Chapter 31 Water and Food as Vehicles of Bacterial Diseases,100% CORRECT

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. 2) 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. 3) Flour and sugar are classified as ________ foods. A) highly perishable B) semiperishable C) nonperishable D) selectively perishable 4) At what temperature are most household freezers kept? A) 4°C B) 0°C C) -20°C D) -80°C 5) 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. 6) 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. 7) The pH of MOST foods is A) basic. B) neutral or basic. C) acidic. D) neutral or acidic. 8) 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. 9) Pickling is a type of food preservation utilizing A) weak acids. B) basic substances. C) lyophilization. D) irradiation. 10) The Staphylococcus aureus toxins are A) neurotoxins. B) endotoxins. C) ectotoxins. D) superantigen toxins. 11) 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. 12) 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. 13) 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. 14) 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 15) 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. 16) Verotoxin can cause A) hemorrhagic diarrhea. B) liver failure. C) brain damage. D) hemorrhagic diarrhea, liver failure, and brain damage. 17) ETEC strains produce one of two heat-________ diarrhea-producing ________. A) stable / endotoxins B) labile / endotoxins C) stable / enterotoxins D) labile / enterotoxins 18) The Campylobacter spp. are A) aerobes. B) anaerobes. C) microaerophiles. D) facultative anaerobes. 19) Listeria monocytogenes is A) acid-tolerant. B) cold-tolerant. C) salt-tolerant. D) acid-, cold-, and salt-tolerant. 20) 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 21) 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. 22) 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. 23) 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 24) 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. 25) 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% 26) Which items are MOST routinely irradiated in the United States? A) fresh fruits B) fish C) canned foods D) herbs and spices 27) Which organisms are NOT involved in food fermentations? A) lactic acid bacteria B) sulfuric acid bacteria C) acetic acid bacteria D) propionic acid bacteria 28) 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. 29) 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 30) Coliforms in a water sample indicate ________ contamination. A) fecal B) industrial or chemical C) arthropod D) All of the answers are correct. 31) 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 32) 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. 33) The MOST common route of transmission of Salmonella typhi worldwide is through A) contaminated food. B) contaminated water. C) direct contact. D) insect vectors. 34) 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 35) 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. 36) Vibrio cholerae primarily infects the A) stomach. B) small intestine. C) large intestine. D) rectum. 37) Legionella pneumophila is generally transmitted by A) contaminated food. B) contaminated drinking water. C) contaminated water in coolers, pools, and domestic water systems. D) person—to-person contact. 38) Which of the following is NOT characteristic of a coliform? A) facultatively aerobic B) gram-negative C) rod shaped D) resistant to chlorination 39) 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 40) 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 True/False Questions 1) BOTH physical and chemical methods are used to treat and purify water. 2) MOST wastewater treatment facilities employ methods designed to detect each pathogenic organism that may be present in a given sample. 3) Local and state authorities can set standards for recreational water that are above or below the guidelines set by the United States government. 4) Cholera can be transmitted by water or food. 5) We are technically in the midst of a cholera pandemic. 6) Infection with Legionella pneumophila is usually treated with intravenous erythromycin. 7) Typhoid fever has been virtually (although not completely) eliminated from developed countries. 8) Water is considered to be the third most important common source of infectious diseases. 9) Not all coliforms are pathogenic. 10) 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). 11) For water to be considered safe to drink, it must be treated with four distinct methods. 12) Pathogens that are transmitted via the fecal-oral route are the most common type of pathogens that infect drinking water. 13) 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. 14) Legionellosis, caused by the bacterial respiratory pathogen Legionella pneumophila, has decreased in recent years due to advances in wastewater treatment procedures. 15) Ideally, microbes should be eliminated from ALL foods. 16) For much of the period of microbial growth in food, there is no visible or easily detectable change in food quality. 17) Acidic foods generally need a higher canning temperature than do nonacidic foods. 18) Properly canned foods are sterile. 19) Food poisoning generally results from the ingestion of food containing microbial toxins. 20) Many food infection agents also cause waterborne diseases. 21) With Clostridium perfringens, the enterotoxin is present in the endospores that germinate under anoxic conditions. 22) To be certain the botulinum toxin is inactivated, the source must be heated for at least 2 minutes at 100°C. 23) It is estimated that less than 4% of all cases of salmonellosis are reported. 24) Antibiotic therapy is not significantly useful for treating typhoid fever. 25) Mass-processed ground meat is a particularly common source of infection with EHEC. 26) Treatment of ALL pathogenic E. coli infections involves supportive therapy and, in some cases, may also include antimicrobial drugs. 27) Nearly ALL cases of acute listeriosis require hospitalization. 28) Gram-negative bacteria are responsible for causing MOST foodborne diseases. 29) Campylobacter infections are the MOST common foodborne infections in the United States. 30) Escherichia coli is found naturally in the intestines of birds, humans, and animals. Essay Questions 1) Explain why coliforms are used to detect water contamination rather than directly quantifying individual pathogens such as Vibrio cholerae or Salmonella spp. 2) Compare and contrast the most probable number (MPN) procedure and the membrane filter (MF) procedure. 3) There were numerous cases throughout the United States of patients having bloody diarrhea all within a week of each other, many of which were hospitalized with severe cases. Although the people spanned from California to New York, they all had attended a high school graduation party. Epidemiologists determined the common food factor was cheese curds homemade by a farmer. The home where the cheese curds were made was searched, and the cheese curds and milk used to produce them were taken to the local government lab. Among other microbes, Campylobacter jejuni was isolated from many of the cheese curds as well as the farmer's bulk tank milk. What should be done for those infected? What can be done to prevent this from happening again? 4) What makes Listeria monocytogenes an especially difficult-to-prevent foodborne pathogen? Once in the human body, how does it evade the immune system? 5) Why are enteric bacteria such as Escherichia coli common meat contaminants? 6) How does Clostridium perfringens cause food poisoning? How is this process related to the metabolism and special structures of C. perfringens? 7) Why is Staphylococcus aureus often described as an international picnic pest? 8) What is the difference between food poisoning and food infection? Are antibiotics useful in either of them? 9) 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. 10) Identify and define the categories of food perishability. Compare the perishability of sugar, milk, and hard cheeses (such as parmesan). 11) Why are antibiotics of little value by themselves in the treatment of cholera?