasmas, vapors that rose from the earth. In 1854, John Snow, an English physician who championed hygiene in medicine as well as the use of anesthesia, claimed that cholera was spread through germs that lived in unclean water. But few believed him.
William Budd, an English country doctor, the son of a doctor, and one of seven out of ten siblings who were doctors, from 1857 to 1860 published a series of articles in the Lancet showing that typhoid was not spread by bad air but by contagion, from person to person. Though many rejected his findings, he continued to study typhoid epidemics and found much evidence that supported his conclusions. A teacher in the Bristol Medical School, he also advocated for the use of disinfectants, or germ killers, and by the time he published Typhoid Fever in 1874, he had significantly altered the medical approach to epidemics. A 1849 cholera epidemic in Bristol had killed two thousand people. In 1866 another cholera epidemic hit the city, and this time, thanks to the implementation of Budd’s ideas, only twenty-nine people died.
Robert Koch, a German Nobel Prize–winning scientist who taught himself to read at the age of five by studying newspapers, brought more new ideas to medicine and milk. In 1860 he studied anatomy at the University of Göttingen under Jacob Henle, a disciple of the new “germ theory.” Koch then examined the spread of anthrax, an infection caused by a spore-forming bacterium, while he was serving in the German Army in the Franco-Prussian War. With no equipment, he used wooden splinters to inject the anthrax-causing bacteria into mice (ouch!). He went on to work on the spread of other diseases, and in 1882 he concluded that there were three distinct tuberculosis germs: a rare one spread by birds, a common one spread from one person to another, and a third one, not as rare as the first nor as common as the second, spread through milk.
This 1882 discovery, really proof of a belief that had existed for some time, changed the dairy industry. It led to what really should have become known as the “kochization of milk,” not the “pasteurization of milk,” as we call it today. But Pasteur was the one who identified the process to eliminate the disease that Koch had later discovered.
Bovine tuberculosis, a disease found in cattle, is transmitted to humans through milk. It attacks the glands, intestines, and bones. Humans who survive the disease often become hunchbacked or deformed in other ways. Children are particularly susceptible and are often kept in braces for years to keep their spines from becoming deformed.
Research by the British army in Malta in the 1880s and 1890s led to the discovery of another germ that could be transmitted to humans through cow, sheep, or goat’s milk. It caused what was called Mediterranean fever, whose symptoms were severe joint pain, sweats and chills, and fevers that lasted as long as six months. On occasion, the symptoms were permanent. The bacterium that caused the disease was named Brucellosis, after the British doctor David Bruce, though historians believe that the discovery of the disease should be credited to the Maltese doctor under him, Themistocles Zammit.
A similar discovery, bad news for goat’s-milk advocates, was that raw goat’s milk can carry a bacterium called Brucella melitensis, which causes undulant fever, heavy perspiration, and aching joints, a condition that can last for weeks or months.
The more scientists investigated, the more milk-borne diseases they found. Serious intestinal diseases could be transmitted through milk from unclean udders. Farmworkers with contagious diseases could transmit them through the milk pail. Scarlet fever, diphtheria, and typhoid were all traced to contaminated milk.
Milk then became the first laboratory-tested food. In 1887 the U.S. Public Health Service, a government agency founded in 1870, established a laboratory for that purpose.
In 1892 the United States started testing all dairy herds for bovine tuberculosis. The test had been developed accidentally by Robert Koch while he was trying to develop a vaccine against the disease. His vaccine hadn’t worked, but the cows that were injected with it developed an inflammation at the injection point if they had the disease. It became a way of testing for the tuberculosis bacillum, and the results were horrifying. A significant portion of American cows, and by extension American milk, was infected. The infected cows were then removed from the herds, and the number of cases of bovine tuberculosis in humans dramatically declined.
In the 1880s the idea of sterilized milk came to the United States. It was believed that the lives of babies could be saved if they were fed milk that had been boiled and then cooled. Louis Pasteur had developed the sterilization process in France in the 1850s and 1860s. As a passionate believer in science serving industry, he had taken a professorship in Lille in northern France, a region of distilleries, in 1854. He had wanted to learn why liquids soured and spoiled, and so resolved to examine all substances that fermented to see if they all contained living organisms. He started with milk because he thought it would be the simplest to demonstrate. It was more difficult than he had imagined, but he did manage to show that lactic acid fermentation was caused by living organisms.
