Molecules, Microbes, and Meals: The Surprising Science of Food
by Alan Kelly
Oxford University Press, 2019
Reviewed by Purnendu C. Vasavada
Today’s consumer wants to know everything about food: what to eat for weight loss, energy, or a myriad of other health benefits. Consumers are also interested in safety and suitability as well as where foods come from and how they’re processed. The same is true for food industry professionals and artisanal food processors looking for basic information about food science and technology. Finding credible and scientifically sound information, however, isn’t easy. Opinions, commercially biased information, and myths and misconceptions about food and food processing abound. While there is substantial scientific literature on the various aspects of food chemistry, food microbiology, food processing, engineering, and technology, very little credible, non-nonsense, and understandable information is available for lay consumers.
In his recent book, Molecules, Microbes, and Meals: The Surprising Science of Food, Alan Kelly provides an overview of the science of food, exploring all aspects of how the foods we purchase and consume have come to have the characteristics they do. The author starts with a confession,“ I am a food scientist,” but presents the science of food in a unique style that’s clear, credible, and enjoyable. Using common foods such as yogurt and cheese, the book explains the basics about the chemical components of food and ingredients and their role in the characteristics, flavor, texture, and qualities of food.
The book discusses key aspects and complexities of carbohydrates, proteins, fats, and other constituents in an easy-to-understand manner. Kelly describes the chemical structure of casein and its role in cheese making in fascinating prose without the use of a complex diagram one would find in dairy chemistry textbooks. In explaining the many types and roles of microorganisms, the author invokes the famous Clint Eastwood western, “The Good, the Bad and the Ugly,” stating that (cue Ennio Morricone music and distinctive whistling) bacteria in food can be good (like probiotics), bad (like pathogens), or ugly (like the type that cause spoilage). He discusses spoilage bacteria, pathogens, spore-forming bacteria, and viruses in sufficient detail to explain what makes them grow and how we can control their growth or kill them to preserve and assure food safety. He also explains the Hurdle concept of food preservation in which salt, temperature, or preservatives are used to prevent the growth of microorganisms.
This books covers the principles of common food processing methods such as fermentation, concentration and dehydration, and freezing in a succinct yet effective way. Thermal processing such as pasteurization, including ultra-high-temperature and commercial canning, are explained thoroughly, including the principles of thermal lethality: – D-and Z- values. Kelly also covers novel food processing methods such as membrane filtration, high-pressure processing, and microwave heating. A separate chapter is devoted to discussing food packaging, including active, intelligent, and edible packaging.
One of the main focuses of the book is to explain the scientific underpinning of the flavor, texture, and qualities of food, and the transformations that occur when the products are cooked. The book also explores the convergence of science and art in food and the history of food. In this context the author describes the work of Nicholas Appert, who developed the art of appertization, a process of preserving food by placing it in a glass bottle, removing as much air as possible, and heating the sealed bottles in boiling water for a long period of time.
Finally, Kelly describes recipe development, formulations, and the sensory properties of foods, including appearance, flavor, texture, and taste. In this section he also includes information about the future of sensory science. He also covers the popular topic of molecular gastronomy, which, he explains, resulted from collaborations between chefs and scientists.