nnChap8.pptxLIVING WITH THE EARTH
CHAPTER 8
FOODBORNE ILLNESS
FOODBORNE ILLNESS
Objectives for this Chapter
A student reading this chapter will be able to:
1. Recognize, list, and explain the major reasons for food protection programs.
2. List and describe the major categories and subcategories of agents causing foodborne illness.
3. Describe the major foodborne pathogens including parasitic,viral, and bacterial diseases.
Objectives for this Chapter
A student reading this chapter will be able to:
4. Explain the mechanisms by which these pathogens cause foodborne illness, and describe how the life cycles of these organisms are important in this transmission of disease.
5. List and describe the major disease symptoms in humans for these foodborne pathogens.
Objectives for this Chapter
A student reading this chapter will be able to:
6. Describe and explain the HACCP system in protecting against foodborne disease.
7. Discuss recent regulatory efforts in the area of food potection.
FOODBORNE ILLNESS
Worldwide Distribution of Foodborne Pathogens
1.5 billion children under the age of five suffer from diarrhea, and tragically, over 3 million die as a consequence.
FOODBORNE ILLNESS
Reasons for varying prevalence among geographic regions
Climate
Population demographics
Nutritional status
Cultural aspects
Reason for Food Protection Programs
The implementation of programs to minimize foodborne diseases is important because of the problems associated with morbidity, mortality, and economic loss.
Morbidity and Mortality Due to Foodborne Disease
In the United States there are as many as 33 million cases of foodborne illness which are responsible for an estimated 9 thousand deaths annually.
Morbidity and Mortality Due to Foodborne Disease
The causative agents and modes of transmission (means through which an causative agent is spread) are known in less than 1% of the severe gastroenteritis cases.
Economic Consequences of Foodborne Illness
Medical Costs
Loss of Wages
Recall
Investigation
Litigation (Fig. 8-1)
Fig. 8-1
CAUSATIVE AGENTS OF FOODBORNE DISEASE
Foodborne illness is defined as any illness incurred from the consumption of contaminated food.
CAUSATIVE AGENTS OF FOODBORNE DISEASE
Radionuclides
Chemicals
Food Additives
Poisonous Plants and Animals
Pathogens (Table 8-1)
Table 1a
Table 1b
Radionuclides
Radiation is introduced into the food chain naturally from mineral deposits beneath the earth’s surface or from the atmosphere in the form of ultraviolet and cosmic rays.
Radionuclides
Radionuclides, which are deposited in the environment accidentally, or intentionally, as a direct result of human activity are of much greater concern.
Chernobyl
India vs. Pakistan
Chemicals
Ironically, man is responsible for many chemical contaminants presently found in food.
Between 80%-90% of our exposure to potentially harmful chemicals is from food consumption.
Chemicals
Chemicals enter the food from packaging materials, agricultural applications of pesticides and fertilizers, by adding preservatives or colorings to foods, or by the release of industrial chemicals into the environment (Table 8-2).
Table 8-2
Packaging Materials
Acidic conditions will leach these chemicals from damaged packaging containers
Antimony
Cadmium
Lead
Symptoms
Antimony
Complications of the gastrointestinal, cardiovascular, and hepatic systems
Cadmium
Kidney damage
Lead
Neurological, kidney failure, bone integrity
Industrial Processes
Mercury
Methyl mercury is an acute toxin which causes tremors, neurological complications, kidney failure, and birth defects.
Fungicides and animal feed
Minamata Bay, Japan
Industrial Processes
Polychlorinated biphenyls (PCBs)
Widely used in industry, they are extremely stable compounds that do not degrade easily, they are resistant to heat, and they are also highly toxic.
Polychlorinated biphenyls (PCBs)
Rice oil-Japan, 1968
1000 with Symptoms
Swelling of the eyes, rash, and gastrointestinal illness, five deaths.
Pesticides
Organochlorine compounds such as DDT and chlordane, organophosphates such as parathion and malathion, and inorganic compounds such as arsenics, have been have all been applied to food in the form of a pesticide.
Pesticides
Many of the chemicals banned from use in the United States are sold to developing nations who use them extensively in producing crops for export to the American market.
Pesticides
The EPA has banned DDT, aldrin, dieldrin, hepaclor, and kepone, yet traces of these compounds and their metabolites continue to be found in our food.
DDT and other chemicals of it’s class accumulate in the environment.
