Food Microbiology Quiz 1

Front 1

what are the characteristics of a gm + bacteria?

Back 1

1. Have a Cell Wall
2. Cell Wall is Thick
3. Lack an outer membrane
4. Stain purple

Front 2

what are the characteristics of a gm - bacteria?

Back 2

1. Have a Thin Cell Wall
2. Has an outer membrane composed of a phospholipid bilayer
3. Stains Pink

Front 3

what is an aerobic bacteria?

Back 3

has an O2 based metabolism

Front 4

what is a facultative anerobe?

Back 4

are anerobic bacteria, but can grow also when O2 is present. Basically, they grow in both environments

Front 5

what is an anerobe

Back 5

grows in environments that lack O2

Front 6

what are rickettsias?

example?

Back 6

non-motile, gm -, non-sporeforming bacteria that require a host to grow.

(depend on cytoplasm of euk. host)

example: Rickettsia typhi

Front 7

what is a cocci bacteria?

Back 7

spherical shaped

ex. staphylococcus

Front 8

what is an endospore?

Back 8

dormant, tough, non reproducing structures that are produced by bacteria for survival in non-optimal environments.

ex: Cloistridium botulinium

Front 9

what is an example of a gm - endospore forming rod?

Back 9

Listeria

Front 10

what is a thermophilic bacteria?

Back 10

grows in high temp env.

Front 11

what is a psychrotropic bacterium?

Back 11

bacterium that can grow at 0C but prefer 40-70C range. particularly concerning for food spoilage.

Front 12

what is a thermoduric bacterium?

Back 12

bacteria that can survive high temperatures, particularly pasteurization.

Front 13

what is a halotolerant bacteria?

Back 13

bacterium that can grow best in the absence of NaCl, but can still grow when mod. conc.'s are present.

Front 14

what is a aciduric bacterium?

Back 14

bacteria that can tolerate highly acidic environments.

Front 15

what is a osmophilic bacterium?

Back 15

bacteria that prefer to grow in env.'s of high osmotic pressure.

Front 16

Who contradicted spontaneous generation in 1765?

Back 16

Leuweenhoek. Boiled meat in sealed flask, saw no growth.

Front 17

Who invented canning in 1804?

Back 17

Appert. He developed the sealed container therma process (canning). He developed it for a 10000 prize that Napolean offered to prevent food spoilage at war.

Front 18

Who further refined the canning process to use tin? What year?

Back 18

Durand, 1819.

Front 19

Who was JT Snow?

Back 19

Recognized cholera in 1849. Drinking water issue in britain.

Front 20

Describe Pasteurs notable discoveries and the years.

Back 20

1860-fermentation was due to yeast and bact. Disproved spon. generation.

1870- Developed mild heating process for preservation (pasteurization). Originally developed for wine industry.

Postulated GERM THEORY FOR DISEASE--infections due to micro-organisms.

Developed ANTHRAX and RAIBES vaccines.

Front 21

Describe Koch's major discoveries.

Back 21

-Isolated Vibrio cholera
-Developed solid media(agar), petri dish, and steam sterilization. (autoclave)

-Created KOCHS POSTULATES
1.Isolate agent from patient
2. Grow in lab
3. Infect healthy subject
4. Subject must develop symptoms

Front 22

what are the characteristics of prokaryotes?

Back 22

no nucleus
singular chromosome (DNA)
usually unicellular

Front 23

describe characteristics of yeast

Back 23

eukaryotic, cell walls made of glycan

cell size = 2-30um

fungi group

unicellular, oval, spherical, or elongated

nonmotile

Front 24

describe characteristics of molds

Back 24

euk.

rigid cell walls (made of chitin or cellulose)

lack chloroplasts

Front 25

describe characteristics of protozoa

Back 25

euk.

quite motile

no cell walls or chloroplasts

usually unicellular

Front 26

describe characteristics of viruses

Back 26

made of non-cellular genetic elements

size = 0.1um

obligate parasite - needs cells to replicate viral particles

Front 27

what are beneficial food microbes?

deleterious? innocuous?

Back 27

beneficial:
food fermentators
probiotics

deleterious:
pathogens
spoilage

innocuous:
dont do anything relevant

Front 28

Name all of the Pathogenic Bacteria in Foods

Back 28

Aeromonas, Arcobacter, Bacillus, Campylobacter, Clostridium, Escherichia, Listeria, Salmonella, Shigella, Staphylococcus, Streptococcus, Vibrio, Yersina

Front 29

Name a disease associated with the pathogens listed above in food.

Back 29

Aeromonas - Diarrhea, severe sickness in children

Arcobacter - Campylobater species, diarrhea. Spread through animals

Bacillus - Bacillus cereus, vomiting and diarrhea. Short duration of illness

Campylobacter - Diarrhea

Cloistridium - Botulism, canned foods anerobic, diarrhea, double vision, suffocation, Gm+

Escherichia - diarrhea, kidney disease, meats (cow)

Listeria - Milk prod, immunocompromised adults, causes septicimia, meningitis, monocytogenes is species. Gm+

Salmonella - diarrhea, meats

Shigella - bloody diarrhea (dysentary)

Stapylococcus - aureus, vomiting, diarrheam nausea, Gm+

Streptococcus - pyogenes

Vibrio - seafood (oysters), usually from fecal source. makes. fever, chills, nauseas. Vibrio vulnificus

Yersina - enterocolitica, diarrhea

Front 30

What is another name for microbial growth?

Back 30

Binary Fission

Front 31

What is the equation used for predicting binary growth?

Back 31

N=No(2)e+(t-to)/G

Front 32

Name all the phases of a microbial growth curve

Back 32

Lag Phase, Exponential Phase, Stationary Phase, Death

Front 33

What is Symbiotic, Synergistic and Antagonistic Growth?

Back 33

Symbiotic=Require each other
Synergistic=Complement Each other, faster together
Antagonistic=Inhibit

Front 34

How do we measure growth?

Back 34

Generation Time, Specific Growth

Front 35

Name Intrinsic Factors that Affect Growth.

Back 35

pH, aW, Nutrient Content, Oxi-Red Potential, Presence of Anti-Microbials

Front 36

Why can't bacteria grow at a very low pH?

Back 36

Because the protiens of the bacteria have an optimal pH value to catalyze reactions in order for reproduction. (more H+ diffuses in cell than H+ pump can pump out)

Front 37

Name differences between yeast and algae

Back 37

•Yeast have no chloroplasts
•Yeast are non-motile
•Yeast are relevant in food microbiology, algae aren't

Front 38

Name differences between yeast and mold

Back 38

Yeasts are mostly unicellular, Molds are usually multicellular
Yeast cell wall made of glycans, molds of chitin

Front 39

Discuss three differences and two similarities between an ELISA and a lateral-flow device.

Back 39

Differences:
• ELISA requires several steps, LFD does not
• ELISA uses enzymes as reporters, LFD does not (use latex particles)
• ELISA is slower than LFD
• LFD is simpler than ELISA
• ELISA is more sensitive than LFD
Similarities:
• Both use at least two set of antibodies
• Both use the sandwich format
• Both are immunoassays
• Both are qualitative methods

Front 40

7. What are the characteristics that make the 16s RNA genes ideal as a phylogenetic molecule?

Back 40

Mention at least 3 of the following 4:
•It is highly conserved
•It is present in all bacteria (universally present)
•It is easy to obtain
•It has multiple copies

Front 41

What are the differences between the activated and germinated stage of the sporeformer cycle?

Back 41

The germination stage has synthesis of amino acids & nucleotides, RNA and protein synthesis, cell wall and membrane synthesis, and DNA replication