A Brief History of Milk Hygiene and Its Impact on Infant Mortality from 1875 to 1925 and Implications for Today: A Review.

The objective of this review is to provide an integrated historical account of the complex, often convoluted events impacting milk hygiene and its resultant effect on infant mortality from 1875 to 1925. Heat pasteurization of cow's milk is necessary for rendering this important nutrient source safe for humans-particularly infants. Developed by Louis Pasteur in 1864, pasteurization evolved from the commercially important parboiling of wine and beer when the Industrial Revolution was effecting rapid societal change in Western societies. In European and American societies of the early and mid-19th century, infant mortality rates were 30- to 60-fold higher than the current rates of five or six deaths per 1,000 live births per year. With proof of the germ theory of disease came convincing evidence of the role of microbes in the transmission of infections, which led to the discovery that microbial pathogens were transmissible via milk. Diseases caused by milkborne pathogens include human and bovine tuberculosis, brucellosis, salmonellosis, streptococcal infections, diphtheria, and "summer diarrhea." With pasteurization of milk, infectious diseases with their high infant mortality rates decreased by only half by the early 20th century, despite concurrent medical and dairy hygiene advances. To further mitigate unacceptably high infant mortality rates, social support providers-including public health nurses and midwives-encouraged breastfeeding, especially among socioeconomically disadvantaged mothers. Improvements in pulsating vacuum milking machines also favorably impacted food safety by providing a clean, enclosed environment. Currently, bottle feeding still competes with breastfeeding as the preferred method, and the sale of raw, unpasteurized milk remains a contentious issue. Informed and responsible food safety professionals, physicians, and public health officials currently view breastfeeding as the preferred feeding method and milk pasteurization as the safer and more prudent alternative.

A 100-Year Review: A century of dairy processing advancements-Pasteurization, cleaning and sanitation, and sanitary equipment design.

Over the past century, advancements within the mainstream dairy foods processing industry have acted in complement with other dairy-affiliated industries to produce a human food that has few rivals with regard to safety, nutrition, and sustainability. These advancements, such as milk pasteurization, may appear commonplace in the context of a modern dairy processing plant, but some consideration of how these advancements came into being serve as a basis for considering what advancements will come to bear on the next century of processing advancements. In the year 1917, depending on where one resided, most milk was presented to the consumer through privately owned dairy animals, small local or regional dairy farms, or small urban commercial dairies with minimal, or at best nascent, processing capabilities. In 1917, much of the retail milk in the United States was packaged and sold in returnable quart-sized clear glass bottles fitted with caps of various design and composition. Some reports suggest that the cost of that quart of milk was approximately 9 cents-an estimated $2.00 in 2017 US dollars. Comparing that 1917 quart of milk to a quart of milk in 2017 suggests several differences in microbiological, compositional, and nutritional value as well as flavor characteristics. Although a more comprehensive timeline of significant processing advancements is noted in the AppendixTable A1 to this paper, we have selected 3 advancements to highlight; namely, the development of milk pasteurization, cleaning and sanitizing technologies, and sanitary specifications for processing equipment. Finally, we provide some insights into the future of milk processing and suggest areas where technological advancements may need continued or strengthened attention and development as a means of securing milk as a food of high safety and value for the next century to come.

A 100-Year Review: Cheese production and quality.

In the beginning, cheese making in the United States was all art, but embracing science and technology was necessary to make progress in producing a higher quality cheese. Traditional cheese making could not keep up with the demand for cheese, and the development of the factory system was necessary. Cheese quality suffered because of poor-quality milk, but 3 major innovations changed that: refrigeration, commercial starters, and the use of pasteurized milk for cheese making. Although by all accounts cold storage improved cheese quality, it was the improvement of milk quality, pasteurization of milk, and the use of reliable cultures for fermentation that had the biggest effect. Together with use of purified commercial cultures, pasteurization enabled cheese production to be conducted on a fixed time schedule. Fundamental research on the genetics of starter bacteria greatly increased the reliability of fermentation, which in turn made automation feasible. Demand for functionality, machinability, application in baking, and more emphasis on nutritional aspects (low fat and low sodium) of cheese took us back to the fundamental principles of cheese making and resulted in renewed vigor for scientific investigations into the chemical, microbiological, and enzymatic changes that occur during cheese making and ripening. As milk production increased, cheese factories needed to become more efficient. Membrane concentration and separation of milk offered a solution and greatly enhanced plant capacity. Full implementation of membrane processing and use of its full potential have yet to be achieved. Implementation of new technologies, the science of cheese making, and the development of further advances will require highly trained personnel at both the academic and industrial levels. This will be a great challenge to address and overcome.