Food Additives
Food additives are intentionally added to food to alter taste, color, texture, nutritive value, appearance, and resistance to deterioration.
Food Additives
Food additives are considered to be the least hazardous source of foodborne illness, ranking behind pesticides, environmental contaminants, natural toxins, and microbial toxins.
Food Additives
Food and Drug Act of 1906
In 1958, the Food Additive Amendment to the Food Drug and Cosmetic Act required FDA approval before use.
Color Additive Amendment of 1950
Food Additives
Saccharin
Causes bladder cancer in lab animals
Not covered under the Delaney clause
Food Additives
Monosodium Glutamate
Chinese Restaurant Syndrome (headaches and possible nausea), and lesions of the retina.
An allowable daily intake (ADI) of 120mg/kg has been established for individuals over one year of age.
Food Additives
Nitrates and Nitrites
Prevent the growth of Clostridium spores.
In the body, nitrates can be reduced to nitrites which in turn oxidize hemoglobin and cause anoxia.
In food, nitrites react with amines, to form nitrosamines.
Have caused cancer of the liver, kidney, bladder, stomach, and pancreas of laboratory animals.
Food Additives
GRAS (Generally Recognized as Safe)
GRAS substances are chemicals that had a history of safe use before the 1958 Food Additive Amendment passed.
There are approximately 700 GRAS substances.
Currently, the FDA is reviewing their safety and reclassifying if necessary.
Poisonous Plants and Animals
By the process of trial and error, humans have identified plants that were either harmful to man, or possessed little nutritional value, and excluded them from our diet.
Some plants and animals known to be harmful to man have a significant nutritional value and are still part of our diet.
Poisonous Plants and Animals
Plant Sources
Alkaloids
Herbs -the pyrrolizidine group
Potatoes- Solanum alkaloids
Caffeine, teas- Xanthine alkaloids
Plant Sources
Lectins
Lectins are plant proteins(the Leguminosae family) that agglutinate red blood cells.
Saponins
Saponins are glycosides that hemolyze red blood cells.
As we are experiencing dietary shift to healthier foods such as alfalfa and soy based products, we can also expect an increase of saponin intoxications.
Animal Sources
Paralytic Shellfish Poisoning
Shellfish become toxic to humans when they feed on dinoflagellates such as Gonyaulax catenella in numbers greater than 200/ml of water.
Symptoms include a tingling or burning sensation of the lips and gums, ataxia, and paralysis of the diaphragm.
FOODBORNE PATHOGENS
More than 40 potential foodborne pathogens have been listed by CAST (Table 8-3).
Table 8-3
FOODBORNE PATHOGENS
Listed below are reasons for the surfacing of new and old pathogens.
Decrease in lactic acid bacteria
Contaminated water applied to food
Abuse of Antibiotics
Dietary shift
Longer shelf-life, ready-to-eat
FOODBORNE PATHOGENS
Parasitic Infections
The Nematodes
Trichinella spiralis (Fig. 8-2)
Taenia solium (Fig. 8-3)
Taenia saginata (Fig. 8-4)
Fig. 8-2 Trichinosis life cycle
Fig. 8-3a
Taenia solium
life cycle
Fig. 8-3b
Taenia solium
life cycle
Fig. 8-4a
Taenia saginata
life cycle
Fig. 8-4b
Taenia saginata
life cycle
The Protozoans
Entamoeba histolytica (Fig. 8-5a-b)
Affects about 10% of the worlds population.
Outbreaks occur where sanitation is poor, risky sexual habits are practiced, and in institutional facilities.
Symptoms Range from mild diarrhea to amoebic dysentery.
Fig. 8-5a
Entamoeba histolytica
life cycle
Fig. 8-5b
Entamoeba histolytica
life cycle
The Protozoans
Giardia lamblia
Giardia lamblia is a protozoan flagellate found in areas with poor sanitation, and in unfiltered surface water supplies (Fig. 8-6).
Giardiasis is most common among those who travel to endemic areas, in homosexuals, and in child day care settings.
Fig. 8-6
Giardia lamblia
Cysts reach the surface water supplies through the fecal deposits of beaver and muskrats
Symptoms consist of nausea, explosive diarrhea (up to ten movements per day), and fatigue.
The Protozoans
Cryptosporidium
Primarily a waterborne pathogen, Cryptosporidium is transmitted via water contaminated with feces from human and agricultural origins.
