MVPi 001 - Food microbiology Flashcards
1
Q
Give few example of gram-negative rod
A
E. Coli, pneumonia, salmonella
2
Q
Give few examples of endospore former
A
Bacillus & claustridium species are known to form endospore
3
Q
Give few examples of food viruses
A
Food viruses examples include norovirus, hepatitis A and e and rotavirus
4
Q
Give few examples of myotoxin producer
A
Penicillium & fusarium
5
Q
Give some example of differential staining
A
Gram staining, acid fast staining, endospore staining.
6
Q
example of proteolytic microorganism.
A
Archaea certain type of algae,
7
Q
Give some examples of rapid method of microbial enumeration
A
Direct cell count, in direct cell count, viable cell count and total cell count
8
Q
Give some examples of selective culture media
A
Mcconkey agar, eosin methylene blue (EMB)
9
Q
Give an example of cocai in bunches
A
Staphylococcus aureus is an example of cocci that grow in clusters resembling bunches
10
Q
Define coliform
A
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.
11
Q
Define food safety
A
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.
12
Q
Define probiotic
A
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.
13
Q
Define food contamination
A
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.
14
Q
Define fermentation
A
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.
15
Q
What’s the difference between mold and yeast?
A
- 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.
16
Q
What’s the difference between foot infection versus food? Intoxication?
A
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.
17
Q
Difference between catalase test vs oxidase test
A
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
18
Q
Difference betweenAspergillus vs Penicillium
A
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.
19
Q
Difference between haleophile versus osmophile
A
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.
20
Q
Spoilage and common physical and chemical changes associated with it
A
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).
21
Q
Explain the principle of Elisa
A
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.
22
Q
Explain PCR and it’s principle
A
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.
23
Q
what is biosensor
A
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.
24
Q
What is MPN test?
A
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.
25
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).
26
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.
27
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.
28
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.
29
What is food microbiology
Food microbiology is the study of microorganisms in food, focusing on safety, quality, and preservation.
30
What a viruses
Viruses are tiny infectious agents that rely on host cells to replicate, causing diseases in a wide range of organisms.
31
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.
32
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.
33
_______ are classified as prokaryotic
Bacteria and archaea
34
Food may go sore when bacteria produces __________?
acids
35
Foods containing live cells of bacterias are ____________?
Probiotic
36
The spoilage of honey sugar syrup and jam is generally caused by ________
microbial growth, primarily bacteria, yeast, and molds.
37
The minimum water activity value of _________ is required by most spoilage molds
0.80
38
Deliberate contamination of food is called
Food Adulteration
39
A thick walled spore that developed within cell is called
Endospore
40
The bacteria which are stained purple in gram-negative are _______ bacteria
Gram-negative bacteria
41
Killing of microorganism by using flame is called
Sterilization
42
Use of alcohol is________ method of sterilization
Chemical sterilization
43
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).
44
Various types of foodborne diseases
salmonellosis, E. coli infection, listeriosis, norovirus infection, campylobacteriosis, hepatitis A, and botulism.
45
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)
46
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.
47
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.
48
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.
49
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.
50
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.
51
Types of food fermentations
1. Lactic acid fermentation: Lactose to lactic acid in yogurt production
2. Alcoholic fermentation: Grape sugars to ethanol in wine fermentation
3. Acetic acid fermentation: Ethanol to acetic acid in vinegar production
4. Ethanol fermentation: Sugars to ethanol in biofuel production
5. Malolactic fermentation: Malic acid to lactic acid in winemaking
6. Propionic acid fermentation: Lactic acid to propionic acid in Swiss cheese production
7. Butyric acid fermentation: Lactic acid to butyric acid in fermentation of certain cheeses
52
________ require high level of salt to grow
Halophiles
53
To keep microbe out is called
Aseptic
54
_______ are multicellular, filamentous microorganisms
Moulds
55
_________ is a measure of acidity or alkalinity of a solution
PH
56
Natural and man-made substances added to food for an intended purpose are _________
Food additives
57
The radiation used in laminar flow benches are _________
Uv radiation
58
A temperature of 121° C for 15 minutes is used for sterilization in _______
Autoclave.
