Food Safety and Pathogens Quiz
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Questions and Answers

What types of antibiotics is the agent sensitive to?

The agent is sensitive to streptomycin, tetracycline, chloramphenicol, kanamycin, and novobiocin.

At what temperature and duration can the agent be killed by heat?

The agent can be killed by heat at 55ËšC for 15 minutes.

What hygienic measures can help prevent infections caused by the agent?

Properly heated municipal water provision, boiling or chemically treating water, and proper sewage disposal.

Why should seafood not be eaten raw regarding food safety?

<p>Raw seafood may contain pathogens that are not killed, increasing the risk of foodborne infections.</p> Signup and view all the answers

How do foodborne viruses primarily transmit infections?

<p>Foodborne viruses are primarily transmitted via the oral-fecal route.</p> Signup and view all the answers

What is the size range of foodborne viruses?

<p>Foodborne viruses typically range from 15 to 400 nm in diameter.</p> Signup and view all the answers

Where do viruses replicate, and why is it significant?

<p>Viruses can only replicate in living cells, which is significant for understanding infection mechanisms.</p> Signup and view all the answers

What type of contamination leads to infectious hepatitis?

<p>Infectious hepatitis is caused by fecal contamination of water or food.</p> Signup and view all the answers

What are the two major types of diseases caused by Salmonella in humans?

<p>Gastroenteritis and typhoid fever.</p> Signup and view all the answers

Describe the general symptoms of Salmonella infection.

<p>Symptoms include abdominal cramps, diarrhea, nausea, vomiting, chills, fever, and prostration.</p> Signup and view all the answers

What is the optimum growth temperature range for Salmonella?

<p>The optimum growth temperature is between 35 and 37°C.</p> Signup and view all the answers

Where are Salmonella naturally found?

<p>They are natural inhabitants of the gastrointestinal tracts of animals and can also exist in soil, water, and sewage.</p> Signup and view all the answers

What toxins are produced by Clostridium perfringens, and what are their effects?

<p>C.perfringens produces enterotoxin and β-toxin, which cause gastrointestinal illnesses.</p> Signup and view all the answers

What types of foods are typically associated with Salmonella infections?

<p>Foods of animal origin such as beef, chicken, turkey, pork, eggs, and milk products.</p> Signup and view all the answers

How does Clostridium perfringens survive in food?

<p>It has heat-resistant spores and vegetative cells that survive in incompletely cooked foods.</p> Signup and view all the answers

What environmental conditions inhibit the multiplication of Salmonella?

<p>Salmonella does not multiply at aw levels of 0.94 or at low pH of 4.5 or below.</p> Signup and view all the answers

What are the main characteristics of Yersinia enterocolitica?

<p>Yersinia enterocolitica are gram-negative short rods, nonsporeforming, motile below 37°C, and facultative anaerobic.</p> Signup and view all the answers

Describe the habitat of Yersinia enterocolitica.

<p>Yersinia enterocolitica is a normal inhabitant of the intestines of food animals, birds, pets, wild animals, and humans.</p> Signup and view all the answers

What symptoms are associated with yersiniosis and how long do they last?

<p>Symptoms include severe abdominal pain, diarrhea, nausea, vomiting, and fever, lasting for 2 to 3 days.</p> Signup and view all the answers

What food items are commonly associated with Yersinia enterocolitica infections?

<p>Commonly associated food items include raw milk, processed dairy products, raw and improperly cooked meats, and fresh vegetables.</p> Signup and view all the answers

How are Vibrio spp. primarily transmitted to humans?

<p>Vibrio spp. are primarily transmitted through the consumption of raw or undercooked shellfish or exposure of wounds to warm seawater.</p> Signup and view all the answers

What is the significance of the Kanagawa phenomenon in Vibrio infections?

<p>The Kanagawa phenomenon is associated with pathogenicity in Kanagawa-positive vibrios, which can cause gastroenteritis.</p> Signup and view all the answers

What are the symptoms of gastroenteritis caused by Kanagawa-positive Vibrio strains?

<p>Symptoms include severe abdominal pain, diarrhea, nausea, vomiting, mild fever, and headache.</p> Signup and view all the answers

Where can Kanagawa-positive Vibrio strains be isolated from?

<p>They can be isolated from sediment, plankton, sea fish, crustaceans, and shellfish in coastal and estuarine environments.</p> Signup and view all the answers

What is foodborne disease and how does it differ from food intoxication?

<p>Foodborne disease is an illness resulting from contaminated food, while food intoxication specifically refers to illnesses caused by bacterial toxins in food.</p> Signup and view all the answers

Identify two ways pathogens can be transmitted through food.

