Food microbiology Flashcards
(88 cards)
1
Q
HTST
A
high t, short time
2
Q
Why canning?
A
increase shelf life at room temperature
3
Q
How to can acidic food?
A
T: 100 C
4
Q
How to can non acidic food?
A
autoclave: 121 C
5
Q
What is 12D process?
A
10^12 spores of Clostridium botulinum killed
6
Q
How to take out water to inhibit growth?
A
- sun dry
- hot air drying
- freeze-drying (lyophilization) result in little lost of quality but is really expensive
7
Q
Irradiation
Radappertization
A
kill ALL microorganism
8
Q
Irradiation
Radicidation
A
kill SPECIFIC microorganisms
9
Q
Irradiation
Radurization
A
reduce overall contamination
10
Q
Purpose of nitrites
A
prevent growth of clostridium botulinum
present in celery extract (natural)
11
Q
Purpose of sulfites
A
-wine industry
=inhibits wild yeast
12
Q
What produces Nisin
A
lactococcus lactis
13
Q
What is a primary metabolite
A
a metabolite produced during exponential growth
14
Q
What is a secondary metabolite
A
produced when microorganisms are in the stationary phase
-competition
15
Q
Is a fermentor like a chemostat?
A
YES
16
Q
What does a fermentor control? (4)
A
- temperature
- nutrients
- pH
- dissolved oxygen
17
Q
Gmo to produce 2 things (that we learned)
A
Insulin
rennet (baby cows)
18
Q
Staphylococus areus : endotoxin or exotoxin
A
exotoxin
food poisoning
19
Q
E. Coli : endotoxin or exotoxin
A
endotoxin
infection
20
Q
Salmonellosis : food poisoning or infection
A
infection
endotoxin
21
Q
C botulinum in adults : infection of food poisoning
A
food poisoning
22
Q
C botulinum in infants : infection of food poisoning
A
infection
23
Q
What type of yeast to produce a good beer?
A
Saccharomyces cerevisiae
24
Q
In fermented products, what are the types of microorganisms the most often used?
A
lactic acid bacteria
yeasts
25
Define Lactic acid bacteria (4 characteristics)
- GRAM +
- AEROTOLERANT ANAEROBES
- Rods or cocci
- homofermentative or heterofermentative
26
Homofermentative and heterofermentative both produce
Lactic acid
27
Homofermentative (some food)
pickles,
| sauerkraut = choucroutte
28
Heterofermentative (some food)
Sausages (Salami)
| fermented milk products
29
Name 2 yogurt cultures
Streptococcus thermophilus
| Lactobacillus bulgaris
30
Curdling of cheese : what does precipitate the cheese to make a curd?
Lactic acid bacteria
31
Ripening of cheese : what adds flavor?
lactic acid bacteria and other organisms
32
What cleaves casein?
Lactic acid bacteria or rennin
33
Principal steps to make cheese (5)
```
1 add starter culture
2 add rennin or lactic acid bacteria
3 whey is drained off
4 heat it, not eat it
5 add salt (optionnal)
```
34
Cheese ripening
| Cheddar : what bacteria do we add
lactic acid bacteria
35
Cheese ripening
Swiss cheese : what bacteria do we add for holes
how much time required for ripenning?
Propionibacteria
| 3-12 months or longer
36
Cheese ripening
Blue and roquefort : what bacteria do we add
how much time required for ripenning?
Penicillium roquefort
the molds grows in the holes and produces spores (blue)
and takes (3-6 months)
37
Cheese ripening
Brie <3 and Camembert : what bacterias do we add
How long is the ripening process?
Penicillium
Brevibacterium (on surface)
1-5 months
38
Wine
| What do we add to kill the yeast?
MEtabisulfite
39
Wine
Max percentage of alcohol
(without adding alcohol in the wine)
12-14 %
40
Dry wine... is all the sugar fermented?
yes
41
Sec wine... is all the sugar fermented?
no
42
Vinegar (process of fermentation or not)
no
43
vinegar
| ethanol= acetaldehyde=
acetic acid
44
Glutenberg contains gluten ?
no ;)
45
How do we call the mash when it is filtered?
WORT
46
Lager beer : what strain
Saccharomyces carlsbergensis
47
Ale beer : what strain
Saccharomyces cerevisiae
48
Page beer : what strain
LOL
49
name the Gin from mtl?
Ungava
50
What grain
| vodka
wheat rye or potato
51
What grain
| Gin
grains or starchy product + juniper oil and other flavor ingredients
52
What sugar
| Rum
sugar cane ( molasses)
53
ALL microorganisms need...
Water,
water is life
drink water
54
aw<0,8 only specialized organism can grow :
| Xerophiles (conditions? )
dry environment
| low osmolarity
55
aw<0,8 only specialized organism can grow :
| Osmophiles (conditions?)
high osmolarity
| high sugar
56
aw<0,8 only specialized organism can grow :
| Halophiles (condition?)
high salinity
57
In what type of food can we find Norovirus if not well stored or handled?
Shellfish
58
Hoes does the NASA treat their food ?
Irradiation
59
GRAS
| antispoilage
Generally recognized as safe :,)
Nitrite
sulfites
nisin
60
What microorganisms are naturally found on cabbage (2)
1- Leuconostoc mesenteroides
| 2- Lactobacillus plantarum
61
What microorganism is used to ferment sausage, salami, bologna and pickles
Lactobacillus plantarum
62
What temperature is the yogurt incubated
42
63
what does the lactic acid bacteria do to the protein
it precipitate the protein : curd
64
how do you call the whey
supernatant
65
What does rennin and lactic acid bacteria do to the casein
they both cleave casein which result in the formation of the curd
66
What is the purpose of ripening (3)
texture
consistency
flavor
67
Oka cheese, what is special about it (2)
during ripening, it is frequently washed, and Geotrichum grows
68
What can we add to the wine (2)
Sugar and organic acid
69
Acetic acid bacteria (aerobe or anaerobe)
aerobe
| so Vinegar is not a product of fermentation
70
What microorganism we use for vinegar
Acetobacter
71
True of False
| Acetic acid bacteria oxidize ethanol to acetic acid- strict aerobes, this is not a fermentation process
true
72
Brewing
| What are the key factors (5)
```
1- water
2- malt
3- hops
4- yeast
5- condition of fermentation (t, time)
```
WMHYF
What my health you face
73
Do yeast digest starch?
no
74
How do you call the process of grains germinating?
Malting
75
How do you call the process of which the grains are dried and crushed?
Malt
76
How do you call the process of soaking the malt in warm water (65c) for 1-2 hr?
mashing
77
What degrades the stach?
amylase
78
What is the Hops used for?
flavor
bitterness
prevents lactic acid bacteria to grow in the final product
79
What is polishing?
filtration, carbonation, pasteurization
80
Is hops in both beer and distilled alcoholic beverages?
only in beer
81
Is a food spoiled necessarily harmful
no, think about the cheese that becomes blue,
| you can cut that part...
82
What pathogens can grow at 4.5 c
Yersina enterocolitica,
Listeria monocytogenes,
Clostridium botulinum
83
What is food infection?
organisms are ingested with the food and multiply in the host.
84
Botulism food : poisoning or infection
food poisoning
| ingestion of the neurotoxin produced by C. botulimum
85
Salmonella enterica : food poisoning or infection
food infection
| grows in you
86
E Coli
| 44.5 c kills it or not
no, it inhibits its growth
| but if you cook it at high temperature, you will kill the it.
87
e. Coli food poisoning or infection
infection
| AB-type exotoxin
88
3 methods to pasteurize milk
LTLT
HTST
UHT