59
Use of heat is _______ method of sterilization
Physical method of sterilization
60
Highlight the need of rapid detection technique
Rapid detection techniques are crucial for quickly identifying and controlling foodborne pathogens, reducing the risk of foodborne illness outbreaks, minimizing economic losses, and maintaining consumer confidence in food safety. it's quick
61
What are foodborne viral diseases?
Foodborne viral diseases include norovirus infection, hepatitis A, rotavirus infection, hepatitis E, and enterovirus infections. They cause symptoms such as gastroenteritis, jaundice, diarrhea, vomiting, fever, and abdominal pain, and are transmitted through contaminated food or water.
62
What is water activity
Water activity (aw) is a measure of the amount of water available for microbial growth in a food product. It represents the ratio of the vapor pressure of water in a food to the vapor pressure of pure water at the same temperature. Foods with higher water activity levels (closer to 1.0) provide better conditions for microbial growth and are more prone to spoilage.
63
Explain Proteolysis
Proteolysis is the breakdown of proteins into smaller components, usually carried out by enzymes called proteases.proteolysis can contribute to desirable changes such as tenderization of meat or development of flavor in fermented nroducts like cheese and cured meat
64
What is selective media?
Selective media are culture media designed to grow specific types of microorganisms while inhibiting others. They achieve this by incorporating ingredients that favor the growth of desired microbes while suppressing unwanted ones.
65
What is mycotoxin
Mycotoxins are toxic compounds produced by certain molds (fungi) that can contaminate food and feed crops. health risks to humans and animals when ingested, inhaled, or absorbed through the skin. Common mycotoxins- aflatoxins, ochratoxin A, fumonisins, and deoxynivalenol (DON), among others. effects - acute poisoning, chronic health problems, and even carcinogenicity.
66
What is bacterial growth curve?
The bacterial growth curve shows the growth phases of bacterial populations: lag phase, log phase (exponential growth), stationary phase, and death phase.
67
Factors that will affect the growth of bacteria
1. Temperature
2. pH
3. Moisture
4. Nutrient availability
5. Oxygen concentration
6. Presence of inhibitors or antimicrobial agents
7. Physical factors such as light and pressure
68
Types of spoilage associated with canned food
Types of spoilage associated with canned food include swelling or bulging cans, leaking or damaged cans, off-odors or off-flavors, discoloration, texture changes, presence of molds, and botulism.
69
What is botulism ?
Botulism is a severe illness caused by a toxin produced by Clostridium botulinum bacteria. It leads to muscle weakness, paralysis, and can be life-threatening. It's often associated with improperly canned or preserved foods.
70
Few functional aspects of fermented food
Functional aspects of fermented foods include enhanced digestibility, increased nutrient bioavailability, preservation, flavor development, texture improvement, probiotic activity, and reduction of antinutrients.
71
What's the difference between gram positive and gram-negative cell walls?
Gram-positive cell walls have a thick layer of peptidoglycan and retain the purple stain in the Gram staining process, while Gram-negative cell walls have a thinner layer of peptidoglycan, an outer membrane, and do not retain the purple stain.
72
What is most probable number?
The Most Probable Number (MPN) is a statistical method used to estimate the concentration of viable microorganisms in a sample when traditional plate counting methods are impractical. It involves inoculating multiple tubes or wells with different dilutions of the sample and observing growth or absence of growth. Based on the pattern of positive and negative results, the MPN is determined using statistical tables or software.
73
What is BSE?
BSE stands for Bovine Spongiform Encephalopathy, which is a progressive neurological disorder affecting cattle. It is commonly known as "mad cow disease." BSE is believed to be caused by abnormal proteins called prions that affect the brain and spinal cord of infected cattle. It can be transmitted to humans through the consumption of contaminated beef products, leading to a similar fatal neurological disease called variant Creutzfeldt-Jakob Disease (vCJD).
74
What is sporulation?
Sporulation is the process by which certain types of bacteria and fungi form specialized reproductive structures called spores. These spores are highly resistant to harsh environmental conditions, such as heat, desiccation, and chemical exposure, allowing the microorganism to survive unfavorable conditions. Sporulation is a survival strategy that enables the organism to remain dormant until conditions become more favorable for growth and reproduction.
