FOOD SAFETY
Food is a source of nutrients not only to humans but to microorganisms as well. The organic compounds and moisture that are often present in foods present an ideal environment for the growth of various microorganisms. The monitoring of the raw food and of any processing steps required prior to the consumption of the food are necessary to prevent transmission of disease-causing microorganisms from the food to humans.
Bacteria, viruses, parasites, and toxin by-products of microorganisms, chemicals, and heavy metals can cause food-borne maladies. These agents are responsible for over 200 different foodborne diseases. In the United States alone, foodborne diseases cause an estimated 75 million illnesses every year, and 7,000 to 9,000 deaths.
Aside from the human toll, the economic consequences of foodborne illnesses are considerable. In 1988, for example, human foodborne diarrheal disease in the United States cost the U.S. economy an estimated five to seven billion dollars in medical care and lost productivity.
The threat from foodborne disease causing agents is not equal. For example, the Norwalk-like viruses cause approximately 9 million illnesses each year, but the fatality rate is only 0.001%. Vibrio vulnificus causes fewer than 50 cases each year but almost 40% of those people die. Finally, the bacteria Salmonella, Listeria monocytogenes, and Toxoplasma gondii cause only about 20% of the total cases but are responsible for almost 80% of the total deaths from foodborne illnesses.
The Centers for Disease Control data has demonstrated that Campylobacter jejuni is the leading cause of foodborne illness in the United States. Another bacteria, Salmonella is the next leading cause. The third cause of foodborne illness is the bacterium Escherichia coli O157:H7. Poultry and ground meat are prime targets for bacterial contamination. Indeed, monitoring studies have demonstrated that some 70–90% of poultry carry Campylobacter jejuni.
Food safety needs to consider the influences of the microbial pathogen, the human host and the exposure of the food to the environment that promotes contamination. The environment can include the physical parameters such as the temperature, moisture, or other such factors. As well the environment can be the site of the foodstuff, such as the farmyard or the processing plant. Ensuring safety of food from microbial threat must consider all three of the influences. For example, reducing the length of time that a food is exposed to a questionable environment, but doing nothing to remove microbes from the environment only slightly reduces the risk of food contamination. Significant protection of foods depends on reducing the risk from the environment, microorganism of interest and of the human host.
The treatment of foods prior to consumption is a vital factor in ensuring food safety. Some of these treatments have been known for a long time. Salting of meats and drying of foods on long sea voyages was practiced several centuries ago, for example. The canning of foods began in the eighteenth century. Within the last 150 years, the link between hygienic conditions and the quality and safety of foods was recognized. Some of the advances in food safety arose from the need for foods on long military campaigns, such as those undertaken by Napoleon in the nineteenth century. Also, advances were spurred by the demands of the nascent food industry. As the distance between the farm and the market began to grow larger, and the shipping of food became more commonplace, the problems of food contamination became evident. Practices to render food safe for shipping, storage and subsequent consumption were necessary if the food industry was to grow and flourish.
The heat treatment of milk known as pasteurization began in the 1890s. Pasteurization is the transient exposure of milk to temperatures high enough to kill microbes, while preserving the taste and visual quality of the milk. Milk is now routinely pasteurized before sale to kill any bacteria that would otherwise growth in the wonderful growth medium that the liquid provides. Within the past thirty years the use of radiation to kill microbes in food has been utilized. While a very effective method to ensure food safety, irradiation is still subject to consumer uncertainty, which has to date limited its usefulness. As a final example, within the past two decades, the danger posed by intestinal bacterial pathogens, particularly Escherichia coli O157:H7 has resulted in the heightened recognition of the need for proper food preparation and personal hygiene.
Food safety is also dependent on the development and enforcement of standards of food preparation, handling and inspection. Often the mandated inspection of foods requires the food to be examined in certain ways and to achieve set benchmarks of quality (such as the total absence of fecal coliform bacteria). Violation of the quality standards can result in the immediate shut down of the food processing operation until the problem is located and rectified.
Most of the food safety legislation and inspection efforts are aimed at the processing of food. It is difficult to monitor the home environment and to enforce codes of hygiene there. Yet, food safety in the home is of paramount importance. The improper storage of foods prepared with raw or undercooked eggs, for example, can lead to the growth of microorganisms in the food. Depending on the microbe and whether toxins are produced, food poisoning or food intoxication can result from eating the food dish. Additionally, improper cleaning of cutting and other preparation surfaces can lead to the cross-contamination of one food by another. Good hygienic practices are as important in the home as on the farm, in the feedlot, and in the processing plant.