From swill milk to certified milk: progress in cow's milk quality in the 19th century.

BACKGROUND: Industrialization and urbanization jeopardized infant nutrition during the 19th century. Cow's milk was produced in the cities or transported long distances under suspect conditions. Milk was contaminated with bacteria or adulterated with water, flour, chalk and other substances. When distilleries proliferated in the metropoles, their waste slop was fed to cows which then produced thin and contaminated swill milk. SUMMARY: Following a press campaign in the USA, the sale of swill milk was prohibited by law in 1861. Bacterial counts became available in 1881 and helped to improve the quality of milk. Debates on pasteurization remained controversial; legislation varied from country to country. Disposal of the wastewater of millions of inhabitants and the manure of thousands of cows was environmentally hazardous. It was not until 1860 and after several pandemics of Asiatic cholera that effective sewage systems were built in the metropoles. Milk depots were established in the USA by Koplik for sterilized and by Coit for certified milk. In France, Budin and Dufour created consultation services named goutte de lait, which distributed sterilized milk and educated mothers in infant care. MESSAGE: Multiple efforts to improve milk quality culminated in the International gouttes de lait Congresses for the Study and Prevention of Infantile Mortality.

Technical inventions that enabled artificial infant feeding.

Artificial feeding of infants, called hand-feeding, was unsafe well into the 19th century. This paper aims to identify technical innovations which made artificial feeding less dangerous. In rapid succession from 1844 to 1886, the vulcanization of rubber, production of rubber teats, cooling machines for large-scale ice production, techniques for milk pasteurization, evaporation and condensation, and packing in closed tins were invented or initiated. Remarkably, most of these inventions preceded the discovery of pathogenic bacteria. The producers of proprietary infant formula made immediate use of these innovations, whereas in the private household artificial feeding remained highly dangerous - mostly because of ignorance about bacteria and hygiene, and partly because the equipment for safe storage, transport, preparation and application of baby food was lacking.

Infectious milk: issues of pathogenic certainty within ideational regimes and their biopolitical implications.

Throughout the 19(th) century and early decades of the 20(th) century, milk was a dangerous food that required state intervention to make it safe. Throughout this period, the germ theory of contagious disease came to prominence, but could not explicitly determine the causal relationships linking germs, milk, and human illness. Using the notion of an ideational regime, I examine how (1) knowledge claims move from uncertainty to certainty and become privileged claims within ideational regimes that (2) result in an unintended, but necessary deployment of a biopolitical strategy for governance. The argument here is that theoretical uncertainty meant managing populations as a uniform undifferentiated reality using pasteurization technologies. I use two historical moments as evidence of these processes. The first is the 1901 British Congress on Tuberculosis when I argue germ theory came to a theoretical standstill and the second is Ontario's 1938 amendment to the province's Public Health Act that permanently institutionalised province-wide compulsory pasteurisation laws organised around the notion of nutritional equivalency. This genealogical exploration should provide some insight into how bacteria became the singular cause of illness and into the conditions that led to targeting milk as the main site of intervention instead of treating individual bodies.

The pasteurized state: milk, health and the government of risk.

In the late 1940s, Florence Sabin, a retired professor of medicine, returned to her home in Colorado to launch a massive public health campaign. Seeing "filthy milk" as an important vector of disease, she struggled not just pasteurized milk, but a pasteurized state government that was capable of regulating the milk industry. In the process, she brought managerialism into public health by fighting against the political machines and introducing Robert McNamara's systems analysis into government for the first time. Sabin's innovation, which united business, government and public health in new ways, transformed the way that public health is managed even today.