Those working in the field of food safety are most concerned about microbial foodborne illness, a widespread but often unrecognized sickness that affects most people at one time or another. At least four factors are necessary for foodborne illness to occur: (1) a pathogen; (2) a food vehicle; (3) conditions that allow the pathogen to survive, reproduce, or produce a toxin; and (4) a susceptible person who ingests enough of the pathogen or its toxin to cause illness. The symptoms often are similar to those associated with the flu—nausea, vomiting, diarrhea, abdominal pain, fever, headache. Most people have experienced foodborne illness, even though they might not recognize it as such, instead blaming it on the stomach flu or a twenty-four-hour bug. Usually symptoms disappear within a few days, but in some cases there can be more long-lasting effects such as joint inflammation or kidney failure. In the most severe cases people die from foodborne illness.
Current estimates of foodborne illness in the United States United States U.S.
Factors Influencing the Safety of Food
Stories of foodborne illness have become much more prevalent throughout the world. Is food less safe than it used to be, and if so, what factors account for this? News travels fast these days, both electronically and through the news media. What were once isolated events and stories, now reach millions within hours. Diagnostic techniques are constantly improving, allowing for identification of diseases, foodborne and otherwise, that would have been of unknown origin in the past. But even considering these facts, public-health officials believe that the risk of foodborne illness has increased over the past twenty years (GAO, 1996). Some threats to food safety have been around since ancient times, while others are newer, the result of changing demographics and lifestyles, production practices, and even evolution of microorganisms themselves.
Demographics
The proportion of the population at serious risk of foodborne illness is increasing as the population ages and the number of people with weakened immune systems grows. People who are at higher risk of becoming seriously ill include infants, young children, the elderly, pregnant women, those taking certain medications, and those with diseases such as acquired immunodeficiency syndrome (AIDS), cancer, and diabetes that weaken their immune systems. Demographers predict that the proportion of people over sixty years old in industrialized countries such as the United States will rise from the current 17 percent of the population to 25 percent by 2025 (Kaferstein, 1999). In one survey, 89 percent of deaths with diarrhea as an underlying cause were adults fifty-five and over or children under the age of five (Morris, 1997).
While anybody can get sick from eating contaminated food, the severity of the illness depends on a number of factors. Most important among these are age, amount of contamination consumed, and health status of the individual. The body has a number of defenses to protect itself against harmful bacteria. The acidic gastric juices of the stomach are one of the first defenses against foodborne pathogens, as many bacteria cannot survive in an acidic environment. Very young infants and aging adults produce fewer, or less acidic, gastric juices than younger, healthy adults. The normal bacteria present in the gastrointestinal system form another protective barrier against foodborne illness by preventing harmful bacteria from colonizing the gut. Use of antibiotics, which destroy the protective bacteria normally present in the gastrointestinal tract as well as their target bacteria, make it easier for pathogenic bacteria to invade and cause illness. Finally, the human immune system, not fully developed at birth, gradually reaches maturity in puberty and then slowly begins to decline after about fifty years of age.
Consumer Lifestyles and Demand
As the pace of life quickens, we often eat meals on the run, and spend less time on food preparation, preferring instead restaurants, convenience foods, or already prepared meals. This means that by the time you eat your food, it may have been transported, cooked, cooled, stored, transported again, reheated, and touched by numerous individuals. Each processing step introduces new hazards that could allow for the survival and growth of pathogens. In the United States
Add to this the mishandling of food that occurs after a consumer purchases food and takes it home, and the likelihood of illness increases. Approximately 20 percent of reported foodborne illness cases occur from food cooked at home. Experts believe that this number is actually much higher, but that most people do not report cases of illness caused by foods cooked at home (Knabel, 1995; Doyle, 2000). As people cook less, they pass on less knowledge of cooking to their children, who are nevertheless increasingly responsible for preparing meals. This has grave implications for the future of food safety. In a survey of consumer food safety knowledge and practices, 86 percent of respondents knew that they should wash their hands before preparing food, but only 66 percent reported actually doing so. Only 67 percent of respondents reported washing or changing cutting boards after cutting raw meat or poultry. Older adults practiced safe behaviors more often than did younger adults (Altekruse, 1995). In an Australian study in which researchers asked people about their food safety and kitchen habits, and then filmed them preparing food, there were large differences in what people said they did and what they actually did. Almost half the people who said they washed their hands after handling raw meat did not, and when they did it was often without soap. Nineteen percent of the households that claimed to have soap in the kitchen did not (Jay, 1999).