<p>Pathogens can be transmitted through contaminated food and by insects that carry pathogens to food.</p> Signup and view all the answers

What role do insects play in the transmission of foodborne pathogens?

<p>Insects, such as house flies, can spread pathogens like Salmonella and E.coli by transferring microbes from their body to food.</p> Signup and view all the answers

Describe how contaminated wastewater can lead to the transmission of pathogens.

<p>Contaminated wastewater can flow into drinking water sources, containing microbes from human or animal feces, which can cause infections.</p> Signup and view all the answers

What is the first stage of transmission for a pathogen to a new host?

<p>The first stage of transmission is the escape of the infectious agent from its host or reservoir.</p> Signup and view all the answers

Name one type of nonbacterial agent of foodborne disease and provide an example.

<p>One type of nonbacterial agent is parasites; an example is Giardia.</p> Signup and view all the answers

What are fomites and how can they contribute to foodborne disease transmission?

<p>Fomites are non-living objects that can harbor pathogens, such as rusted barbed wire, which can cause infections when they contact wounds.</p> Signup and view all the answers

List two bacterial agents commonly associated with foodborne disease.

<p>Two common bacterial agents are Salmonella and Escherichia coli.</p> Signup and view all the answers

What is the primary etiologic agent of Toxoplasmosis?

<p>The primary etiologic agent of Toxoplasmosis is the protozoan Toxoplasma gondii.</p> Signup and view all the answers

How are sporulated and unsporulated oocysts related to Toxoplasmosis?

<p>Sporulated oocysts are shed in cat feces and can contaminate food, while unsporulated oocysts are not yet infectious.</p> Signup and view all the answers

Identify the definitive hosts for Toxoplasma gondii.

<p>The definitive hosts for Toxoplasma gondii are felids, including domestic cats.</p> Signup and view all the answers

What is Sarcocystosis and its etiologic agent?

<p>Sarcocystosis refers to coccidian parasites that inhabit muscle tissue, with the etiologic agent being Sarcocystis species.</p> Signup and view all the answers

What are the implications of congenital Toxoplasmosis infections?

<p>Congenital Toxoplasmosis infections can cause parasitemia in the mother and potentially infect the fetus.</p> Signup and view all the answers

What is the causative agent of human trichinellosis?

<p>The causative agent of human trichinellosis is the parasite Trichinella spiralis.</p> Signup and view all the answers

Describe the lifecycle stage of Trichinella spiralis post-infection.

<p>Post-infection, fertilized female trichinae burrow into the intestinal wall and release larvae into the bloodstream.</p> Signup and view all the answers

How do well-adapted parasites differ in relation to their hosts?

<p>Well-adapted parasites typically do not kill their hosts, ensuring their own survival and continued reproduction.</p> Signup and view all the answers

What are the two main types of infections caused by tapeworms, and what distinguishes them?

<p>Taeniasis is caused by adult tapeworms in the intestines of humans, while cysticercosis is caused by larval stages that can infect various tissues within the body.</p> Signup and view all the answers

Identify the two species of tapeworms mentioned and their corresponding animal hosts.

<p>Taenia saginata is known as the beef tapeworm and is associated with cattle, while Taenia solium is the pork tapeworm linked to pigs.</p> Signup and view all the answers

What is the role of the scolex in tapeworms, and what specific feature does Taenia solium have?

<p>The scolex is the head of the tapeworm that allows it to attach to the intestinal wall, and Taenia solium has hooks on its scolex for better attachment.</p> Signup and view all the answers

Describe the significance of Capillaria philipiensis and its primary host.

<p>Capillaria philipiensis is a nematode first reported in the Philippines that primarily resides in the small intestines, and its definitive host is humans.</p> Signup and view all the answers

Explain the mode of transmission for Anisakis simplex and its definitive hosts.

<p>Anisakis simplex, a larval stage nematode, primarily transmits through the consumption of contaminated fish or seafood, with whales and dolphins as definitive hosts.</p> Signup and view all the answers

What are mycotoxins, and which fungi produce aflatoxins?

<p>Mycotoxins are toxic secondary metabolites produced by fungi, specifically aflatoxins produced by Aspergillus flavus and Aspergillus parasiticus.</p> Signup and view all the answers

Identify a mycotoxin that exhibits fungistatic activity and its effects on plants.

<p>Patulin is a mycotoxin with strong fungistatic activity, toxic to seeds and seedlings of various higher plants like corn and wheat.</p> Signup and view all the answers

What is Ochratoxin A, and which organism is it isolated from?

