Food Microbiology Flashcards
Known as the “Father of Microbiology” and the first to observe yeast cells, and also the first to observe bacteria and protozoa
Antonie van Leeuwenhoek
Invented the canning process
Nicolas Appert
Who patented the tin can?
They issues a British patent to preserve food in glass, pottery, tin & o
Peter Durand
Who issued a patent for steam sterilization (retort)
Raymond Chevallier-Appert
Invented the gram staining technique
Hans Christian Gram
Invented the petri dish
Julius Richard Petri
They demonstrated that living organisms cause lactic and alcoholic fermentations
Louis Pasteur
Who was the first person to isolate Salmonella eneteritidis from meat which caused 57 cases of food poisoning?
A.A. Gaertner
________ is passed in response to Upton Sinclair’s expose of the meat industry in this book, The Jungle
it is an act, series of guidelines
Food and Drug Act (FDA)
________ first used the term psychrophile for microorganisms that grow at 0 deg C
Schmidt-Nielsen
identify the bacteria
During the 1900s, ________ caused food poisoning and the first case of diphyllobothriasis was recognized
Bacillus cereus
The term osmophile was coined by ____ for yeasts that grow well in areas of high osmotic pressure
Richter
B.W. Hammer first isolated ________ from coagulated milk
Bacillus coagulans
Who was the first to isolate Geobacillus stearothermophilus from cream-style corn?
P.J. Donk
During the 1930s, outbreaks of ________ were traced in milk, which lead to the introduction of home refridgerators
Campylobacter enteritis
identify 2 contributors
These persons demonstrated that perfringens food poisoning is caused by a toxin which lead to Turkey X disease outbreak
think of dunkin donuts and superman
C. Duncan and D. Strong
identify the disease
In the 1980, foodborne outbreak ____ occurred in the US which was caused by L. monocytogenes
Listeriosis
idenitfy the bacteria
In 1980, ____ was also first recognized as a pathogen
very common, think of fecal contam
E. coli
In the year 1980, ____ were also discovered
misfolded proteins
prions
In 1960, the first commercial facility in the US was designed for ____
a process for extending shelf-life of food
Food Irradiation
____ was approved for pathogen control in meat and poultry in the 2000s
a process, think of food safety
Irradiation
identify the diease/outbreak
In 2000, the first report of ____ disease was reported in the US
Mad Cow disease
identify kind of processing
This processing was indicated by the USDA in 2000, to be used for meat, poultry, processed egg products
High Pressure Processing
In year 2000, this act was passed which provides preventative controls for both human and animal foods
Food Safety Modernization Act
It is the ratio the water vapor pressure of food substrate to the vapor pressure of pure water at a certain temp
Water activity
name the bacteria
A water activity of 0.86 or greater indicates the potential growth of ______.
Staphylococcus aureus
This refers to the tendency of a substance to accept or donate electrons. It is also related to the availability of O2.
an intrinsic parameter
Oxidation-Reduction Potential (ORP) or Redox Potention (Eh)
Low ORP values (more negative) are associated with anaerobic conditions which gives way to spoilage microbes like ________
C. botulinum
identify bacteria species
High ORP values (more positive) are associated with aerobic conditions which supports growth of _______
Pseudomonas spp.
Enumerate the extrinsic parameters of food
extrinsic - storage environment of food
- Temperature
- Humidity
- Atmospheric conditions
- Presence and concentration of Gases
- Presence and activity of other microorganisms
fill in the blanks
Identify the antimicrobial constituents present in the ff:
____ in cloves
____ & ____ in milk
____ in garlic
____ in eggs
- eugenol
- casein and lysozyme
- allicin
- conalbumin
List the intrinsic parameters of food
- pH
- Moisture content and water activity
- Antimicrobial constituents
- Nutrient content
- RedOx potential (Eh)
- Biological structures
They have the widest pH tolerance
Molds
These microorganisms have relatively high pH tolerance
Yeasts
They have the narrowest pH tolerance
Bacteria
A water activity that is greater than 0.86 indicates _______.