Consumers are increasingly demanding fresh and natural products, prepared with fewer preservatives. Without the traditional preservatives and processing methods that prevent microbial growth, modern all-natural and fresh products are more perishable. Food processing, mainly canning, freezing, and pasteurizing, not only extends the shelf-life of foods, but also inhibits bacterial growth, making food safer. As an example, fresh apple cider has been associated with several foodborne disease outbreaks. An outbreak of Escherichia coli O157: H7 in which a child died was associated with raw unpasteurized apple juice from a company that built its reputation on the naturalness of its products.
As the role of fresh fruits and vegetables in a nutritious diet has become evident, people are including them in their diet more. In 1993 Americans ate 27 percent more fresh produce than they did in 1973. An increase in the number of foodborne illness outbreaks associated with fresh produce has accompanied this increase in consumption. In the last twenty years of the twentieth century, the number of identifiable outbreaks in which produce was the food vehicle doubled (Tauxe et al., 1997). Most produce only grows in the United States Canada Guatemala United States
Food Production and Economics
In the past, outbreaks of foodborne illness were relatively small and local. Illness could be traced back to local events such as weddings, church dinners, and other gatherings where a large number of people ate the same food. Today's food is produced in vastly different ways from those of even several decades ago. Food used to be grown, produced, and distributed on a local basis. Food production is now centralized and on a larger scale than in the past. Products made in a single processing plant in mass quantities are shipped all over the country, sometimes throughout the world. A mistake made in the processing will be felt nationwide instead of just locally. In 1994 an estimated 224,000 people throughout the nation became ill from Salmonella enteritidis after eating ice cream produced at one ice cream processing facility in Minnesota
Even the manner in which farmers raise animals can contribute to an increase in food safety problems. A large number of animals are often crowded together, increasing their stress levels and weakening their immune systems. This crowding also facilitates the spread of disease from one animal to another. In the old days a sick animal would be fairly isolated and if it became sick it would not pass on illness to the rest of the flock or herd. But with closer animal-to-animal contact, disease can quickly spread throughout the whole group.
New and Evolving Pathogens
As recently as fifty years ago scientists had identified four foodborne pathogens. Today five times that number are on the list. Twenty years ago scientists did not even recognize three of the four pathogens that the Centers for Disease Control considers the most important in causing foodborne illness—Campylobacter jejuni, Listeria monocytogenes, and E. coli O157:H7. C. cayetanensis first appeared in 1979 and is still not well understood. It is likely that scientists will discover new foodborne pathogens as laboratory techniques improve.
As living organisms, pathogens are constantly evolving. With better ability to trace outbreaks, scientists are discovering that some bacteria survive in environments previously thought safe. For example, E. coli O157:H7, originally called "hamburger disease" because of its presence in undercooked ground beef, has shown up in foods as diverse as salami, apple cider, raw milk, and lettuce. It also survives in lower pH conditions than originally thought, leading to the outbreaks in acidic foods such as salami and apple cider. It is now known that Yersinia enterocolitica and L. monocytogenes can survive and multiply at refrigeration temperatures.
Some foods long considered safe have recently been implicated in foodborne outbreaks. For years scientists believed the inside of an egg was sterile and that Salmonella enteritidis was not of concern. Now however, they know that chickens infected with Salmonella pass this infection along in their eggs, so that the bacteria can be found inside the raw egg, making it unsafe to eat raw or undercooked eggs. This was not known until 1989. Knowledge of this fact caused food safety experts to advise people to cook eggs thoroughly or to use liquid pasteurized eggs.