Still only thirty-five years old, Pasteur then left milk to study other substances and the larger questions of where these organisms came from and how to get rid of them. He discovered that wine that had gone sour contained active living organisms, but if heated to between 140 and 158 degrees Fahrenheit (far cooler than the 212 degrees at which water boils) and kept at that temperature for a few minutes and then rapidly cooled, the wine never soured. This was the original pasteurization process. Pasteur went on from there to work on many other projects, including research in the field of immunization against diseases such as anthrax, cholera, and rabies.
By the time the word “pasteurize” was applied to milk, Pasteur was in the final years of his life; he died in 1895 at the age of seventy-two. He had developed the pasteurization process in 1864, but it took decades before scientists began to apply it to milk. When they did, they found that if they heated milk for twenty minutes to just below its boiling point and then rapidly cooled it, it would neither sour nor carry diseases. The process also killed the good bacteria, however, which is why many cheesemakers refuse to use pasteurized milk. Some consumers then and now complain that pasteurized milk is dead. But it was also argued that boiling destroyed everything, but pasteurization, because
it was below the boiling point, allowed nutritive elements to live.
With the new science there were two possible approaches to milk as a public health problem. Government could require the pasteurization of all milk, despite the fact that many people disliked it, or they could set up a system of inspection to guarantee the quality of raw milk, which was called “certified milk.” Henry Coit, a Newark, New Jersey, physician, established a network of panels of physicians, known as a medical milk commission. The first bottle of certified milk was produced by the Fairfield Dairy in 1894. In 1907, commissions from around the country had banded together to found the American Association of Medical Milk Commissions. A certificate from a commission earned the right to label the milk as certified milk, which would fetch a far higher price. But as would happen with other special-quality milks in the next century, the consumer was not willing to pay a high enough price to cover the added cost of certification.
Meanwhile, in cities such as New York, Boston, Philadelphia, and Chicago, infant mortality remained high for the next twenty years while the merits of pasteurization and certified milk were debated.
Nathan Straus, born in Germany in 1848, emigrated to a small town in Georgia in 1856 with his two brothers and mother to join his father, who had moved there two years earlier. But the Straus family lost most of their money during the Civil War, and in 1865 they moved to New York, where the Straus brothers eventually gained control of two of New York’s largest department stores, Macy’s and Abraham and Straus.
Nathan Straus was guided by a social conscience. He provided low-cost lunches and health care to his employees. In the harsh winter of 1892–93 he distributed coal to the poor and provided affordable lodging for the homeless. He was concerned about the high infant mortality rate in New York City and became convinced that it was caused by milk and that the solution was pasteurization. In June 1893 he opened the first of what he called “milk depots” on the East Third Street pier in the impoverished immigrant area of the Lower East Side. In fact, the first depot had been opened in the same neighborhood four years earlier by a New York pediatrician, Henry Koplik. Pure pasteurized milk was sold at Straus’s depot for four cents a quart, and free milk was available for those who could not afford even this extremely low price.
Milk from cows inspected by veterinarians of the New York Board of Health was now being shipped to the city in ice-cold railroad cars. Straus had his own plant, where milk was kept on ice until it was pasteurized and bottled. Crowds came to the depot every day to buy fresh milk and sit in a tent by the river where doctors were on hand to dispense medical advice and examine children.
Nathan Straus’s milk station in City Hall Park, Manhattan. (Museum of the City of New York/Art Resource, NY)
Next, Straus opened five more depots in other New York neighborhoods; in their first year, they dispensed 300,000 bottles of pasteurized milk. Soon he had twelve depots in New York City, all of which operated at a financial loss. In fact, the depots cost him more money than his share of the department stores’ earnings. But he was on a mission. And he believed that milk was the perfect food, the perfect balance of protein, carbohydrates, and fat.
Since it was widely believed at the time that pasteurized milk had an odd taste, Straus also set up stands in the parks where the public could sample it for a penny a glass. He decided to launch a national campaign and wrote letters to the mayors of the largest cities offering to establish milk depots.
In his crusade for pasteurization, Straus often referred to an incident that had occurred on Randall’s Island in the East River between Manhattan and Queens. The island was being used as an orphanage, and in order to ensure that the children had a ready supply of good, clean, fresh milk, a dairy herd was maintained there. But between 1895 and 1897, while the 3,900 children were being fed supposedly safe raw milk, 1,509 of them died.
In response to this frightening statistic, Straus built a pasteurization plant on the island. He made no attempt to change the children’s diet or improve the orphanage’s hygiene, just pasteurized the milk. The mortality rate declined from 42 percent of the children to 28 percent. A 28 percent child mortality rate would still horrify most people today, but in 1898 it was considered a remarkable improvement.