75
Explain endotoxin and exotoxin
Endotoxins and exotoxins are both bacterial toxins, but with key differences. Endotoxins are part of the cell wall of gram-negative bacteria and released upon cell death, causing a general inflammatory response. Exotoxins are proteins secreted by various bacteria and can have specific, often severe effects on the body.
76
Explain antibiotic and antiseptic
Antiseptics and antibiotics are both used to fight microorganisms,
* Antiseptics are applied topically to skin or surfaces to reduce the number of microorganisms and prevent them from causing infections. They are not meant to be ingested and can be irritating to tissues. Common antiseptics include alcohol, iodine, and hydrogen peroxide.
* Antibiotics are medications that kill or inhibit the growth of bacteria inside the body. They are typically taken by mouth or injected and are prescribed to treat existing infections.
77
What is zymology?
Zymology is the scientific study of fermentation, the process by which microorganisms like yeast and bacteria break down sugars in the absence of oxygen. This process produces a variety of products, including alcohol, acids, and gases. Zymology has applications in various fields, including brewing, winemaking, food production, and biofuels.
78
What is listeria?
Listeria is a type of bacteria that can cause food poisoning. It can be especially harmful for pregnant women, newborns, older adults, and people with weakened immune systems.
79
What is an indole test?
The indole test is a microbiological assay used to detect an organism's ability to produce indole from tryptophan. After growing the bacteria in a tryptophan-rich medium, Kovac's reagent is added. A positive result is indicated by a red color, showing that the organism produces indole. This test helps in identifying and differentiating bacteria, especially within the Enterobacteriaceae family.
80
Difference between differential media VS selective media
- **Differential Media**: Distinguishes between different microbes based on their biological reactions, often using color changes. Example: MacConkey agar.
- **Selective Media**: Inhibits the growth of certain microbes while allowing others to grow. Example: Mannitol salt agar selects for Staphylococcus species.
81
Difference between antioxidant and antimicrobial
- **Antioxidants**: Substances that prevent or slow damage to cells caused by free radicals and oxidative stress. Example: Vitamin C.
- **Antimicrobials**: Agents that kill or inhibit the growth of microorganisms like bacteria, viruses, fungi, or parasites. Example: Penicillin.
82
What is difference between mesophile and psycrophiles
- **Mesophiles**: Microorganisms that thrive at moderate temperatures, typically between 20°C and 45°C. Example: E. coli.
- **Psychrophiles**: Microorganisms that thrive at cold temperatures, typically below 15°C, and can grow at 0°C. Example: Pseudomonas.
83
Define symbiotic
**Symbiotic** refers to a close and often long-term interaction between two different biological organisms, where at least one of the organisms benefits. These interactions can be mutualistic (both organisms benefit), commensalistic (one benefits, the other is unaffected), or parasitic (one benefits at the expense of the other).
84
define faculative anaerobes
**Facultative anaerobes** are microorganisms that can grow in both the presence and absence of oxygen. They use oxygen for aerobic respiration when it is available but can switch to anaerobic respiration or fermentation in its absence. This flexibility allows them to thrive in diverse environments.
85
What is microbial mass?
**Microbial mass** refers to the total biomass or quantity of microorganisms in a given environment or sample. It includes the collective weight or volume of all the microbial cells present.
86
Define functional food
**Functional food** refers to foods that provide health benefits beyond basic nutrition, due to the presence of specific nutrients, bioactive compounds, or additives that can enhance overall health or reduce the risk of disease. Examples include probiotics, fortified cereals, and omega-3 enriched products.
87
What is thermoduric microorganisms
Thermoduric microorganisms are bacteria that can survive short exposure to high temperatures. While they may not necessarily grow at elevated temperatures, they possess the ability to withstand heat treatments such as pasteurization. They can be a concern in food processing, as they may survive heat treatments applied to kill pathogenic bacteria, potentially causing spoilage or affecting product quality. Examples include certain spore-forming bacteria like Bacillus and Clostridium species.
88
Few example Of probiotic and prebiotic
**Probiotics**:
1. **Lactobacillus acidophilus**: Found in yogurt, supports gut health.
2. **Bifidobacterium bifidum**: Helps maintain gut balance.