Bacteria have long been capable of evolving to thwart attempts to eliminate them. Some pathogens are now becoming resistant to common antimicrobial agents. It is thought that the resistance may be related to the sub-therapeutic use of these antibiotics in animals. We are seeing this same adaptability in foodborne bacteria. Salmonella typhimurium DT104 is widely distributed in wild and farm animals, especially in Europe , and is resistant to several common antibiotics. There has been a parallel increase with people getting sick from this type of drugresistant Salmonella.
History of Food Safety
Very little about foodborne illness or food safety is found in historical records. Scientists did not begin to understand bacteria, and their relationship to disease, until the late nineteenth century. People did recognize that food spoils, but the reasons for that and the potential for becoming ill from food were not known. The history of food safety is really the history of the numerous discoveries, inventions, and regulations that all led to the present knowledge.
Food preservation methods such as drying, smoking, freezing, marinating, salting, and pickling have their beginnings thousands of years ago. Whether these methods were employed solely to keep food for later use, to improve flavor, or for other reasons is not known; but for whatever reason they were developed, they also had the effect of keeping food safer. Even cooking can be viewed as an ancient method of making food safer. The Chinese Confucian Analects of 500 B.C.E. warned against consumption of sour rice, spoiled fish or flesh, food kept too long, or insufficiently cooked food. The Chinese disliked eating uncooked food, believing that anything boiled or cooked cannot be poisonous. It is possible that the practice of drinking tea originated because tea required using hot water, which would make it safer than using unheated contaminated water (Trager, 1995). Doubtless other cultures in antiquity, while oblivious to the causes or prevention of foodborne disease, experienced it and prescribed methods to avoid it.
Much of the present knowledge about pathogens and foodborne illness is built on a foundation of scientific discoveries spanning back over three centuries. Italians Francisco Redi and Lazzaro Spallanzani performed experiments that dispelled the theory of spontaneous generation of organisms. The discovery of bacteria in the late nineteenth century, the increased understanding of bacteria's role in disease, and the realization that there is a connection between human diseases and animal diseases led to the ideas that cleanliness is important and that unsanitary conditions can contribute to disease. A leader in this effort was Hungarian physician Ignaz Semmelweiss, who in 1847 required hospital doctors to wash their hands before delivering babies. As a result, maternal death rates plummeted from 10 to 1.5 percent. His colleagues greeted his theory that doctors were carrying disease from person to person with ridicule. Instead they attributed maternal deaths to a phenomenon arising from the combustible nature of pregnant women. Lack of personal hygiene remains one of the main causes of foodborne illness 150 years later.
Louis Pasteur further elucidated the link between spoilage, disease, and microorganisms with his work on fermentation and pasteurization in the 1860s and 1870s. In 1872 German scientist Ferdinand Julius Cohn published a three-volume treatise on bacteria, essentially founding the science of bacteriology. But this new field of bacteriology needed bacteria on which to conduct experiments and study. It took Robert Koch in the 1880s to perfect the process of growing pure strains of bacteria in the laboratory. At first he used flat glass slides to grow the bacteria. His assistant, Julius Richard Petri, suggested using shallow glass dishes with covers, now commonly called Petri dishes. Koch also established strict criteria for showing that a specific microbe causes a specific disease. These are now known as Koch's Postulates. Using these criteria scientists can identify bacteria that cause a number of diseases, including foodborne diseases. In 1947 Joshua Lederberg and Edward Lawrie Tatum discovered that bacteria reproduce sexually, opening up a whole new field of bacterial genetics (Asimov, 1972).
