HAN475 Ch. 11

Toxins

Naturally occurring toxins, such as those from seafood and mushrooms, may be associated with foodborne illness.

Escherichia coli (E. coli O157:H7)

A pathogenic strain of E. coli Note that many E. coli strains reside harmlessly in the intestinal tract. Causes hemorrhagic colitis, linked to bloody diarrhea U.S.--73,000 cases and 61 deaths yearly Major outbreaks in restaurant chains Can be transmitted by hamburger meat

BSE

An extensive outbreak among cattle occurred in the United Kingdom beginning in 1986 Reported in 20 European countries as well as Japan, Israel, and Canada Cases have been reported in the U.S. (2003 and later). Appears to be spread among cattle by feeds that contain rendered cattle products

Antimicrobials in Meat

Antimicrobials that are similar or identical to those used by humans are employed for disease prevention and growth enhancement among animals (cattle, swine, poultry, and fish).

Pesticides in Foods

Applied to crops to reduce the impact of insects and other hazards, pesticides may leave residues that remain on food crops. Dietary sources are one of the principal means of exposure of the population to persistent organic chemicals, which include the family of organochlorine pesticides and polychlorinated biphenyls.

Four Major Categories of Food Hazards

Biological Physical (e.g., stone, glass, metal) Chemical Nutritional (presence of nutrients and other food constituents in excessive or deficient amounts that lead to disease)

U.S. Surveillance of Foodborne Illness

CDC maintains responsibility at the federal level. CDC Foodborne Diseases Active Surveillance Network (FoodNet) An active system whereby public health officials maintain frequent direct contact with clinical laboratory directors to identify new cases of foodborne illness.

Clostridium botulinum

Causes the foodborne disease botulism, a form of foodborne intoxication. Grows in an anaerobic (oxygen-free) environment and produces a potent toxin (a neurotoxin) that affects the nervous system.

Examples of Marine Toxins

Ciguatoxin Scombroid toxin Paralytic shellfish poison Puffer fish toxin

Irradiation of Foods

During the process, energy from ionizing radiation passes through foods and destroys bacteria and other pathogens. Procedure does not cause food to become radioactive. Referred to as cold pasteurization Certified as a safe method for reducing the risk of foodborne disease

Regulation of Food Safety

Food and Drug Administration (FDA) is the U.S. agency charged with regulation and enforcement of food safety. U.S. Department of Agriculture (USDA) regulates the safety of meat and poultry products.

Foodborne Illnesses Caused by Viral Agents: Hepatitis A

Foods that are associated commonly with HAV outbreaks include fruits, sandwiches made with cold cuts, dairy products, vegetables, and shellfish. Common mode for contamination of foods is by HAV-infected workers in food processing plants and restaurants. Of the 23,000 cases of hepatitis A reported in the U.S. annually, about 7% are believed to be food- or waterborne.

Variant Creutzfeldt-Jakob Disease (vCJD)

Form of the disease in humans "Has been linked causally to bovine spongiform encephalopathy, with human cases thought due to dietary exposure to BSE-contaminated tissues."

Staphyloccus aureus

Humans and animals are reservoirs. Present in the nose and in skin lesions Elaborates a toxin that is resistant to high temperatures Causes a foodborne intoxication with rapid onset Ham is a frequent vehicle

Delaney Clause

Part of the Food Additives Amendment, 1958 Prohibited the use of additives, including pesticides, that had been determined to cause cancer in human beings or animals

Seven Principles of HACCP

Perform a hazard analysis. Decide on the Critical Control Points. Determine the critical limits. Establish procedures to monitor the critical control points. Establish corrective actions. Establish verification procedures. Establish a record keeping system

Other Agents: Prions

Prions are regarded as the cause of bovine spongiform encephalopathy (BSE), a neurological disease in cattle. The course of BSE is progressive, ultimately fatal, and is potentially transmissible among cattle.

Salmonellosis

Ranked among the most frequent types of foodborne illness in the U.S. Approximately 2 to 4 million cases of salmonellosis (reported and nonreported) are estimated to occur each year in the U.S. Causes about 500 deaths each year

Food Quality Protection Act (1996)

Repealed the Delaney Clause Established the standard that a substance could not cause a lifetime incidence of more than one cancer case per 1 million exposed persons

Hazard Analysis of Critical Control Points (HACCP)

System for reducing the risk of foodborne illness Using HACCP, foods are monitored from the time of harvest to the time of consumption. Began in the 1950s

Tapeworms

Taeniasis is a parasitic disease caused by tapeworms. One form is caused by the beef tapeworm (Taenia saginata) and the other by the pork tapeworm (Taenia solium). These organisms may induce human illness following the consumption of raw or undercooked infected beef or pork

Clostridium perfringens

The CDC estimates that about 10,000 cases occur each year in the U.S. C. perfringens is anaerobic, rod-shaped, and forms spores. Occurs commonly in the environment (e.g., in soil and sediments), especially in those areas contaminated with feces Also found in the intestines of humans and animals

Generally Recognized as Safe (GRAS)

The GRAS rule permitted the use of additives that had an established history of safe use in foods.

Intentional Additives: Preservatives

The function of preservatives is to arrest the proliferation of microbes such as bacteria, yeasts, and molds in foods

Salmonella

The infection is called salmonellosis. Salmonella bacteria are: Rod-shaped Motile Gram-negative Non-sporeforming The most common serotypes in U.S. are: Salmonella serotype Enteritidis Salmonella serotype Typhimurium

Bacterial Agents

The pathogens Salmonella, Clostridium botulinum, Staphylococcus aureus, and Clostridium perfringens are bacteria--unicellular organisms that have characteristic shapes, e.g., rod-shaped (in some instances a slender, curved rod), spherical (cocci), or spiral.

Preventing Growth of Foodborne Pathogens

Thorough hand washing Prevention of cross-contamination Cooking at sufficiently high temperatures Storing cooked and vulnerable foods at proper temperatures in a refrigerator

How are Salmonella Bacteria Transferred?

To environmental surfaces at work and at home (e.g., the kitchen) from raw meats, poultry, and seafood From animal feces From contaminated water and soil

Chemically Related Foodborne Hazards

Toxins Heavy metals Pesticides, herbicides, and fungicides Veterinary medicines in meat Additives used for various purposes

Norovirus

Transmitted easily within closed environments such as cruise ships May be brought on board by passengers who fall ill just before embarking on a cruise Crew members and ship-board environmental contamination may act as disease reservoirs

Foodborne Illnesses Caused by Worms: Trichinosis

Trichinosis is a foodborne disease associated with eating meat that contains a nematode (also called a roundworm) from the genus Trichinella. The classic agent of trichinosis is Trichinella spiralis, which can be found in many carnivorous and omnivorous animals (e.g., pigs, bears, walruses, rodents, and cougars

Heavy Metals

When present in high concentrations, heavy metals can cause vomiting that occurs a few minutes to several hours (but in most cases in less than one hour) after ingestion.

Some U.S.-approved antimicrobials given to food animals:

amoxicillin penicillin bacitracin erythromycin

Intentional (direct) additives

are added to foods in order to improve their quality.

Foodborne Diseases and Infections

illnesses acquired by consumption of contaminated food . . ." Frequently and inaccurately referred to as food poisoning

Malicious additives

include substances such as poisons that saboteurs introduce into foods for various reasons.

Incidental (indirect) additives

may be present in foods as a result of unintentional contamination during packaging, storage, and handling.

Foodborne Outbreak

the occurrence of a similar illness among two or more people which an investigation linked to consumption of a common meal or food items, except for botulism (one case is an outbreak)."