3. **Saccharomyces boulardii**: Prevents/treats diarrhea.
**Prebiotics**:
1. **Inulin**: Found in fruits and veggies like bananas, onions.
2. **Fructooligosaccharides (FOS)**: In asparagus, chicory root.
3. **Galactooligosaccharides (GOS)**: Found in breast milk, some foods.
89
What is botulism?
**Botulism** is a rare but serious illness caused by toxins produced by the bacterium Clostridium botulinum. These toxins attack the nervous system, leading to symptoms such as muscle weakness, paralysis, and potentially respiratory failure. Botulism can be acquired through contaminated food, wounds, or by inhaling the toxin. It's considered a medical emergency and requires immediate treatment.
90
Explain the spoilage of fruits and vegetables by mold
Mold spoilage of fruits and vegetables occurs when mold fungi grow on the surface or inside the produce, breaking down their structure and causing visible signs of spoilage like mold growth, discoloration, and softening.
91
Explain coagulase test
The coagulase test helps identify bacteria, particularly Staphylococcus aureus, by detecting the enzyme coagulase. This enzyme causes clotting in plasma. If the bacteria produce coagulase, the plasma will clot, indicating a positive result. This test is crucial in distinguishing pathogenic from non-pathogenic Staphylococcus species and is used in clinical diagnosis and food safety assessments.
92
Adding acid or base to media is done to adjust________
pH
93
Binary fission is ________ mode of reproduction
Asexual
94
Science of biological classification is________
taxonomy
95
Tempel it's a fermented _______ product
Soyabean (mold called Rhizopus oligosporus.)
96
Catalase is a microbial ________
Enzyme
97
As microorganisms grow they tend to form______
colonies.
98
What is nucleic acid Probes?
Nucleic acid probes are short DNA or RNA molecules that bind specifically to complementary sequences in target nucleic acids, enabling their detection and identification in samples.
99
What are Viral pathogens
Viral pathogens are viruses that cause disease in their host organisms. These microscopic infectious agents invade host cells, replicate, and often cause illness. Examples include influenza virus, HIV, and SARS-CoV-2 (the virus responsible for COVID-19). Viral pathogens can affect humans, animals, and plants, leading to a wide range of diseases.
100
What are foodborne diseases?
Foodborne diseases are illnesses caused by consuming contaminated food or beverages. Contaminants can include pathogens such as bacteria, viruses, parasites, or chemical substances. Common causes of foodborne diseases include Salmonella, E. coli, norovirus, and Listeria. Symptoms often include nausea, vomiting, diarrhea, and abdominal pain. Prevention involves proper food handling, cooking, and storage practices.
101
______ is not a natural environment for microorganisms
Sterile
102
Microorganisms that causes diseases are called
Pathogens
103
Saccharomyces is an example of
yeast.
104
______ it's inactive or dormant state of roadshape bacteria
Endospore (Bacillus and Clostridium species)
105
Common method of food prevention
1. **Refrigeration and Freezing**: Slows down microbial growth and enzymatic activity by keeping food at low temperatures.
2. **Canning**: Seals food in airtight containers and heats them to destroy microorganisms.
3. **Drying**: Removes moisture from food, inhibiting the growth of bacteria, yeast, and molds.
4. **Salting and Sugaring**: Uses high concentrations of salt or sugar to create an inhospitable environment for microorganisms.
5. **Pickling**: Preserves food in an acidic solution, typically vinegar, which inhibits microbial growth.
6. **Fermentation**: Uses beneficial microorganisms to convert sugars into acids or alcohol, which act as preservatives.
7. **Pasteurization**: Briefly heats food to kill harmful bacteria without significantly affecting its quality.
8. **Vacuum Packing**: Removes air from the packaging to limit the growth of aerobic microorganisms.
106
What is camp test
The Camp test is a microbiological assay used to differentiate between Streptococcus agalactiae and other beta-hemolytic streptococci by observing enhanced hemolysis in the presence of Staphylococcus aureus.
107
What are foodborne diseases and agents
Foodborne diseases are illnesses caused by consuming contaminated food or beverages. Agents include bacteria (e.g., Salmonella), viruses (e.g., norovirus), parasites (e.g., Cyclospora), and toxins (e.g., Staphylococcus aureus).