Even though Antonie van Leeuwenhoek, a Dutch biologist and microscopist, had improved the microscope to the degree that small microscopic organisms could be seen as far back as 1673, the discovery of foodborne disease causing microorganisms developed slowly. Although James Paget and Richard Owen described the parasite Trichinella spiralis for the first time in 1835, and German pathologists Friedrich Albert von Zenker and Rudolph Virchow noted the clinical symptoms of trichinosis in 1860, the association between trichinosis and the parasite Trichinella spiralis was not realized until much later. The English scientist William Taylor showed in 1857 that milk can transmit typhoid fever. In 1885, United States Department of Agriculture (USDA) veterinarian Daniel Salmon described a microorganism that caused gastroenteritis with fever when ingested in contaminated food. The bacteria was eventually named Salmonella (Asimov, 1972). August Gärtner, a German scientist, was the first to isolate Bacillus enteritidis from a patient with food poisoning, in 1888. The case was the result of a cow with diarrhea slaughtered for meat; fifty-seven people who ate the meat become ill (Satin, 1999). Emilie Pierre-Mare van Ermengem, a Belgian bacteriologist, was the first to isolate the bacteria that causes botulism, Clostridium botulinum, in 1895. The case concerned an uncooked, salted ham served at a wake in Belgium Philippines
Food Safety Regulations
The earliest food safety regulations in the United States Massachusetts
The year 1906 was an important one for federal food safety regulation with the passage of both the Pure Food and Drug Act and the Federal Meat Inspection Act. The public was fed up with shocking disclosures of unsanitary conditions in meatpacking plants and the use of poisonous preservatives and dyes in foods. In A Popular Treatise on the Extent and Character of Food Adulterations consumers read that almost every food they purchased was adulterated or mislabeled. The Poison Squad, a group of USDA chemists formed in 1902 to study preservatives used in food products by eating the foods themselves, revealed that many of the chemicals used in food production were harmful to human health. Upton Sinclair's 1906 novel, The Jungle, highlighted the horrible working conditions of the nation's working class by describing in lurid detail the filthy conditions and adulteration of meat that was common in the Chicago
The Federal Meat Inspection Act protected consumers by "assuring that meat and meat food products are wholesome, not adulterated, and properly marked, labeled, and packaged." The act established sanitary standards and mandated continuous inspection of cattle, sheep, goats, and equines before, during, and after slaughter. The 1906 Pure Food and Drug Act forbade the adulteration of foods, drinks, and drugs in interstate commerce. Foods were considered misbranded if they were labeled so as to deceive the public, if the contents in terms of weights and measures were either incorrect or not present on the package, or if the label contained any false or misleading statement concerning the ingredients of a food.
Although it was a good start, the Pure Food and Drug Act had some very large flaws. Since it did not set standards as to what exactly should be in a particular food, it was almost impossible to prove adulteration of a food. For example, without knowing how much strawberry was supposed to be in strawberry jam, federal lawyers could not prove that a product with almost no strawberry in it was not strawberry jam. The act required the government to prove that offenders intended to deceive or poison consumers with their product. When brought to court defendants pleaded ignorance of the results of their actions. These deficiencies led to a renewed push for regulatory reform in the 1930s.
In 1933 Arthur Kallet and F. J. Schlink published the immensely popular book 100,000,000 Guinea Pigs: Dangers in Everyday Foods, Drugs and Cosmetics. Written in true muckraking style, it stirred the public's ire at the condition of the food they were eating. The basic premise of the book was that the federal government was unable to protect consumers from bad food and drugs, both due to incompetence and to the lack of adequate laws.
As with passage of the 1906 act, public opinion played a strong role in sending the message to Congress that reform was needed. Since much of the media sided with the food manufacturing industry against reform, the Food and Drug Administration (FDA) took its message directly to the people, speaking at women's clubs, to civic organizations, and on the radio. The FDA collected hundreds of products (both food and drug) that had injured or cheated consumers, emphasizing that the 1906 act did not regulate these products enough to prevent such occurrences. The exhibits were photographed and converted into posters to illustrate the need for new laws. They were displayed at FDA talks and at a museum in FDA headquarters. The exhibit was christened the "Chamber of Horrors," leading to the publication of The American Chamber of Horrors by the FDA's Chief Educational Officer, Ruth deForest Lamb, in 1936. Ms. Lamb recounted some of the little-known, and sickeningly lurid, behind-the-scenes details of the food industry. In arguing the need for a new food and drug law, she noted that the 1906 laws were outdated due to new modes of living, new kinds of products, new methods of manufacturing and selling, new tricks of sophistication, and new scientific discoveries, all demanding a more modern method of control.