<p>Ochratoxin A is a toxic metabolite isolated from Aspergillus ochraceus that is harmful to various animals like ducklings and rats.</p> Signup and view all the answers

Flashcards

Foodborne Disease

Illness resulting from consuming contaminated food, containing pathogenic bacteria, viruses, parasites, or chemical/natural toxins.

Food Intoxication

Food-borne illness caused by the ingestion of bacterial toxins pre-formed in food.

Food Infection

Food-borne illness caused by the entry of bacteria into the body through contaminated food.

Person-to-Person Transmission

The spread of pathogens from person to person through direct contact, like coughing or sneezing.

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Transmission by Food

The spread of pathogens through contaminated food, like Salmonella from raw chicken.

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Transmission by Contaminated Wastewater

The spread of pathogens through contaminated wastewater, like drinking water contaminated with fecal matter.

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Transmission by Insects

The spread of pathogens through insects, like flies carrying Salmonella and E. coli O157.

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Transmission by Fomites

The spread of pathogens through non-living objects like barbed wire, leading to tetanus from punctured wounds.

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Salmonella

A rod-shaped, Gram-negative bacterium that can cause gastroenteritis and typhoid fever.

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Salmonellosis

An infection caused by Salmonella bacteria, usually through contaminated food or water.

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Gastroenteritis

A type of salmonellosis that affects the intestines, causing symptoms like diarrhea, nausea, and vomiting.

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Typhoid Fever

A more severe form of salmonellosis that can lead to fever, headache, and abdominal pain.

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Mesophilic

A category of bacteria that thrive in moderate temperatures.

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Facultative Anaerobic

The ability of bacteria to survive in the absence of oxygen.

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Motile

The ability of bacteria to move independently using flagella.

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Clostridium perfringens Food Poisoning

A type of food poisoning caused by the bacterium Clostridium perfringens.

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What are the characteristics of the bacterium (ex: sensitivity to antibiotics)?

A bacterium that is sensitive to antibiotics like streptomycin, tetracycline, chloramphenicol, kanamycin, and novobiocin, and is killed by heat at 55ËšC for 15 minutes.

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How long can the bacterium survive in feces?

This bacterium can survive in feces for a few weeks at 1ËšC, but is killed within a day or two at room temperature.

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How can we prevent the spread of the bacteria?

Proper hygiene is essential, including access to clean water, sewage disposal, and avoiding raw seafood.

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What causes a foodborne viral infection?

Foodborne infections occur when food contaminated with viruses is ingested.

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Describe the characteristics of foodborne viruses.

Viruses are small acellular microorganisms, typically 15 to 400 nm in diameter, containing only one type of nucleic acid.

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What does it mean for a virus to be an "obligate intracellular parasite"?

Viruses are obligate intracellular parasites, meaning they can only replicate inside living cells.

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How are foodborne viruses transmitted?

Foodborne viruses are transmitted through the oral-fecal route, often by contaminated water, food, or contact with infected individuals or animals.

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What is infectious hepatitis?

Infectious hepatitis is a liver infection caused by a virus that enters the body through the oral route, often due to contaminated water or food.

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What is a parasite?

A parasitic organism obtaining nourishment from a living host, generally without killing it.

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What is Toxoplasma gondii?

A single-celled parasite that lives inside the cells of its host. It's responsible for toxoplasmosis, a disease typically spread through contaminated food.

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What are the stages of Toxoplasma gondii's life cycle?

The life cycle of Toxoplasma gondii includes two stages: sporulated and unsporulated. Sporulated oocysts are shed in cat feces and are infectious. Unsporulated oocysts are not infectious.

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What is sarcocystosis?

An illness caused by the parasite Sarcocystis. It affects muscle tissue and can be found in various mammals, birds, and reptiles.

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What is Trichinella spiralis?

This roundworm, also known as Trichinella spiralis, primarily infects humans through undercooked pork.

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How does Trichinella spiralis infect a host?

The process of Trichinella spiralis infection: After ingestion, female worms release larva in the gut. These larva travel to muscles, encapsulate themselves, and cause trichinellosis.

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What is trichinellosis?

Infection by a parasite belonging to the Nematoda phylum, typically caused by Trichinella spiralis. This infection is usually acquired through eating undercooked meat, especially pork.

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Yersinia enterocolitica

A type of bacteria known for causing yersiniosis, a foodborne illness. They are small, rod-shaped, and can survive a wide range of temperatures.