108
What is biochemical test
Biochemical tests are lab techniques to identify microorganisms based on their metabolic reactions. Examples include catalase test and oxidase test & gram staining.
109
Geotrichum is a
Dairy mold
110
Aflatoxin
Aspergillus
111
Coxiella
Rickettsiae
112
Zygosaccharomyces
Yeast
113
Halophiles
Salt-tolerant microorganisms
114
Indole test
Test to identify bacteria
115
EMB Agar
Differential media
116
What is the log phase in bacterial growth
a phase of bacterial growth that is characterized by cell doubling through binary fission. During this phase, the number of new bacteria that appear per unit of time is proportional to the current population. For example, E. coli can double every 20 minutes in the log phase.
117
What is flow Cytometry?
Flow cytometry is like a high-tech cell sorter. It shines a laser on cells as they flow past. By measuring the light they scatter and the fluorescence they emit, it can tell us a lot about their size, shape, and what molecules they have. This helps scientists study and sort cells for research, diagnosis, and treatment.
118
What is immunoprecipitation method?
Immunoprecipitation isolates a specific protein from a mixture using an antibody that binds to the target protein, followed by precipitation and purification steps.
119
What is shellfish poisoning?
Shellfish poisoning refers to illnesses caused by consuming shellfish contaminated with toxins produced by certain algae, bacteria, or other organisms. There are several types of shellfish poisoning, including:
1. **Paralytic Shellfish Poisoning (PSP)**: Caused by toxins produced by dinoflagellates such as Alexandrium spp. Symptoms include tingling or numbness in the mouth, dizziness, nausea, and paralysis.
2. **Amnesic Shellfish Poisoning (ASP)**: Caused by the toxin domoic acid, produced by certain diatoms such as Pseudo-nitzschia spp. Symptoms include short-term memory loss, confusion, and seizures.
3. **Diarrhetic Shellfish Poisoning (DSP)**: Caused by toxins such as okadaic acid and dinophysistoxins, produced by certain species
120
What is a foot parasite?
Food parasites are organisms transmitted through contaminated food or water. Examples include Toxoplasma gondii from undercooked meat and Cryptosporidium spp. from contaminated water, causing illnesses like toxoplasmosis and cryptosporidiosis.
121
One eg of Enrich media
Blood agar
122
What is biopreservation?
Biopreservation is using natural or controlled microbiological processes to preserve food, often by inhibiting spoilage organisms or pathogens with beneficial microorganisms or their products.
123
What is thermostable nuclease test
The thermostable nuclease test is a laboratory test used to detect the presence of the enzyme thermostable nuclease, which is produced by certain bacteria, particularly Staphylococcus aureus
124
What is temperature danger zone?
(4°C to 60°C). Foodborne bacteria can multiply rapidly in this temperature range, making it important to keep food out of the danger zone to prevent foodborne illness.
125
What is shigellosis?
Shigellosis is an intestinal infection caused by a group of bacteria called Shigella. It causes diarrhea, stomach cramps, fever, and sometimes bloody stools. Shigella is very contagious and can be spread easily from person to person through contaminated food or water, or by not washing hands properly.
126
Explain Catalase test
The catalase test is a microbiological test used to identify bacteria that produce the enzyme catalase. This enzyme breaks down hydrogen peroxide (H2O2) into water and oxygen gas.
The presence of bubbles after adding hydrogen peroxide to a bacterial sample indicates a positive catalase test, meaning the bacteria produce catalase. This test is a simple and quick way to differentiate between certain types of bacteria.
127
What do you mean by ropiness of bread?
Ropiness in bread is a spoilage issue caused by certain bacteria, most commonly Bacillus subtilis and Bacillus licheniformis. These bacteria are heat-resistant and can survive the baking process. When conditions are favorable, such as warm temperatures and high moisture content, these spores germinate and the bacteria start to grow.
The bacteria produce enzymes that break down the bread's starches and proteins, resulting in a sticky, stringy crumb. The bread may also develop an unpleasant fruity odor. Ropy bread is not safe to eat and should be discarded.
128
Saccharomyces is a
Yeast
129
Types of media
1. **Enriched Media**: Contains beef extract or peptone to support the growth of a wide range of microorganisms.
