Q&A Hero

Q: Cryptosporidium parvum oocysts are highly resistant to A) heat. B) filtration. C) desiccation. D) chlorine.

Q: The microorganism Cryptosporidium parvum is a A) fungus. B) bacterium. C) protozoan. D) virus.

Q: Giardia cysts are able to withstand A) chemical disinfection. B) filtration. C) clarification. D) chemical disinfection, filtration, and clarification.

Q: The organism causing giardiasis is a A) gram-negative spirochete. B) flagellated protozoan. C) retrovirus. D) type of yeast.

Q: ALL fungal infections can broadly be termed A) benign. B) systemic. C) superficial. D) mycoses.

Q: Athlete's foot is an example of a A) protozoal infection. B) superficial fungal infection. C) superficial parasitic infection. D) hypersensitivity reaction.

Q: Many fungi produce ________ that can cause significant disease. A) cellulases B) mycotoxins C) endotoxins D) chitinases

Q: A common mechanism in fungal diseases is A) endotoxin production. B) intracellular invasion. C) hypersensitivity reactions. D) red blood cell lysis.

Q: The MOST serious types of fungal infections are A) subcutaneous infections. B) mycotoxic infections. C) systemic mycoses. D) superficial mycoses.

Q: Which of the following are malaria vaccines currently in development? A) synthetic peptide vaccines B) recombinant particle vaccines C) DNA vaccines D) synthetic peptide, recombinant particle and DNA vaccines

Q: Which of the following human mutations correlates with resistance to plasmodial infections in West Africa? A) hemoglobin S B) one particular MHC class I gene C) one particular set of MHC class II genes D) hemoglobin S and particular class I and class II genes

Q: The initial infective stage of the malarial parasite is the A) sporozoite. B) merozoite. C) schizont. D) plasmodyite.

Q: Malaria is A) the most common cause of death due to infectious disease worldwide. B) prevented or treated with chloroquine. C) controlled by reducing the population of the mosquito vector. D) the most common cause of death due to infectious disease worldwide, although it can be controlled by reducing the population of the mosquito vector and prevented or treated with chloroquine.

Q: Treatment of ALL pathogenic E. coli infections involves supportive therapy and, in some cases, may also include antimicrobial drugs.

Q: Mass-processed ground meat is a particularly common source of infection with EHEC.

Q: Antibiotic therapy is not significantly useful for treating typhoid fever.

Q: It is estimated that less than 4% of all cases of salmonellosis are reported.

Q: To be certain the botulinum toxin is inactivated, the source must be heated for at least 2 minutes at 100C.

Q: With Clostridium perfringens, the enterotoxin is present in the endospores that germinate under anoxic conditions.

Q: Many food infection agents also cause waterborne diseases.

Q: Food poisoning generally results from the ingestion of food containing microbial toxins.

Q: Properly canned foods are sterile.

Q: Acidic foods generally need a higher canning temperature than do nonacidic foods.

Q: For much of the period of microbial growth in food, there is no visible or easily detectable change in food quality.

Q: Ideally, microbes should be eliminated from ALL foods.

Q: Legionellosis, caused by the bacterial respiratory pathogen Legionella pneumophila, has decreased in recent years due to advances in wastewater treatment procedures.

Q: The U.S. Environmental Protection Agency (EPA) regulates the concentration of Escherichia coli in public recreational waters as well as private swimming pools, spas, and hot tubs to minimize waterborne disease outbreaks.

Q: Pathogens that are transmitted via the fecal-oral route are the most common type of pathogens that infect drinking water.

Q: Coliforms can be present in 5% of drinking water samples tested within a month and still be considered safe according to the U.S. Environmental Protection Agency (EPA).

Q: Not all coliforms are pathogenic.

Q: Water is considered to be the third most important common source of infectious diseases.

Q: Typhoid fever has been virtually (although not completely) eliminated from developed countries.

Q: Infection with Legionella pneumophila is usually treated with intravenous erythromycin.