Milwaukee, 1993
Cryptosporidium
Foodborne transmission of Cryptosporidium occurs via the fecal-oral route, usually from careless food handlers shedding the hardy oocysts (see life cycle, Fig. 8-7) of the organism.
Fig. 8-7
Cryptosporidium
life cycle
Cryptosporidium
In healthy individuals, symptoms present as mild diarrhea, nausea, cramps, and a low grade fever.
Immunocompromised patients such as those with AIDS, experience high volume diarrhea, weight loss, and severe abdominal cramps.
FOODBORNE PATHOGENS
Viruses
microscopic particles that usually contain a single strand of RNA
Require a host cell for replication to occur.
The two most prominent foodborne viruses of present day are Hepatitis A and Norwalk-like virus.
Viruses
Hepatitis A
Transmitted via the fecal-oral route, and causes liver infection occasionally accompanied by jaundice.
Contamination occur by infected food workers handling foodstuffs, or from food products that have come in contact with water polluted with fecal matter.
Viruses
Norwalk-like Virus
In 1982, Norwalk-like viruses were the leading cause of reported foodborne illness in the United States, responsible for 5000 cases from two different outbreaks.
Viruses
Norwalk-like Virus
Food products such as creams, cream fillings, and salads, are efficient vehicles for viruses because they do not undergo any extensive heating before being served.
Symptoms include diarrhea and nausea
FOODBORNE PATHOGENS
Fungi
Fungi, such as molds and yeasts are single and multi-celled plant-like organisms that grow on cereals, breads, fruits, vegetables, and cheeses (Fig. 8-8).
Fig. 8-8
FOODBORNE PATHOGENS
Fungi
The majority of molds are aerobes.
Yeasts are facultative anaerobes.
Mycotoxins are mold metabolites produced on food, which cause illness or death when ingested by man or animals.
Fungi
Aspergillus flavus (Fig. 8-9)
Turkey X Disease
Four primary aflatoxins, B1, B2, G1, and G2, which are found in peanuts, corn, and cotton seed.
Causes hemorrhaging, anemia, ataxia, hematosis, cirrhosis of the liver, and is a very potent carcinogen.
Penicillium spp. (Fig. 8-9)
Rubratoxin, patulin, and yellow rice toxins are produced by members of the genus Penicillium.
Symptoms include vomiting, difficulty breathing, low blood pressure and respiratory arrest.
Mucor and Rhizopus spp. (Fig. 8-9)
Mucormycosis is the disease caused by fungi in the order Mucorales.
common spoilage organisms of bread and fruit.
Symptoms include the invasion of blood vessels, causing embolisms and tissue necrosis.
Fig. 8-9
FOODBORNE PATHOGENS
Bacteria
Bacteria are the single-celled organisms which are responsible for more than 80% of foodborne illness.
Two broad groups of bacteria classification are:
gram-positive
gram-negative.
FOODBORNE PATHOGENS
Bacteria
Bacteria exist in the form of coccus, rods, spirillium, spirochete, and appendaged (Fig. 8-10).
Fig. 8-10
Bacteria
Another characteristic useful in identifying bacteria is the ability to grow in the presence or the absence of oxygen (Fig. 8-11).
Aerobic bacteria
Anaerobic
Facultative anaerobe
Microaerophilic
Fig. 8-11
Bacteria
If the anaerobe Clostridium botulinum is suspected, the investigator might search for endospores, which are structures produced during the life cycle of certain bacteria (Fig. 8-12).
Fig. 8-12
Bacteria
Salmonella spp.
Gram-negative, facultative anaerobes.
Estimated 2-4 million cases a year in the U.S.
Three syndromes are caused by Salmonella species, typhoid fever, enteric fever, and gastroenteritis.
Bacteria
Salmonella spp.
The disease is transmitted via food, water, and the fecal-oral route
These organisms colonize in the small intestine, causing intestinal inflammation, resulting in diarrhea, abdominal cramps, chills, fever, and vomiting, which last 1-4 days.
Bacteria
Staphylococcus spp
Staphylococcus food poisoning, caused by the gram-positive cocci, Staphylococcus aureus.
Sickness is due to the consumption of the heat stable enterotoxin, and includes nausea, vomiting, and diarrhea.
Staphylococcus aureus
Contamination occurs through the preparation of foods by infected food handlers. Foods such as creams, cream pies, potato salad, and ham have all been implicated in in outbreaks of Staphylococci food poisoning.
