Morgan Venable

The Complex Relationships Between Humans, Food, Water, and Hygiene

Humans have very complex and intricate relationships with food water not only because they are after Oxygen, the most essential elements for life and metabolic requirements for the life of all animals, but also because along with the concept of hygiene they are object of heated discussion and controversies. In general food safety ranks as one of the highest priorities in most developed countries, but in the rest of the less privileged world more fundamental needs of achieving international water sanitation targets and food security are more imperative. The global life expectancy at birth has increased in recent years but child obesity as well. The current public opinion about food and water related risks vary greatly, and differences between perceived risks and real risks seem to be centered on natural ethnocentrisms, which not only guides the choice of foods but also our perception and management of food related risks.

Biocides and “Superbugs”

Antibiotic resistance is one billion years old and “only holds clinical importance if it is related to the outcome of treatment associated with a pathogen.” Human applications lead to the transfers of resistance genes to pathogenic and agriculture microorganisms and contribute “to the maintenance and/or amplification of resistance gene reservoirs.” Antibiotic resistance is sometimes linked and selected by some sanitizing agents as well. Sanitizing agents are not applicable against mixed biofilms in all contexts, especially on edible food surfaces where they might not be effective or allowed by local regulations.

Food Microbiology Seen from Different Angles

With the gradual acceptance of the germ theory of disease, excessive emphasis was given to the pathogen, which was considered to be the only cause of disease. The triad concept of disease was developed in plant pathology to account for the roles of the environment and the susceptible host in disease development as well. Since animals unlike plants have more complex defense mechanisms and can escape from diseases, we must consider host-pathogen interactions, environmental conditions, and intrinsic and extrinsic factors of the host, such as the immune systems and the microbiomes, as well as the ability of the host to escape and avoid contagion by taking appropriate decisions based on food risks. An octahedron model can therefore help in the visualization of these complex interactions, as they will be discussed in the following chapters in such order.

The Human Microbiomes

The human microbiomes can be seen as “the entire collection of genes found in all of the microbes associated with a particular host” and the entire “collection of microbes that live in the human habitat”. These microbial associations have specific locations and functions. Skin diseases are frequently associated with a destabilization of skin microbes. In oral health, the current and frequent approach “to maintain oral health relies on the concept of stabilizing oral microbiota” in a compatible state with health. Intestines and colon contain the “densest known microbial communities on Earth”, and changes in its composition have associated to disease such as “irritable bowel syndrome, inflammatory bowel disease, allergic diseases” and “autoimmune disorders, diabetes, obesity and gastrointestinal cancer”.

The Fungi and Other Eukaryotic Microbes

Originally placed among the plants, fungi are in reality more closely related to animals. They are the only microorganisms with chitin on their cell wall. As saprophytes they are essential in degrading organic matter”, they interact with almost all vascular plants, and can be “trans-kingdom pathogens” as well. They also produce enzymes and secondary metabolites, which are essential to the pharmaceutical and to the food industry. Besides antibiotics, common foods require the assistance of fungi. In cheeses fungi “produce flavors and cause desirable changes in texture and appearance of the finished products”. Molds are “critical in the production of safe and high quality products such as salami and hams”. Although some molds produce dangerous toxins, the vast majority of fungi are considered beneficial and indispensable to the agricultural- food- continuum.

Food Safety Considerations About Selected Causative Agents

Microbial pathogens are not different from other life forms, and ultimately “we are all hosts and prey, parasites and predators.” Even common terms like pathogens and infections are defined differently according to the scientific discipline concerned. Foodborne diseases depend on the integration of complex set of circumstances, and “almost any bacterial species is capable of producing intestinal symptoms if swallowed in sufficient numbers.” “Outbreaks occur whenever pathogenic agents in sufficient number or quantity encounter a susceptible population without effective interceptive measure,” and “if we did not expect it,” we would assume that it “emerged.” The ultimate sources of foodborne pathogens directly or indirectly are humans and animals, and as our knowledge progresses, we have to face the fact that “microorganisms are opponents with whom we cannot race on their terms.”

Conclusions and Recommendations for Those Outside or Inside the “Global Village”

In the last century humans have contracted into a “global village,” and although more people have gained access to improved drinking water, and even if children mortality caused diarrheal diseases has steadily decreased in the last two decades, food safety remains “a privilege of the wealthy” because in many parts of the world achieving an adequate food supply takes the precedence over food safety. Pathogens can travel around the globe faster than ever before, and the focus on food safety has changed over time. Human environmental pressure on the planet’s ecosystems has escalated to an unprecedented level, but our ability to predict the responses of microbes to ongoing changes are still very limited. International regulations and recommendation for the food trade have been established, but their interpretation and application still differ markedly among and within countries. Consumers are the ultimate decision makers on their food safety, and sound food safety education should start early in everyone’s lives.

A Brief History of Food, Food Safety, and Hygiene

Humans must have developed some rudimentary concept of food conservation very early on during the gathering and hunting era in order to survive. It is not possible to establish with precision when fire started to become more than a source of warmth and protection. Awareness of the presence and role of microorganisms in foods is usually believed to have started in the Neolithic with the advent of agriculture. Over time all civilizations became aware of the importance of hygiene and the danger of pests in the etiology of contagious diseases. Some techniques of food preservation, fermentation and vaccination began long before the germ theory of diseases was accepted. Other preventive measures such as food prohibitions and quarantine were taken before the onset of microbiology. Hand disinfection was met with skepticism from the medical community before its importance was finally recognized. Modern microbiology is now able to go “beyond the Koch’s postulates” to understand some previously “false negative” conclusions.

The Human Behavior and Food Resources

Humans have travelled extensively in search of new food sources from ancient times and found new resources and exotic plant species around the world to use as food. But they had to face plant pathogens, which changed their plans and habits entirely. Microbial competition by plant pathogens and invasive species has profound effects on human populations. Currently for the first time, urban population is more than rural population. Global fertility is rapidly declining, while life expectancy is rising and as a consequence, individuals aged 60 years or older are outnumbering children under 5. Such changes are not only limited to urban sprawl but they force changes in the logistics of commodities and old-age support ratios. In turn people in situations of limited social security systems face greater risks of poverty and consequent greater water and foodborne risks.

The Local Food Environments

Food conservation is one of the first examples of microbial environments manipulated by humans. Humans have applied “hurdles” to spoiling and pathogenic microbes such as salting-drying, acidification, fermentation, osmotic pressure, oxygen exclusion, heating, chilling, natural preservatives, alone and more recurrently in combinations for centuries. Traditional empirical methods represent an enormous wealth of cultural diversity in food preservation. Hurdle technology combines tradition and science with multiple hurdles, which act synergistically against spoilage and pathogenic organisms in traditional as well as in most modern foods produced and preserved around the world.