37 Questions
Which of the following organisms is most likely responsible for a 22-year-old male college student's severe vomiting after consuming old fried rice?
Bacillus cereus
Which of the following organisms is most likely responsible for a 30-year-old lady's muscle paralysis and difficulty in breathing after consuming canned fish with rice?
Clostridium botulinum
Which organism is most likely responsible for an outbreak of food poisoning with severe bloody diarrhea among children after eating dinner at a BBQ farm?
E. coli O157:H7
What is the difference between foodborne intoxication and infection?
Intoxication is caused by consuming food contaminated with toxins, while infection is caused by consuming live bacteria.
Which two foodborne pathogens have caused over 90% of worldwide bacteria-related foodborne illness?
E. coli O157:H7 and Salmonella
In a case of Staphylococcal intoxication, how long does it take after exposure before symptoms are evident?
2-6 hours
In which types of food does Clostridium botulinum grow?
Low-acid foods like vegetables, fish, and meat products
What temperature is required to destroy the spores of Clostridium botulinum?
118°C for 20 minutes
Which type of toxin does Bacillus cereus produce that is heat-stable?
Emetic toxin
What is the lethal dosage of the toxin produced by Clostridium botulinum?
0.1 ng
Which of the following microorganisms is commonly used in food processing?
Lactobacillus acidophilus
What is the main factor influencing the growth of microorganisms in food?
Water activity
Which of the following organisms is likely to cause food spoilage in a refrigerator?
Thermophilic bacteria
What is the temperature range for psychrophilic microorganisms?
0-7°C
Which factor is crucial for microbial growth, with minimal water activity required being 0.95 for most fresh foods?
Relative humidity
At what pH level are bacterial pathogens typically unable to grow?
pH < 4.0
Which phase of the microbial growth curve involves reduced nutrients?
Stationary phase
What is the temperature danger zone for microbial growth?
5 - 60˚C
Which classification is based on the temperature range in which organisms can grow?
Psychrophiles, mesophiles, and thermophiles
Which method is used to inhibit microbial growth in the food industry and has specific temperature ranges for effectiveness?
Pasteurization
What does relative humidity impact in food?
Water activity
Which technique is used to control microbial growth in food items and involves the addition of weak acids?
Pickling
What is the range for the temperature danger zone for microbial growth?
5 - 60˚C
Which method is used to inhibit microbial growth and involves the use of weak acids like vinegar?
Pickling
What is the classification based on the amount of moisture in the air that impacts water activity in food?
Relative humidity
Which phase of the microbial growth curve involves favorable growth conditions?
Log phase
Which type of bacteria causing foodborne illness forms spores?
Listeria monocytogenes
What is the aim of food preservation?
To prevent spoilage and extend shelf life while ensuring safety
What is the D value in thermal destruction kinetics?
The time required to destroy 90% of microorganisms at a specific temperature
Which method of food preservation involves adding acid, salt, or sugar?
Chemical methods
Which bacteria causing foodborne intoxication is associated with heat-stable toxins?
Bacillus cereus
What is the Z value in thermal destruction kinetics?
The temperature change needed to achieve a 90% reduction in the D-value
Which bacteria causing foodborne infection includes Salmonella?
Salmonella
Which virus can cause foodborne illness?
Norovirus
What is the aim of biological methods in food preservation?
To use fermentation
What does UHT stand for in heat treatment methods for food preservation?
Ultra-Heat Treatment
What does F value measure in thermal destruction kinetics?
The time-temperature combination needed to achieve a specific reduction in the number of microorganisms
Study Notes
Foodborne Illness and Food Preservation
- Foodborne illness can be caused by infectious agents (pathogens) such as bacteria, molds, viruses, and parasites, as well as toxins or chemicals.
- There are two main types of foodborne illness: foodborne infection, caused by live pathogenic microorganisms in food, and foodborne intoxication, caused by ingesting toxins formed by microorganisms in the food.
- Pathogenic bacteria causing foodborne infection include Vibrio parahaemolyticus, Vibrio cholerae, Bacillus cereus, and Salmonella, while bacteria causing foodborne intoxication include Staphylococcus aureus, Clostridium botulinum, and Escherichia coli.
- Psychrophilic bacteria include Listeria monocytogenes, while bacteria that can form spores include Bacillus cereus.
- Foodborne illness can also be caused by viruses such as Norovirus and Hepatitis A virus, mold toxins like Ergot and Aflatoxin, and protozoa leading to illnesses like Ciguatera food poisoning.
- Food preservation aims to prevent spoilage, loss of quality, and extend the shelf life of food products while ensuring their safety.
- Principles of food preservation involve the elimination or inactivation of microorganisms, stopping enzyme action, and preventing oxidation.
- Methods of food preservation include physical methods like heating and low temperature, chemical methods such as adding acid, salt, or sugar, and biological methods like fermentation.
- Heat treatment methods for food preservation include pasteurization at 72°C for HTST milk, UHT milk, and sterilization, which completely kills or removes all life forms, including bacteria and other organisms.
- Thermal destruction kinetics measures the efficiency of thermal-killing and involves values like D value, Z value, and F value, which relate to time, temperature, and the death of microorganisms.
- D value is the time required to destroy 90% of microorganisms at a specific temperature, while Z value is the temperature change needed to achieve a 90% reduction in the D-value.
- Understanding foodborne illness and food preservation methods is crucial for ensuring food safety and preventing foodborne illnesses.
Test your knowledge of Vibrio cholerae with this quiz! Learn about the characteristics, types of illness, and reservoir of this curved, rod-shaped, Gram-negative bacterium.
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