MVPi 001 - Food microbiology Flashcards
Give few example of gram-negative rod
E. Coli, pneumonia, salmonella
Give few examples of endospore former
Bacillus & claustridium species are known to form endospore
Give few examples of food viruses
Food viruses examples include norovirus, hepatitis A and e and rotavirus
Give few examples of myotoxin producer
Penicillium & fusarium
Give some example of differential staining
Gram staining, acid fast staining, endospore staining.
example of proteolytic microorganism.
Archaea certain type of algae,
Give some examples of rapid method of microbial enumeration
Direct cell count, in direct cell count, viable cell count and total cell count
Give some examples of selective culture media
Mcconkey agar, eosin methylene blue (EMB)
Give an example of cocai in bunches
Staphylococcus aureus is an example of cocci that grow in clusters resembling bunches
Define coliform
Coliforms are a group of bacteria that are commonly found in the intestines of humans and animals. Their presence in water or food can indicate that the water or food has been contaminated with fecal matter.
Define food safety
Food safety is the practice of preventing foodborne illness. This involves handling, preparing, and storing food in a way that prevents contamination with harmful bacteria, viruses, or parasites.
Define probiotic
Probiotics are live bacteria that are believed to have health benefits. They are found in yogurt, kefir, and other fermented foods. Probiotics are thought to help improve gut health by crowding out harmful bacteria.
Define food contamination
Food contamination is the presence of harmful substances in food. These substances can be bacteria, viruses, parasites, or chemicals. Food contamination can occur at any point during the food production process, from farm to fork.
Define fermentation
Fermentation is a process in which microorganisms, such as bacteria or yeast, break down carbohydrates into alcohol or lactic acid. Fermentation is used to produce a variety of foods and beverages, including yogurt, cheese, beer, and wine.
What’s the difference between mold and yeast?
- Cell structure: Mold is multicellular, while yeast is unicellular.
- Appearance: Mold forms visible filaments or fuzz, while yeast appears as single cells or small colonies.
- Reproduction: Mold reproduces with spores, while yeast reproduces by budding.
What’s the difference between foot infection versus food? Intoxication?
Infection is caused by live pathogens in food that multiply in your body. Intoxication is caused by toxins produced by bacteria in food, not necessarily the bacteria itself.
Difference between catalase test vs oxidase test
Catalase test: Detects the presence of the enzyme catalase, which breaks down hydrogen peroxide into water and oxygen. A positive test indicates the presence of catalase-producing bacteria. Oxidase test: Detects the presence of the enzyme cytochrome c oxidase, which is involved in the electron transport chain. A positive test indicates the presence of oxidase-producing bacteria
Difference betweenAspergillus vs Penicillium
Aspergillus: Grows rapidly, producing airborne spores. Can cause respiratory problems and allergic reactions. Some species produce toxins that can be harmful or even fatal. . Penicillium: Grows slower than Aspergillus and produces fewer spores. Some species are used to produce penicillin, an antibiotic.
Difference between haleophile versus osmophile
Halophiles: Thrive in environments with high salt concentrations, such as saltwater or soy sauce. Osmophiles: Can tolerate or even require high sugar or salt concentrations for growth.
Spoilage and common physical and chemical changes associated with it
Spoilage is the process by which food becomes unfit for consumption. due to factors like microbial growth (bacteria, mold), enzymatic breakdown, oxidation, or physical damage.
Physical: Slime production, discoloration, leakage of fluids, textural changes (softening or hardening).
Chemical: Off-odors (due to volatile compounds produced by microbes), rancidity (fats breaking down), discoloration (oxidation or enzymatic browning).
Explain the principle of Elisa
ELISA detects the presence of specific molecules (antigens or antibodies) through an antigen-antibody reaction. It relies on colorimetric change to indicate the presence of the target molecule.
Explain PCR and it’s principle
PCR amplifies a specific DNA sequence billions of times, allowing detection of even minute amounts of DNA. It doesn’t rely on antibodies and is often used for identifying pathogens.
what is biosensor
A biosensor is a device that combines biological elements with a physical or chemical detector to detect the presence of a specific substance. It essentially translates a biological response into a measurable electrical signal. Biosensors have various applications in medical diagnostics, environmental monitoring, and food safety.
Additional information
Biosensors are proving to be valuable tools in ensuring food safety. They offer a rapid, sensitive, and specific method for detecting a wide range of contaminants and hazards in food products. Here are some of their applications:
* Detection of foodborne pathogens: Biosensors can identify harmful bacteria like E. coli and Salmonella quickly and accurately. This helps prevent outbreaks of foodborne illness.
* Monitoring toxins and allergens: Biosensors can detect mycotoxins produced by molds and fungi, as well as allergens such as peanuts and gluten. This helps ensure the safety of food for people with allergies.
* Analysis of food quality: Biosensors can be used to measure the freshness of food, detect spoilage, and determine the presence of pesticides or antibiotics.
What is MPN test?