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Yersiniosis

A condition caused by the bacteria Yersinia enterocolitica, often resulting from consuming contaminated food. Symptoms include severe abdominal pain, diarrhea, nausea, vomiting, and sometimes fever.

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Transmission of Vibrio infections

One of the main ways to get sick from Vibrio spp. bacteria, usually by consuming raw shellfish or exposing an open wound to warm seawater.

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Vibrio spp.

A type of bacteria known for causing foodborne illness, often found in seafood. They are curved, rod-shaped and thrive in marine environments.

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Kanagawa Phenomenon

A type of bacterial toxin associated with certain Vibrio spp., known as Kanagawa-positive vibrios. These bacteria can cause gastroenteritis.

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Kanagawa-positive vibrios

Certain Vibrio spp. that contain the specific toxin known as the Kanagawa phenomenon and are known to cause gastroenteritis, which can result from consuming contaminated food.

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Cysticercosis

A type of parasitic infection caused by the larval stage of the tapeworm Taenia solium.

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Taeniasis

A type of parasitic infection caused by the adult stage of the tapeworm Taenia saginata, typically acquired from eating undercooked beef.

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Scolex

The head of a tapeworm, containing hooks and suckers that allow it to attach to the intestinal wall.

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Capillaria philippinensis

A type of nematode parasite that infects the small intestines of humans, primarily found in Southeast Asia. It is characterized by its small size and stichocytes, which are cells that surround the esophagus.

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Gnathostoma spp.

A genus of nematode parasites, commonly known as the "spiny-headed worms."

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Anisakis simplex

A type of nematode that infects marine mammals. The larval stages are found in fish and can cause anisakiasis in humans.

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Aflatoxin

A type of fungal toxin produced by Aspergillus flavus and A. parasiticus.

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Ochratoxin

A toxic metabolite produced by Aspergillus ochraceus, a type of fungus.

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Study Notes

Food Microbiology

  • Foodborne disease is any illness resulting from contaminated food, pathogenic bacteria, viruses, parasites, or chemical or natural toxins
  • Bacterial agents of foodborne disease include:
    • Staphylococcus
    • Clostridium
    • Listeria
    • Salmonella
    • Shigella
    • Escherichia coli
    • Vibrio, Yersinia and Campylobacter

Outline of Foodborne Disease

  • Definition of terms

  • Transmission of pathogens

    • Person to person contact (Measles, mumps, tuberculosis)
    • By food (chicken skin contaminated with Salmonella)
    • By contaminated wastewater (drinking water contaminated by human or animal feces)
    • By insects (House flies spreading Salmonella and E. coli O157)
    • By fomites (non-living objects like barbed wire causing tetanus)

  • Host invasion

  • Pathogenesis

  • Bacterial agents of foodborne disease

    • Staphylococcal intoxication (staphylococcal enterotoxicosis, enterotoxin produced by Staphylococcus aureus)
    • Botulism (neurotoxin produced by Clostridium botulinum)
    • Salmonellosis (endotoxin of Salmonella spp.)
    • Clostridium perfringens illness (enterotoxin released during sporulation of Clostridium perfringens type A)
    • Bacillus cereus gastroenteritis (exoenterotoxin released during lysis of Bacillus cereus)
    • Enteropathogenic Escherichia coli infection (several stereotypes of E. coli, some invasive and some enterotoxigenic)
    • Yersiniosis
    • Shigellosis
    • Vibrio parahaemolyticus

  • Nonbacterial agents of foodborne disease

    • Parasites
    • Viruses
    • Molds

Foodborne Disease: Bacterial Intoxication

  • Staphylococcal Intoxication

    • Caused by ingestion of enterotoxins of Staphylococcus aureus
    • Termed as enterotoxin, causing gastroenteritis/intestinal inflammation
    • Staphylococcus aureus characteristics: Gram-positive cocci, occur in bunches, nonmotile, noncapsular, nonsporulating
    • Facultatively anaerobic
    • Preferred conditions/growth of Staphylococcus aureus:
      • Ferments carbohydrates
      • Causes proteolysis by extracellular proteolytic enzymes
      • Temperature range of 7 to 48°C, optimally around 20-37°C
      • Water activity (Aw): 0.86
      • pH: 4.8
      • High salt and sugar (15% concentration); presence of NO2
    • Habitat: naturally present in the nose, throat, skin, and hair. Can be present in infections like cuts and facial acne
    • Toxin production: produce 7 distinct enterotoxins
    • Disease/symptoms of intoxication: Gastroenteritis (2-4 hours after consumption, lasts for 1-2 days)
    • Food association: Protein-rich foods, temperature-abused foods, foods handled extensively (ham, corned beef, salami, bacon, barbecued meat, salads, baking products)

