Research into fermentation is stimulating and leavens the mind. But it is difficult to find clear answers to questions that involve microbiology yet require a high level of integration of many different fields of study. This despite the fact that fermented foods are part and parcel of almost all daily meals.
Fermentation is often a multivariate operation, where the activity of many species of bacteria, yeasts, and mold must be carefully orchestrated in time sequence, along with a continually evolving reactive ecosystem of any of water, sugar, salt, carbon dioxide, alcohol, and acetic acid so as to produce an optimal, flavorful, nutritious product.
Best practices and traditional recipes have been developed over millenia via trial-and-error, with absolutely no understanding of the biological factors involved until the mere century and a half since Pasteur provided clear indications that fermentation was the result of microbial activity.
Salt and lactic and acetic acids produced by fermentative bacteria work in tandem to preserve vegetables such as pickles by making the environment inhospitable to the many bacteria responsible for spoilage. Salt and brine solutions actually dehydrate the vegetables through osmosis, which prevents the easy growth of microbes.
Lactic and acetic acids produced by fermentative bacteria in most fermented foods reduce the pH of fermenting media, which kills off most microbes besides those acid tolerant strains responsible for fermentation, which happen to be able to withstand such environs. Yeast, if present, produce carbon dioxide, which reduces the oxygen level of the medium, thereby selecting for the anaerobic bacteria that aid in fermentation, as well as triggering the anaerobic cycle of yeast respiration that leads to alcohol production, which also kills off more harmful microbes. Molds, being aerobic in nature, generally sit on the surface and can be scooped off or left to grow on certain foods like camembert and rocquefort, often producing more antimicrobial products.
We Americans love the combined taste of salt and vinegar, especially on potato chips. What is the relationship between this taste preference and the preservative powers of these two ingredients?
Given our preference for having a variety of foodstuffs available in stores across the globe, foods must be preserved to withstand the transportation from locales where they can grow to locales where they can be afforded. This has led to commercial genetic modification to produce hardier, more disease-resistant produce that reproduce quickly, grow larger, select for traits such as sweetness that are traditionally associated by the consumer with “ripeness”, and won’t bruise when bumping along pot-holed highways in third-world countries.
Critics of such commercial pressures on the food industry claim that such food is less flavorful and less nutritious, as well as being harmful to indigenous ecosystems through the introduction of genetically modified superplants and animals. If we are to maintain the availability of the variety of foods, yet revert to a more “natural” food industrial process, we will need alternative methods of food preservation during transportation and shelf life. Does fermentation play a part in this?
Couldn’t we develop an energy-intensive unfermentation process to revert fermented foods to something close to their original composition?
Pasteurization and sterilization of foodstuffs obviously allows for easier transportation, lower risk of contamination, and longer shelf life. Yet, what adverse affects does this limited exposure to microbes have upon our health and immunity, which we know depend a great deal upon microbial exposure and bi-products. And how have we compensated for the lack of fermented flavor through the use of artificial flavor enhancers? How has local culture and tradition suffered as a result of standardization and sterility of food and drink? What would be the utility of sterility and durability if foods were locally produced? How has supermarket culture inhibited certain populations’ ability to access quality food, and how can greater reliance upon living organisms in fermented and preserved foodstuffs address that? And how would greater ingestion of non-sterile fermented foods affect nutrition, immunity, and health?
More fodder for research.