Milk depots were established in Boston, Chicago, Philadelphia, Cleveland, Chicago, and St. Louis. But many people in both Europe and America, and even in France, where Pasteur was revered, did not like pasteurized milk. The public complained about its taste. British farmers complained that the pasteurization machines were too expensive. Some doctors argued that milk lost its nutritional value when it was pasteurized.
In the United States, people also fought about a proposal to make pasteurization mandatory and raw milk illegal. In the spring of 1907, advocates of pasteurization, led by Straus, proposed an ordinance banning the sale of raw milk in New York City. At a rally for the ordinance, Straus said, “The reckless use of raw, unpasteurized milk is little short of a national crime …”
Dairy farmers who did not want to pay for pasteurization opposed the ordinance, as did those who thought that pasteurization would give farmers a false sense of security and lead to a decline in farm hygiene. Some even argued that it was better to eat live bacteria then dead ones—pasteurized milk being nothing more than milk with dead organisms floating in it.
The alternative was still certified milk, developed at Harvard Medical School in 1891. Rather than give in to cooked, dead, pasteurized milk, raw milk could be produced with greater care. Everything could be closely monitored—from the health of the herd to the hygiene of the farm to all the stages that milk passed through until sold in the market. But certified milk was expensive to produce and usually available only through doctors.
Advocates of pasteurization often acknowledged that raw milk had more nutrients than pasteurized milk, but they still insisted that pasteurized milk was safer to drink. Advocates of certified milk, or “clean raw milk,” said that it, too, was safe, and continued to lobby for their cause. Among their supporters was the New York City Health Department, who was adamant that the solution lay in more rigorous inspection. Straus’s proposed ordinance was defeated in May 1907.
What was being called the Milk Question attracted the interest of President Theodore Roosevelt, a native New Yorker with a reputation as a reformer. He ordered the Public Health Service to study the issue. They commissioned a panel of twenty supposed experts on dairy and in 1908 published a report concluding that raw milk was dangerous and that pasteurization did not alter the composition or flavor of milk. Many disagreed with the panel’s findings, as is still the case today.
The pasteurization cause was not helped by the fact that other studies of boiled and evaporated milk showed that cases of rickets, a debilitating bone disease, could be traced to the “new milks.” A number of cases of scurvy were traced to a lack of vitamin C in the milk.
In August 1908, Chicago became the first city to mandate the pasteurization of milk. After January 1909, all milk sold in Chicago had to be pasteurized. The only exception was raw milk from cows that had tested tuberculosis-free for a year. This was very close to saying that certified milk was also approved. The state’s dairy farmers fiercely opposed the ordinance and went to court, claiming that it was a violation of free trade.
In New York in 1909, Straus tried again to have his proposed ordinance passed and was again turned down. But a year later, the city’s health department changed its position and ruled that all milk for drinking had to be either boiled or pasteurized. In 1911 the National Commission on Milk Standards accepted both certified and pasteurized milk and declared that all milk should be one or the other. The American Medical Association came to a similar conclusion.
Union Settlement House, New York City, free milk program. Photo by Roy Perry. (Museum of the City of New York/Art Resources, NY)
Meanwhile, Straus continued to argue that his ordinance would save babies’ lives. He said, “Its defeat means babies killed.” The ordinance cam
e up for a vote again, and this time an overwhelming majority voted for it. In 1912 it became illegal to sell unpasteurized milk in New York. By 1914, 95 percent of New York City milk was pasteurized. By 1917, 46 major U.S. cities were requiring milk to be pasteurized.
At first, the method of choice for pasteurization was what was called “the flash method.” Milk was heated to 184 degrees Fahrenheit for only a few seconds. But then it was found that more bacteria were killed by “the holding method,” the one used at Straus’s milk depots. It involved heating the milk to a lower temperature and holding it there for twenty minutes. This method became the established approach as the entire country moved to pasteurized milk.
Pasteurization was a public health decision, not a medical one. It is perfectly possible to ensure the safety of raw milk, as is sometimes done in other countries. But pasteurization is far easier to enforce; guaranteeing raw milk is a complicated and expensive process. This is of no comfort to people who prefer raw milk either for its taste or because they believe that it is more healthful.
Once Americans became confident that the milk they loved was safe, it took on what was at times an almost bizarre importance. In 1923 the future President Herbert Hoover, then Secretary of Commerce, addressed the World Dairy Congress with the words:
Upon this industry, more than any other of the food industries, depends not alone the problem of public health, but there depend upon it the very growth and virility of the white race.
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