Bacteria
Clostridium spp.
Clostridium perfringens and Clostridium botulinum are sporeforming anaerobic bacteria found in soils throughout the world.
Clostridium botulinum
Botulism is the illness that results when C. botulinum spores germinate and produce a toxin in the food to be ingested.
By destroying the spores in foods before canning or storing products, risk of botulism can be eliminated.
Clostridium botulinum
There are seven types of C. botulinum, A-G, which are identified by the toxin they produce.
The A toxin is the most common in the United States, and has been isolated in fruits, vegetables, fish, condiments, beef, pork, and poultry.
Clostridium botulinum
Symptoms
At the onset, symptoms such as nausea, vomiting and diarrhea, are present, then as the condition develops, fatigue, blurred vision, difficulty speaking and swallowing are experienced.
Bacteria
Campylobacter
Campylobacter species are part of the normal flora of the gastrointestinal tract of warm blooded animals.
During food processing, the intestinal tract is lacerated, allowing feces to contaminate the food.
Campylobacter
Campylobacter can survive for weeks in refrigeration at 4C
Symptoms are usually mild including nausea, vomiting, and bloody diarrhea, but in severe infections, Gullian Barre Syndrome develops, which causes neuromuscular paralysis.
Bacteria
Escherichia coli
Gram negative
E. coli organisms which are important to foodborne illness can be divided into four groups, enteroinvasive, enterotoxigenic, enteropathogenic, and enterohemorrhagic.
Escherichia coli
Enteroinvasive E. coli invade the epithelial cells of the intestine, resulting in fever, chills, and bloody diarrhea.
Enterotoxigenic E. coli are responsible for traveler’s diarrhea, produce a toxin, and exhibit cholera like symptoms.
Escherichia coli
Enteropathogenic E. coli are most commonly found among infant nurseries in developing countries.
Enterohemorrhagic E. coli, also known as E. coli O157:H7 is the result of consuming improperly cooked ground beef, raw milk, or unpasteurized apple cider.
Escherichia coli
E. coli O157:H7
Symptoms generally include, abdominal cramps, watery to bloody diarrhea, vomiting, and possibly a fever and;
Hemolytic uremic syndrome (HUS), which is the primary cause of renal failure in children.
Vibrio cholerae
Gram negative vibrio
Responsible for the disease cholera which is common among LDCs and international travelers.
In Peru, in 1991, an outbreak of cholera spread to 322,562 Peruvians.
Vibrio cholerae
Vibrio cholerae colonizes on the lining of the intestine and produces the toxin choleragen.
Symptoms present as abdominal pains, dehydration, and a characteristic diarrhea, which has been termed “rice water stool.”
Factors Frequently Cited in Foodborne Illness
1. Improperly refrigerated food.
2. Improperly heated or cooked food.
3. Food handlers who practice poor hygiene.
4. Lapse of a day or more between preparing and serving food.
Factors Frequently Cited in Foodborne Illness
5. Introducing raw or contaminated materials to a food that will not undergo further cooking.
6. Improper storage of foods at temperatures ideal for bacterial growth.
Factors Frequently Cited in Foodborne Illness
7. Failure to properly heat previously cooked foods to temperatures that will kill bacteria.
8. Cross contamination of ready to serve foods with raw foods, contaminated utensils or machinery, or through the mishandling of foods
Figure 8-13 illustrates some useful procedures for reducing food contamination.
Fig. 8-13
Hazard Analysis Critical Control Points
In response to this present threat, the federal government has mandated the implementation of hazard analysis critical control points (HACCP) strategies in the seafood, poultry, and meat industries.
Hazard Analysis Critical Control Points
There are seven key principles to the HACCP system (Table 8-4).
Table 8-4
United States Regulatory Efforts with Regard to Food Protection
On December 18, 1997, the FDA required that all seafood processors, domestic and those importing to the United States, carry out a hazard analysis of their products and processes.
United States Regulatory Efforts with Regard to Food Protection
On January 27, 1997, the USDA required meat and poultry slaughterers and processing facilities have sanitation SOPs in place, and that they also conduct generic E. coli testing.
Surveillance efforts
The Foodborne Diseases Active Surveillance Network (FoodNet)
Since January 1, 1996, it has identified outbreaks of Campylobacter in California, Salmonella in Oregon, and two outbreaks of E. coli O157:H7 in Connecticut.
