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Toxins in Everyday Life - Toxins In Food

organic pathogens percent foodborne

Chemicals and Pesticides

Noncommercially caught fish and wildlife are sometimes contaminated with chemicals, such as mercury, PCBs, and DDT. In order to protect consumers from health risks associated with consuming such pollutants, the EPA and the states issue consumption advisories to inform the public that high concentrations of contaminants have been found in local specimens. According to the EPA in Update: National Listing of Fish and Wildlife Advisories (May 2003), in 2002 (the latest year for which data are available), 2,800 advisories were in effect.

The total number of lake areas and river miles under advisory for various pollutants between 1993 and 2003 is shown in Figure 8.12 and Figure 8.13. All five of the specific contaminants listed are bioaccumulative, meaning that they accumulate in the tissues of aquatic organisms at much higher concentrations than are found in the water. These contaminants also persist in the environment for a relatively long time.

The GAO report Information on EPA's Draft Reassessment of Dioxins (April 2002) provided the EPA's estimates of the average U.S. adult's exposure to dioxins in food on a daily basis. (See Table 8.7.) Beef and freshwater fish and shellfish are the major sources of exposure. These levels are associated with adverse health effects, but are below the levels associated with cancer. Levels of exposure are thought to be even greater in people who have diets high in fat content.

Pathogens

According to federal officials, the U.S. food supply is among the safest in the world. Nevertheless, episodes of food poisoning and diseases occur in the United States. Based on "Food-Related Illness and Death in the United States" by Paul S. Mead et al. (Emerging Infectious Diseases, vol. 5, no. 5, 1999), the CDC estimates that as many as 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths annually are caused by foodborne hazards. Unfortunately, most of the incidences cannot be traced to a particular pathogen, but are attributed to "unknown" agents. Known pathogens are associated with 14 million illnesses, 60,000 hospitalizations, and 1,800 deaths annually. Three pathogens, Salmonella, Listeria, and Toxoplasma, are blamed for more than 75 percent of the deaths.

Foodborne illnesses became the object of intense public scrutiny following an outbreak of Escherichia FIGURE 8.12
Trends in number of lake acres under advisory for various pollutants, 1993–2002
coli (E.coli) in 1993 that killed four people and sickened hundreds. The illness was attributed to undercooked hamburgers from fast-food restaurants. The FDA responded by raising the recommended internal temperature for cooked hamburgers to 155 degrees Fahrenheit. A sampling program was begun to test for E. coli in raw ground beef. New labels containing food handling instructions were required on consumer packages of raw meats and poultry.

In 1996 more illnesses were attributed to E. coli, this time in unpasteurized apple juice. The FDA proposed new regulations to improve the safety of fresh and processed juices. In that same year several federal and state agencies established a surveillance program called FoodNet to monitor laboratory-identified foodborne diseases related to seven pathogens in parts of five states. By 2002 the program had grown to monitor 12 pathogens and syndromes in nine states, encompassing 37.4 million people (13 percent of the U.S. population). FoodNet data for 2002 are presented in Table 8.8.

FoodNet identified 16,580 cases of foodborne illnesses related to monitored pathogens in 2002. Salmonella accounted for 36 percent of cases, followed by Campylobacter (30 percent), and Shigella (23 percent).

The incidence of diseases attributed to Listeria, Yersinia, and Campylobacter decreased dramatically between 1996 and 2002. The CDC attributes the decline to several factors including increased public awareness about foodborne diseases and food safety, new pathogen FIGURE 8.13
Trends in number of river miles under advisory for various pollutants, 1993–2002
reduction measures implemented by the U.S. Department of Agriculture (USDA) at meat and poultry slaughterhouses and processing plants, egg quality assurance programs, better agricultural practices that ensure produce safety, increased regulation of imported foods and fruit and vegetable juices, and the introduction of hazard reduction measures in the seafood industry.

Eating Habits and Food Preparation

Americans have changed their eating habits, and with such changes have come additional risks. Some explanations for the high rate of foodborne illnesses include the following:

  • Americans are eating out more than in the past.
  • More and more foods are being imported from foreign countries.
  • New pathogens and strains of organisms are turning up in the food supply.
  • Many people are careless about food preparation in the home.