it’s an acronym
PHF (potentially hazardous food)
Fruits generally undergo ____ spoilage
mold and yeast
Meats and seafoods have a final pH greater than 5.6, making them susceptible to ______ and ________ spoilage
bacterial and fungal
Clostridium botulinum can grow in low-acid foods, with pH of ____.
less than 4.6
This is the available water for use by biochemical reactions
Water activity
This is an inhibitory system which naturally occurs in bovine milk. It is used in the preservation of raw milk when refrigeration units are absent
Lactoperoxidase system
The lactoperoxidase system consists of 3 things:
- lactoperoxidase
- thiocyanate
- H2O2
In the lactoperoxidase system, antimicrobial agents are bacteriostatic against ______
two different cell types, think of math signs
Gram + bacteria
In the lactoperoxidase system, antimicrobial agents are bactericidal against ______.
think of math signs; it refers to cell type
Gram - bacteria
What is the range of TDZ (temperature danger zone)?
4-60 deg C or 40-140 deg F
____ is the most important gas used to control microbes in foods
CO2
This gas also has antimicrobial properties however it is also strongly oxidizing
O3
Some organisms produce substances which are lethal/inhibitory to others such as:
- Antibiotics
- Bacteriocins (e.g. Nisin)
- Organic acids
- H2O2
Known as “barrier technology” and uses multiple techniques to inhibit microbial growth and extend the shelf life
Hurdle technology
State the 3 types of hurdles:
referring to hurdle technology
- Physical hurdles
- Physico-chemical hurdles
- Microbially-derived hurdles
choose which bacterial species
The predominant microbiota in meat are the following except: Staphylococcus, Micrococcus, Pseudomonas, some yeasts and molds, Campylobacter spp.
Campylobacter spp.
Predominant micobiota in poultry are mostly psychrotrophic bacteria primarily ____ and ______ species
Acinetobacter and Moraxella species
describe the characteristic of fungal spoilage
Thamnidium, Mucor and Rhizopus species cause ____ in food
whiskers
Cladosporium exhibit ____ in food
black spots
Geotrichum, Sporotrichum exhibit ____ in food
white spots
Green patches in foods are caused by ______.
Penicillium, Aspergillus
state the bacteria spp.
Souring (anaerobic spoilage) is caused by bacteria such as:
1. ____
2. ____
3. ____
- LAB
- clostridia
- coliforms
Predominant microbiota in finfish varies depending on the environment. Psychrotrophic bacteria such as Acinetobacter, Aeromonas, Shewanella, Flavobacterium, Pseudomonas, Vibrio thrive in ________ waters.
Temperate
Mesophilic bacteria such as Bacillus, coryneforms, Micrococcus thrive in ____ waters.
Tropical and subtropical waters
Predominant microbiota in shelfish depends on the quality of water. Includes the ff. except:
* Shewanella putrefaciens
* Pseudomonas spp.
* Acinetobacter
* Salmonella spp.
* Moraxella
All except Salmonella spp.
A type of differential staining technique to differentiate bacteria into two major groups based on the structure of their cell walls
Gram staining
Gram + bacteria will appear ____ under the microscope, indicating a thick peptidoglycan in cell wall
Blue or purple
Gram - bacteria will appear ____ under the microscope which indicates a thinner peptidoglycan layer in cell wall
Red or pink
Enumerate the steps in Gram staining
- Primary stain is applied (crystal violet)
- Mordant is applied (Gram’s iodine)
- A decolorizer is applied (Ethyl alcohol)
- Counterstain is applied for the last step (safranin)
What are the steps of Endospore staining?
- Primary stain (malachite green)
- Mordant (heat)
- Decolorizer (water)
- Counterstain (safranin)
Enumerate the kinds of biochemical tests for bacterial microorganisms
- Catalase test
- Oxidase test
- Carbohydrate Fermentation test
- IMViC test
- Motility Test