Finally, in 1938, Congress passed the Federal Food, Drug, and Cosmetic Act (FDCA). This act, with a number of adjustments and amendments, is still the major force regulating foods. It continued with many of the intentions of the 1906 act, but broadened the scope of federal regulation and plugged many of the loopholes. For the first time the law defined adulteration to include bacteria or chemicals that are potentially harmful; allowed the FDA to inspect food manufacturing and processing facilities; required ingredients of nonstandard foods to be listed on labels; prohibited the sale of food prepared under unsanitary conditions; gave the FDA the authority to monitor animal drugs, feeds, and veterinary devices; and authorized mandatory standards for foods. Few laws have as great an impact on the life and health of Americans as does the Food, Drug, and Cosmetic Act. The overall function of the law was to prevent the distribution of harmful or deceptive food and drug products.
Seafood regulation came about on a voluntary basis with the Seafood Inspection Act of 1934. In the early 1930s, canned shrimp processors found that the FDA was seizing increasingly large amounts of their product because of decomposition. Poor fishing practices and poorly supervised packing operations contributed greatly to the spoilage of shrimp products. As the canners could not themselves influence fishermen and packers to improve their handling of the product, they requested that Congress enact an inspection law. Packers of any seafood product could request an inspector to examine the premises, equipment, methods, containers, and materials used. If the inspection was favorable, they could use that information on their label. The new seafood inspection program had an almost immediate favorable effect on the canned seafood industry. Product quality improved and the industry was able to regain consumer confidence in its product.
In August 1996, Congress signed into law the Food Quality Protection Act (FQPA), fundamentally changing the way the Environmental Protection Agency (EPA) regulates pesticides used in the production of food. The FQPA sets special provisions concerning pesticide ingestion for infants and children. Because little data exist on pesticide intake for children, an additional safety factor of up to tenfold, if necessary, is to be used. All existing tolerances are to be reviewed within ten years, and consideration of children's special sensitivity and exposure to pesticide chemicals must be taken into account when setting tolerance levels. The EPA is now required to periodically review pesticide registrations, with a goal of establishing a fifteen-year cycle, to ensure that all pesticides meet updated safety standards. Most importantly, the new law establishes a health-based safety standard for pesticide residues in all foods. It uses "a reasonable certainty that no harm" will result from all combined sources of exposure, including drinking water, as the general safety standard. This last facet of the FQPA is perhaps the most important because it eliminates the Delaney Clause of the Food, Drug, and Cosmetic Act, which prohibited the addition of any cancer-causing substance, no matter how small the amount, from being added to foods.
Hazard Analysis and Critical Control Points (Haccp)
In 1996 USDA issued its Pathogen Reduction: Hazard Analysis and Critical Control Points (HACCP) System rule. This rule requires that all 6,500 meat and poultry processing plants in the United States
Since the passage of the Meat Inspection Act in 1906, inspectors had visually examined and smelled meat to determine if it was safe or not. Such methods are not effective against the main threat to the safety of food today—bacteria so small that they cannot be seen or smelled. The failure of inspection methods in the United States came to the fore in 1993 when an outbreak of E. coli O157:H7 in hamburgers in the northwestern United States sickened over five hundred people and killed four. This provided the final push needed for the U.S. Department of Agriculture (USDA) to issue the Pathogen Reduction: Hazard Analysis and Critical Control Points (HACCP) System rule in 1996. Under HACCP regulations, the food processing industry assumes primary responsibility for the safety of the food it produces. The government's role is to verify that the industry is carrying out its responsibility, and to initiate appropriate regulatory action if necessary.
HACCP started from a National Aeronautics and Space Administration (NASA) food safety program in the 1960s. NASA needed to come as close as possible to 100 percent assurance that the foods astronauts consumed while on space missions would be free of bacterial or viral pathogens. NASA, the U.S. Army Natick Laboratories, and the Pillsbury Company began to develop these first space foods. While Pillsbury researchers struggled with problems such as how to keep food from crumbling in zero gravity, they also realized that traditional food quality control programs would not provide the degree of safety desired. To produce the safest food possible, they needed to have control over their production process, the raw materials, the environment, and their employees. To provide this level of control, in 1971 they introduced the HACCP system.