  • Botulism

    • Results from consumption of food containing the potent toxin botulin of Clostridium botulinum
    • Botulin is a neurotoxin creating neurological symptoms
    • Clostridium botulinum characteristics
      • Gram-positive rods (single cell or small chains)
      • Motile
      • Obligate anaerobes
      • Single terminal spores that are heat resistant (killed at 115°C)
    • Growth requirements/conditions: sensitive to low pH, low Aw, and moderately high salt; strains can be proteolytic or nonproteolytic
    • Habitat: soil, sewage, mud, sediments; intestinal contents of animals and fishes

  • Other bacterial intoxication details (list of diseases and necessary data are in the provided text)

Foodborne Disease: Bacterial Infection

  • Salmonellosis

    • Cause of disease in humans, animals, and birds
    • Two major types of diseases: gastroenteritis and typhoid fever
    • Caused by eating food contaminated with Salmonella
    • Salmonella details/characteristics (list of necessary data are in the provided text)
    • Disease/symptoms of Salmonella: Abdominal cramps, diarrhea, nausea, vomiting, chills, fever and prostration (symptoms appear generally at 24-36 hours, and last for 2-3 days)
    • Food association: Foods of animal origin (beef, chicken, turkey, pork, eggs, milk and products made from them)

  • Clostridium perfringens illness

    • Cause of food poisoning
    • Bacterial details (list of necessary data are in the provided text)
    • Disease/symptoms of Clostridium perfringens illness:
    • Food association: herbs, spices, processed foods (especially those that are incompletely cooked)

  • Bacillus cereus gastroenteritis

    • Bacterial details (list of necessary data are in the provided text)
    • Disease/symptoms details (list of necessary data are in the provided text)
    • Food association: Dried herbs and spices, meat products, soups, vegetables, and sauces

  • Escherichia coli infection

    • Bacterial characteristics, Pathogenic types of Escherichia coli (list of necessary data are in the provided text)
    • Disease/symptoms details (list of necessary data are in the provided text)

  • Shigellosis

    • Bacterial characteristics, Pathogenic types of Shigella (list of necessary data are in the provided text)
    • Disease/symptoms details ( list of necessary data are in the provided text)

  • Yersiniosis

    • Bacterial characteristics (list of necessary data are in the provided text)
    • Disease/symptoms details (list of necessary data are in the provided text)

  • Vibrio parahaemolyticus

    • History
    • Characteristics of Vibrio parahaemolyticus (list of necessary data are in the provided text)
    • Disease/symptoms
    • Natural habitat
    • Food association
    • Prevention & control methods

  • Vibrio cholerae

    • History
    • Symptoms
    • Characteristics of Vibrio cholerae, and methods for prevention and control

  • Viral Infections 

    • food borne infection caused by ingestion of food containing viruses (survive in gut and attack intestinal flora / bacteriophages / animal viruses).
    • FB Virus Transmission (oral-fecal route)
    • Infectious hepatitis & Poliomyelitis
    • Other viral infections details (list of necessary data are in the provided text)

  • Parasite Infections

    • Toxoplasmosis
      • Caused by the protozoan Toxoplasma gondii
      • Definitive hosts: felids
      • Intermediate hosts: Various warm-blooded animals
      • Infection details
    • Sarcocystosis
      • Caused by coccidian parasites
      • Involves sarcocysts in striated muscles of different animals
      • Infection details
    • Trichinosis
      • Caused by the parasite worm of the Phylum Nematoda belonging to the genus Trichinella
      • Infection involves Trichinella spiralis
      • Infection details
    • Taeniasis/cysticercosis
      • Caused by larval and adult tapeworms
      • Infection details / characteristics of Taenia saginata & T solium
    • Other parasite infections details (list of necessary data are in the provided text)

  • Mold Infections

    • Mycotoxins are fungal metabolites
    • Aflatoxin - produced by Aspergillus flavus and A. parasiticus
    • Patulin
    • exhibits strong fungistatic activity and toxic to seeds and seedlings (sugar beet, corn, wheat)
    • Ochratoxin - toxic metabolite isolated from Aspergillus ochraceus
    • Luteoskyrin
      • produced by Penicillium islandicum

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Test your knowledge on foodborne diseases, their transmission, and prevention methods. This quiz covers key pathogens like Salmonella and Clostridium perfringens, focusing on their characteristics and the risks associated with food safety. Enhance your understanding of how to maintain hygiene and prevent infections related to foodborne viruses.

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