MPN (Most Probable Number) is a technique to estimate bacteria in a liquid sample, especially when there are too few to count directly. It involves diluting the sample, placing it in growth medium, and observing growth patterns to estimate the original bacterial concentration.
Oriental fermented food
variety of traditional foods from East and Southeast Asia that utilize fermentation processes to enhance flavor, texture, and shelf life. Some examples include kimchi (Korea), miso (Japan), and tempeh (Indonesia).
What are prebiotics?
Prebiotics are a type of fiber that act as food for the beneficial bacteria in your gut. These fibers can’t be digested by your body, but they reach your intestines where they’re broken down by gut bacteria. This process helps the bacteria grow and thrive, leading to several health benefits.
What is salmonellosis?
Salmonellosis is an infection caused by bacteria called Salmonella. It typically occurs after consuming contaminated food or water, leading to symptoms like diarrhea, abdominal cramps, fever, and sometimes vomiting. While it’s usually not life-threatening, severe cases may require medical attention.
What is tempeh?
Tempeh is a fermented soybean product from Indonesia, often used as a meat substitute due to its high protein content and firm texture.
What is food microbiology
Food microbiology is the study of microorganisms in food, focusing on safety, quality, and preservation.
What a viruses
Viruses are tiny infectious agents that rely on host cells to replicate, causing diseases in a wide range of organisms.
What are chemical preservativesy
Chemical preservatives are substances added to food and other products to prevent spoilage, degradation, or contamination by microbial growth, oxidation, or other chemical reactions. They help extend shelf life, maintain quality, and ensure product safety. Examples include antioxidants like BHA and BHT, antimicrobials like benzoates and sorbates, and chelating agents like EDTA.
Explain is multiple tube test for water?
The multiple tube test for water is a method used to detect coliform bacteria by inoculating multiple tubes of water samples into a lactose-containing medium, then observing gas production to determine bacterial presence.
_______ are classified as prokaryotic
Bacteria and archaea
Food may go sore when bacteria produces __________?
acids
Foods containing live cells of bacterias are ____________?
Probiotic
The spoilage of honey sugar syrup and jam is generally caused by ________
microbial growth, primarily bacteria, yeast, and molds.
The minimum water activity value of _________ is required by most spoilage molds
0.80
Deliberate contamination of food is called
Food Adulteration
A thick walled spore that developed within cell is called
Endospore
The bacteria which are stained purple in gram-negative are _______ bacteria
Gram-negative bacteria
Killing of microorganism by using flame is called
Sterilization
Use of alcohol is________ method of sterilization
Chemical sterilization
Extrinsic factors for food spoilage
Extrinsic factors for food spoilage include temperature, humidity, atmosphere (presence of gases like oxygen), and external contaminants (such as microorganisms from the environment).
Various types of foodborne diseases
salmonellosis, E. coli infection, listeriosis, norovirus infection, campylobacteriosis, hepatitis A, and botulism.
What is dye reduction test?
The dye reduction test is a microbiological method used to detect the presence of microorganisms, particularly bacteria, in food or other samples. It involves adding a dye to the sample and observing if the dye is reduced (loses color) due to the metabolic activity of living microorganisms.(Milk)
What are mold?
Molds are fungi that grow in multicellular filaments called hyphae and reproduce by forming spores. They cause food spoilage and can be allergens and pathogens.
What is industrial microbiology?
Industrial microbiology is the use of microorganisms in industries to make products or perform tasks, like fermenting foods or producing drugs.
What is complex media?
Complex media is a type of growth medium used in microbiology that contains nutrients from natural sources such as yeast extract, meat extract, or peptone, making it rich in various nutrients needed for microbial growth.
What are Thermoduric microorganism?
Thermoduric microorganisms are microorganisms capable of surviving exposure to high temperatures. They can withstand pasteurization processes commonly used in food and beverage production, which typically involve heating to temperatures between 60°C and 100°C for a short period. Examples include certain bacteria and spores that are resistant to heat.
Explain food contamination
Food contamination occurs when harmful substances or microorganisms are introduced into food, making it unfit for consumption. Contamination can happen at any stage of food production, processing, handling, or preparation. It can be caused by biological agents like bacteria, viruses, or parasites, as well as chemical or physical contaminants. Contaminated food can lead to foodborne illnesses or other health problems when consumed.
Types of food fermentations
- Lactic acid fermentation: Lactose to lactic acid in yogurt production
- Alcoholic fermentation: Grape sugars to ethanol in wine fermentation
- Acetic acid fermentation: Ethanol to acetic acid in vinegar production
- Ethanol fermentation: Sugars to ethanol in biofuel production
- Malolactic fermentation: Malic acid to lactic acid in winemaking
- Propionic acid fermentation: Lactic acid to propionic acid in Swiss cheese production
- Butyric acid fermentation: Lactic acid to butyric acid in fermentation of certain cheeses
________ require high level of salt to grow
Halophiles
To keep microbe out is called
Aseptic
_______ are multicellular, filamentous microorganisms
Moulds