Q: We are technically in the midst of a cholera pandemic.

Q: Cholera can be transmitted by water or food.

Q: Local and state authorities can set standards for recreational water that are above or below the guidelines set by the United States government.

Q: BOTH physical and chemical methods are used to treat and purify water.

Q: Which of the following bacterial pathogens is found in aquatic environments and is commonly present in air conditioning systems? A) Enterobacter aerogenes B) Klebsiella pneumoniae C) Legionella pneumophila D) Vibrio cholerae

Q: What is the medium used in the membrane filter (MF) procedure to differentiate fecal coliforms and Escherichia coli? A) mannitol salt agar B) eosin-methylene blue agar C) triple sugar iron agar D) blood agar

Q: Which of the following is NOT characteristic of a coliform? A) facultatively aerobic B) gram-negative C) rod shaped D) resistant to chlorination

Q: Legionella pneumophila is generally transmitted by A) contaminated food. B) contaminated drinking water. C) contaminated water in coolers, pools, and domestic water systems. D) personto-person contact.

Q: Vibrio cholerae primarily infects the A) stomach. B) small intestine. C) large intestine. D) rectum.

Q: In the United States, individuals become infected with Vibrio cholerae most commonly by A) consuming contaminated shellfish. B) drinking contaminated water. C) eating contaminated vegetables. D) person-to-person contact.

Q: The presence of specific ________ signals that a given water source might be contaminated with pathogens. A) exotoxins B) chemical compounds C) endotoxins D) indicator microorganisms

Q: The MOST common route of transmission of Salmonella typhi worldwide is through A) contaminated food. B) contaminated water. C) direct contact. D) insect vectors.

Q: In the developed countries of the world, MOST intestinal infections are transmitted via A) water. B) person-to-person contact. C) food. D) hospital contamination.

Q: Which U.S. government agency monitors water utility reports? A) Environmental Protection Agency B) Food and Drug Administration C) Water Safety Board D) Natural Resources Conservancy Commission

Q: Coliforms in a water sample indicate ________ contamination. A) fecal B) industrial or chemical C) arthropod D) All of the answers are correct.

Q: The type of Escherichia coli that produces a verotoxin similar to the one produced by Shigella dysenteriae is ________ E. coli. A) enterohemorrhagic B) enterotoxigenic C) enteropathogenic D) enteroimmunogenic

Q: The MOST common source of individual foodborne botulism outbreaks are due to consumption of A) honey. B) dairy products. C) nonacid, home-canned vegetables. D) egg and meat salads.

Q: Which organisms are NOT involved in food fermentations? A) lactic acid bacteria B) sulfuric acid bacteria C) acetic acid bacteria D) propionic acid bacteria

Q: Which items are MOST routinely irradiated in the United States? A) fresh fruits B) fish C) canned foods D) herbs and spices

Q: With the exception of some gram-positive cocci, what concentration of NaCl inhibits nearly all bacterial growth? A) 2.5% B) 5% C) 7.5% D) 10%

Q: When solute is added to food products, the water activity (aw) A) increases. B) decreases. C) remains the same. D) initially increases and then decreases.

Q: What organisms are good competitors for free water present in foods with low aw? A) gram-positive cocci B) fungi C) gram-negative bacilli D) gram-positive bacilli

Q: Enteric bacteria such as Salmonella spp., Shigella spp., and Escherichia spp. most often contaminate and spoil A) meat. B) fruits. C) grains. D) milk and milk products.

Q: To prevent the spread of pathogens that cause listeriosis, raw food and food-handling equipment can be decontaminated with A) antibiotic spray. B) radiation. C) cold storage. D) antibiotic spray, radiation, and cold storage.

Q: Listeriosis is diagnosed from ________ cultures and treated with ________. A) sputum / intravenous antibiotics B) blood or spinal fluid / hydration therapy C) sputum / hydration therapy D) blood or spinal fluid / intravenous antibiotics

Q: Listeria monocytogenes is A) acid-tolerant. B) cold-tolerant. C) salt-tolerant. D) acid-, cold-, and salt-tolerant.