In 1997 the CDC found that, among the factors that contributed to the transmission of foodborne disease, improper handling temperatures caused the most cases, followed by poor personal hygiene of handlers, contaminated equipment, inadequate cooking, and food from unsafe sources.

TABLE 8.7
Environmental Protection Agency estimates of the average adult's daily exposure to dioxins -from dietary intake, picograms per day

Food type Dietary exposure to CDDs and CDFs Dietary exposure to PCBs Total dietary exposure to dioxins
Beef 9.0 4.2 13.2
Freshwater fish and shellfish 5.9 7.1 13.0
Dairy products (cheese, yogurt, etc.) 6.6 3.2 9.8
Other meats (lamb, baloney, etc.) 4.5 1.0 5.5
Marine fish and shellfish 2.5 2.4 4.9
Milk 3.2 1.5 4.7
Pork 4.2 0.2 4.4
Poultry 2.4 0.9 3.3
Eggs 1.4 1.7 3.1
Vegetable fat (oils, margarine, etc.) 1.0 0.6 1.6
Total 40.7 22.8 63.5
Note: The average adult is assumed to weigh 70 kilograms (154 pounds). A picogram is one-trillionth of a gram.
CDDs = Chlorinated Dibenzo-p-dioxins
CDFs = Chlorinated Dibenzofurans
PCBs = Polychlorinated Biphenyls
SOURCE: "Table 1. EPA's Estimates of the Average U.S. Adult's Daily Exposure to Dioxins from Dietary Intake, Picograms Per Day," in Information on EPA's Draft Reassessment of Dioxins, GAO-02-515, U.S. General Accounting Office, Washington, DC, April 2002

Contamination from Produce

The per capita consumption of fresh produce has increased in the United States in recent years. Some Americans may be eating more produce for health reasons and, because of growing commerce between nations all over the globe, a wider variety of fruits and vegetables are available today.

Researchers Larry R. Beuchat and Jee-Hoon Ryu conducted a study for the CDC of factors associated with produce contamination. As reported in "Produce Handling and Processing Practices" (Emerging Infectious Diseases, vol. 3, no. 4, 1997), they determined that contamination of produce can occur in the field or orchard, during harvesting or processing, in transport or marketing, or in the home or restaurant. The scientists categorized sources of contamination as preharvest or postharvest.

Preharvest sources include feces in soil or fertilizer, organisms in the soil, pollution of water used to irrigate or spray crops, dust and air, animals (including birds), insects, and human handling. Postharvest factors include feces, handling by workers or consumers, farm equipment, transport containers, insects, and animals. Other possible postharvest sources are air and dust, wash water, processing equipment, ice, transport vehicles, improper storage or packaging, inappropriate temperatures, cross-contamination from other foods, and incorrect handling. Beuchat and Ryu concluded: "Control or elimination of pathogenic microorganisms from fresh fruit and vegetables can be achieved only by addressing the entire system—from the field, orchard, or vineyard to the point of consumption."

Organic Foods—A Booming Industry

Some consumers are concerned about certain technologies being applied to the food supply, including irradiation, the use of hormones in milk production, and genetically engineered crops. Irradiation, in particular, is a highly controversial subject. About 40 countries worldwide use irradiation, in which food is briefly exposed to radiant energy, such as gamma rays or high-energy electrons, as a means of controlling pathogens. Some foods in the United States have been irradiated since the 1960s. (See Table 8.9.) A 2000 report on food irradiation by the GAO reported that 95 million pounds of food products were irradiated in 1999, representing about 10 percent of their total consumption. The GAO concluded that the benefits of irradiation in terms of reduced mortality, illnesses, and associated costs outweighed the minimal risks. Risks commonly attributed to food irradiation include possible creation of chemical byproducts and loss of nutritional value.

