COMMON FOODBORNE MICROORGANISMS Flashcards
Funcion of microorganisms in foods
- Produce desirable changes in food i.e. Fermentaion, milk cheese,
- Spoilage-undesirable changes in food Of-lavor, odor,changes in texture or appearance of the food i.e.putrefacion of meat
- Health hazard-pathogenic bacteria that cause disease or death
Gram-negaive bacteria
Can be
Aerobic
Microaerophilic
Facultaive
Gram Posiive Bacteria
Can be
Cocci
Rods
Spore formers
example of Gram-negaive bacteria Aerobic:
- Pseudomonas
- Acetobacter
- Acinetobacter
- Moraxella
Pseudomonas Spoilage of
refrigerated foods
Pseudomonas found in
in soil and water
Pseudomonas Found in food
vegetables, meat, poultry, and seafood
Pseudomonas produce
blue green pigments
Converts ethanol to Aceic acid. (Produce vinegar)
Acetobacter
- Distributed in the soil and water
- Found especially in refrigerated fresh products
- Responsible for spoilage of Meat, all types
Acinetobacter
Common contaminate of milk and meat products
Moraxella
Example of Gram-negaive bacteria Microaerophilic :
- Campylobacter (jejuni or coli)
a. Pathogenic
b. Require 3 to 6% oxygen to grow
Example of Gram-negaive bacteria Facultaive :
- Escherichia
- Shigella
- Salmonella
- Erwinia
- Yersinia
is a large family of gram negaive bacieria -Facultaive
Enterobacteriaceae
Shigella is Found in the
intesine of humans
Found in the intesinal contents of humans, animals, birds and insects.
Salmonella
Associated with plants and causes Sot rot in vegetables.
Erwinia
Only one species is associated with foodborne illness . found in environment (ponds, lakes)
One species causes the black plague .
Yersinia
Seafood pathogen
Vibrio
Example of Gram Posiive Bacteria Cocci
- Micrococcus
- Staphylococcus aureus
- Lactococcus
- Enterococcus
- Pediococcus
- Leuconostoc
- Strict aerobes,Gram Positive Bacteria
- Produce orange pigments
- Salt tolerant
- Spoilage of meat, milk
Micrococcus
Produce toxin in the food and the toxin is heat resistance
Staphylococcus aureus
Staphylococcus aureus Found associated with
Skin and Nasal membranes
Homofermentaive
Lactococcus
Lactococcus Produces
lacic acid during growth
Produces diacetyl (buter aroma)
Used in fermentaion to produce Lacic acid
Commonly used for fermentaion of Dairy products
Lactococcus
associated with spoilage of vegetables
Enterococcus • E. faecalis
Homofermentaive
Pediococcus
Lactococcus
Lacic acid producing
Pediococcus
Lactococcus
Starter culture for meat fermentaion
Pediococcus
Used as an indication of sanitation
Enterococcus
Heterfermentaive
Leuconostoc
Used as starter culture for vegetables
Leuconostoc
Leuconostoc Causes
spoilage of vacuum – packaged meat by gas formaion
Leuconostoc Produces
Slim when grown on sucrose
Example of Gram Posiive Bacteria Rods
- Lactobacillus
2. Propionibacterium
Lactobacillus
- Gram positive Bacteria
- Rods ,Facultaive
- Used for fermentaion
- Can cause spoilage by slime formaion
- Can cause spoilage of meat by souring
Propionibacterium Produce
Propionic acid and CO2 .
forms the eyes in Swiss cheese
Propionibacterium
Example of Gram Positive Bacteria Spore formers
Bacillus and Clostridium
Spores are
encapsulated with protein layers that resist heat, radiaion,chemicals, and freezing
Some spore formers cause
foodborne poisoning
Members of the fungi, muli-cellular or unicellular
Molds
Molds produce:
Mycotoxins
Alatoxin
Erogot
Molds of importance in foods muliply by
spores
is the mycelium in Molds
The mass
The mass in molds is composed of
filaments called hyphae
Molds or fungi Found in
decaying organic mater
Yeasts Most are
unicellular
Yeasts Reproduce
by budding
Yeasts such a
Saccharomyces
Candida
Saccharomyces means
sugar fungus
Produces ethanol and CO2 for bread yeast
Saccharomyces
Most common yeasts associated with fresh Ground meat, poultry,turkey
Candida
Candida C. uilis
spoils fruit juices
Viruses Spread by
fecal contaminaion and through food
Most important foodborne viruses are
RNA viruses
Viruses that infect bacteria are called
bacteriophage
Noroviruses cause
gastroenteritis
Viruses such as
Hepaiis A , Noroviruses
Primary contaminaion sources of viruses:
- Water
- Humans
- Fecal