A typical HACCP system identifies critical points during food processing where contamination is likely to occur.Then, controls can be put in place to focus on these critical areas. Traditionally, industry and regulators depended on spot-checks of manufacturing conditions and random sampling of final products to ensure safe food. This approach, however, tends to be reactive, rather than preventive. HACCP is a preventive, systematic approach to food safety, rather than a reactive method. One key advantage of HAACP is that it focuses on identifying and preventing hazards that may contaminate food, thereby allowing control to be exerted in the manufacturing phase, rather than after food is produced. HAACP permits more efficient and effective government regulation, primarily because record keeping allows investigators to see how well a firm is complying with food safety laws over a given extended period rather than only on a given day. HACCP has achieved international recognition as the most effective means of controlling foodborne disease. The National Academy of Sciences, the joint Food and Agriculture Organization/World Health Organization Codex Alimentarius Commission, and the U.S. National Advisory Committee on Microbiological Criteria for Foods (NACMCF) all endorse the use of HACCP.
HACCP involves seven principles:
- Analyze potential hazards (biological, such as a microbe; chemical, such as a toxin; or physical, such as ground glass or metal fragments) associated with a food and determine measures to control those hazards.
- Identify critical control points in the production of a food—from its raw state through processing and shipping to consumption—at which it is possible to control or eliminate the potential hazard. Examples are cooking, cooling, packaging, and metal detection.
- Establish preventive measures with critical limits for each control point. For a cooked food, this might include setting the minimum cooking temperature and time required to ensure elimination of harmful microbes.
- Establish procedures—such as how cooking time and temperature should be checked, and by whom—to monitor critical control points.
- Establish corrective actions to be taken when monitoring shows that a critical limit has not been met—for example, reprocessing or disposing of food if the minimum cooking temperature is has not been attained.
- Establish procedures to verify that the system is working properly—for example, testing time and temperature recording devices to make sure that a cooking device is working properly.
- Establish effective record keeping to document that the HAACP system is working properly, by maintaining records of hazards, methods to control them, monitoring to ensure safety requirements are met, and actions taken to control potential problems.
To protect the public from foodborne illness, more and more of the U.S.
Food Safety At the International Level
Several international organizations interact to improve the safety of the world's food supply. The Food and Agricultural Organization (FAO) was founded as part of the United Nations in 1945 to raise levels of nutrition and standards of living, to improve agricultural productivity, and to better the condition of people in rural areas. Food safety is an important part of FAO's mission since foodborne disease is one of the most widespread threats to human health, as well as an important cause of reduced economic productivity. The World Health Organization (WHO), founded in 1948, has as its mission to set global standards of health and to aid governments in strengthening national health programs. WHO recognizes that protecting consumers from contaminants and preventing foodborne diseases are two of the most important strategies for overcoming malnutrition in the world. WHO's activity in food safety issues centers around development of national food safety policies and infrastructures, food legislation and enforcement, food safety education, promotion of food technologies, food safety in urban settings and in tourism, surveillance of foodborne diseases, and monitoring of chemical contaminants in food. FAO and WHO collaborate on many food safety issues as joint FAO/WHO committees and conferences.
One of the most important joint FAO/WHO commissions is the Codex Alimentarius Commission. This body has as its task the development of uniform food standards that can be used by governments throughout the world. This food code is known as the Codex Alimentarius. The Codex Alimentarius consists of food standards for commodities, codes of practice for hygiene and technology, pesticide evaluations and limits for pesticide residues, evaluations of food additives, guidelines for contaminants, and evaluations of veterinary drugs. Although the main goal of the Codex is to set uniform regulatory standards in the interests of international trade, it has also served to raise food safety standards in many countries. One hundred forty member nations accept its standards and follow its codes of practice.
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