2. **Selective Media**: Contains components that inhibit the growth of certain microorganisms while allowing others to grow.
3. **Differential Media**: Contains indicators for distinguishing between different types of microorganisms based on their biochemical properties.
4. **Minimal Media**: Contains only essential nutrients required for the growth of microorganisms, used for specific research purposes.
130
Few examples of disease caused by natural toxins
**Mushroom Poisoning**: Mushroom poisoning occurs when individuals ingest toxic mushrooms containing various harmful compounds. Examples of mushroom toxins include:
1. **Amatoxins**: Found in certain Amanita species like Amanita phalloides (Death Cap), amatoxins cause liver and kidney failure, leading to symptoms such as nausea, vomiting, diarrhea, abdominal pain, and ultimately, death if untreated.
2. **Gyromitrins**: Found in false morels (Gyromitra spp.), gyromitrins can cause symptoms such as vomiting, diarrhea, abdominal pain, and in severe cases, neurological symptoms and death.
3. **Muscarine**: Found in certain species of Inocybe and Clitocybe mushrooms, muscarine can cause symptoms like excessive sweating, salivation, tearing, blurred vision, vomiting, diarrhea, and abdominal pain.
**Shellfish Poisoning**: Shellfish poisoning occurs when individuals consume shellfish contaminated with toxins produced by certain algae or bacteria. Examples include:
1. **Paralytic Shellfish Poisoning (PSP)**: Caused by toxins produced by dinoflagellates such as Alexandrium spp., leading to symptoms such as tingling or numbness in the mouth, dizziness, nausea, and paralysis.
2. **Amnesic Shellfish Poisoning (ASP)**: Caused by the toxin domoic acid, produced by diatoms such as Pseudo-nitzschia spp., resulting in symptoms like short-term memory loss, confusion, and seizures.
3. **Diarrhetic Shellfish Poisoning (DSP)**: Caused by toxins such as okadaic acid and dinophysistoxins, produced by dinoflagellates like Dinophysis spp., leading to symptoms such as diarrhea, stomach cramps, nausea, and vomiting.
These are brief explanations of mushroom poisoning and shellfish poisoning, both caused by ingestion of toxins present in the respective organisms.
131
What is bacteriocin
Bacteriocins are antimicrobial peptides or proteins produced by bacteria inhibit the growth of closely related or competing bacteria. These compounds are part of the bacterium's defense mechanism against other bacteria in its environment
132
What are food acids What are food assets?
Food acids are acids commonly found in foods and beverages that contribute to their taste, preservation, and stability. They can occur naturally in foods or be added during processing. Some common food acids include:
1. **Citric Acid**: Found naturally in citrus fruits like lemons, oranges, and limes. It is often used as a flavoring agent and preservative in foods and beverages.
2. **Lactic Acid**: by fermentation of lactose by lactic acid bacteria. in fermented foods like yogurt,
3. **Acetic Acid**: Found in vinegar,
4. **Malic Acid**: naturally found in fruits like apple
5. **Tartaric Acid**: naturally found in fruits like grape
133
What is enteropathogenic organism?
Enteropathogenic organisms are microorganisms that cause gastrointestinal infections, leading to symptoms like diarrhea, vomiting, and abdominal pain. Examples include bacteria (e.g., E. coli, Salmonella), viruses (e.g., norovirus, rotavirus), and parasites (e.g., Giardia, Cryptosporidium).
134
What is virulence
Virulence refers to the degree or intensity of pathogenicity of a microorganism, meaning its ability to cause disease or damage to a host organism
135
Explain MBRT
MBRT is a microbiological test to assess how well filters remove microorganisms from liquids. It involves passing liquid through a filter membrane, which traps microorganisms. The membrane is then incubated to count the trapped microorganisms, ensuring product quality and safety in industries like pharmaceuticals and food production.
136
What is impedance?
impedance measures the electrical resistance of a culture medium containing microorganisms, which changes as the microorganisms grow and metabolize nutrients. This method is commonly used in automated microbial detection systems to monitor bacterial or fungal growth in various applications, such as food safety testing, pharmaceutical quality control, and clinical diagnostics