The USDA defines organic agriculture as an "ecological production management system that promotes and enhances biodiversity, biological cycles, and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain, and enhance ecological harmony." Organic agriculture is both an approach to food production based on biological methods that avoid the use of synthetic crops or livestock products, and a broadly defined philosophical approach to farming that puts value on ecology, conservation, and nonintensive animal breeding practices. Some conventional practices not accepted in organic agriculture include the following:

  • Synthetic fertilizer and pesticides
  • Confinement livestock operations such as feed lots or cages where animals are fattened before slaughter
  • Routine use of growth-enhancing animal drugs such as hormones or antibiotics
  • Genetically modified crops
  • Irradiation of foods for preservation or decontamination

While organic methods of farming emerged in the United States and Europe in the early 1900s, it was not until the late 1980s that research groups and consumers began to express widespread interest in such practices. Beginning in 1989 sales of organically produced products began to climb, growing, on average, 20 percent per year. According to the 2003 USDA report U.S. Organic Farming in 2000-2001: Adoption of Certified Systems by Catherine Greene and Amy Kremen, in 2001 sales of organic products reached approximately $9 billion in the United States and $21 billion worldwide. Organic food sales accounted for 1–2 percent of total food sales in all major world markets.

In the same report the USDA notes that there were nearly 7,000 certified organic operations in the United

TABLE 8.8
Cases of infection1 with nine pathogens and of one syndrome under surveillance in the Foodborne Diseases Active Surveillance Network (FoodNet) by selected characteristics, 2002

Syndrome California Colorado Connecticut Georgia Maryland Minnesota New York Oregon Tennessee Overall Object
Campylobacter 31.67 13.99 15.79 7.58 6.72 18.95 12.97 16.01 6.37 13.37 12.30
Escherichia coli O157 0.99 2.12 1.37 0.67 0.48 3.62 1.69 5.13 0.70 1.73 1.00
Listeria 0.37 0.12 0.47 0.18 0.43 0.10 0.45 0.26 0.11 0.27 0.25
Salmonella 15.85 13.46 13.28 21.43 17.13 11.87 16.22 9.53 19.61 16.10 6.80
Shigella 11.45 5.53 3.04 19.06 21.53 4.46 1.60 2.71 5.07 10.34 NA2
Vibrio 0.37 0.12 0.32 0.32 0.35 0.10 0.12 0.43 0.25 0.27 NA
Yersinia 0.50 0.12 0.47 0.51 0.26 0.38 0.63 0.49 0.60 0.44 NA
Cryptosporidium 0.99 0.88 0.55 1.43 0.52 4.10 1.75 1.15 0.46 1.42 NA
Cyclospora 0.05 NR3 0.20 0.27 0.05 NR 0.33 NR 0.04 0.11 NA
HUS4 1.01 2.62 1.79 0.84 NR 2.42 0.49 8.96 NR 1.78 NA
Population in surveillance (millions)5 3.20 2.46 3.43 8.38 5.38 4.97 3.32 3.47 2.84 - -
1Per 100,000 persons.
2Not applicable.
3None reported.
4Hemolytic uremic syndrome. Incidence per 100,000 children aged 5 years.
5Population for some sites is entire state, for other sites, selected countries. For some sites, the catchment area for Cryptosporidium and Cyclospora is larger than for bacterial pathogens.
SOURCE: "Incidence of Cases of Infection with Nine Pathogens and of One Syndrome Under Surveillance in the Foodborne Diseases Active Surveillance Network, by Site, Compared with National Health Objectives for 2010–United States, 2002," in Morbidity and Mortality Weekly Report, vol. 52, no. 15, April 18, 2003

States in 2001, up from 5,000 operations in 1997. The acres of farmland managed under certified systems increased by 74 percent during those years, from 1.4 million acres in 1997 to 2.2 million acres in 2001.

For most of its history the organic food industry established its own organizations and standards, with approximately 33 private certification operations. However, there was no consistency in labeling and no guarantee that foods labeled as organic are actually grown and processed in a purely organic fashion.

In 1990 Congress passed the Organic Foods Production Act (Title 21 of PL 10-624) to regulate the organic food industry. The act authorized the National Organic Program (NOP) to be administered by the USDA. The program would define standard practices and certify that operations meet those standards. It would be illegal for anyone to use the word "organic" on a product if it does not meet the defined criteria.

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