Q: The Campylobacter spp. are A) aerobes. B) anaerobes. C) microaerophiles. D) facultative anaerobes.

Q: ETEC strains produce one of two heat-________ diarrhea-producing ________. A) stable / endotoxins B) labile / endotoxins C) stable / enterotoxins D) labile / enterotoxins

Q: Verotoxin can cause A) hemorrhagic diarrhea. B) liver failure. C) brain damage. D) hemorrhagic diarrhea, liver failure, and brain damage.

Q: Salmonellosis is most frequently caused by A) Salmonella enterica serovar Typhi. B) Salmonella enterica serovar Typhimurium. C) Salmonella enterica serovar Enteriditis. D) Salmonella enterica serovars Typhimurium and Enteriditis.

Q: Clostridium botulinum is a gram- ________ rod that produces an ________. A) negative / endotoxin B) negative / exotoxin C) positive endospore-forming / exotoxin D) positive endospore-forming / endotoxin

Q: Clostridium perfringens food poisoning leads to diarrhea, because the A) toxin causes the shedding of the intestinal lining. B) permeability of the intestinal epithelium is altered by the toxin it produces. C) disease causes such extreme thirst that the patient drinks more water than can be absorbed. D) organism multiplies more rapidly than the immune system can handle.

Q: Severe cases of Staphylococcus aureus food poisoning may require treatment A) with powerful antibiotics. B) for dehydration. C) with cleansing enemas. D) for dehydration, along with powerful antibiotics and cleansing enemas.

Q: Staphylococcus aureus is a common foodborne disease, because it A) grows on common foods. B) is present in some humans that work in food processing. C) produces several heat-stable enterotoxins. D) grows on many foods, is present in some humans that work in food processing, and produces several heat-stable enterotoxins.

Q: The Staphylococcus aureus toxins are A) neurotoxins. B) endotoxins. C) ectotoxins. D) superantigen toxins.

Q: Pickling is a type of food preservation utilizing A) weak acids. B) basic substances. C) lyophilization. D) irradiation.

Q: The principle behind salt or sugar preservation is to A) introduce a mechanical barrier to microbial invasion. B) reduce water activity (aw). C) introduce a microbicide in anticipation of contaminating bacteria or fungi. D) accomplish all of the described functions depending on the food being preserved.

Q: The pH of MOST foods is A) basic. B) neutral or basic. C) acidic. D) neutral or acidic.

Q: Psychrotolerant microorganisms can survive and grow at A) refrigeration temperatures. B) boiling temperatures. C) extreme fluctuations in water availability. D) high salt or sugar concentrations.

Q: The rate of contaminant microbial growth during the exponential phase in food depends on A) temperature. B) the nutrient value of the food. C) water content. D) temperature, nutrient value, and water content.

Q: At what temperature are most household freezers kept? A) 4C B) 0C C) -20C D) -80C

Q: Flour and sugar are classified as ________ foods. A) highly perishable B) semiperishable C) nonperishable D) selectively perishable

Q: The degree of susceptibility a food has to microbial activity is determined by its A) chemical characteristics. B) physical characteristics. C) water content. D) chemical characteristics, physical characteristics, and water content.

Q: The MOST important potential common source of infectious disease is A) industrial waste. B) arthropod reservoirs found near surface water supplies. C) water. D) human and animal wastes.

Q: Why are antibiotics of little value by themselves in the treatment of cholera?

Q: Identify and define the categories of food perishability. Compare the perishability of sugar, milk, and hard cheeses (such as parmesan).

Q: As a visitor to a country in which cholera is an endemic disease, what specific steps would you take to reduce your risk of cholera exposure? Will these precautions also prevent you from contracting other waterborne diseases? If so, which ones? Identify waterborne diseases for which your precautions may not prevent infection.