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Introduction to food science > Chapter 8 > Flashcards

Chapter 8 Flashcards

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1
Q

Six main causes of “unsafe” food

A

Presence of disease producing ( pathogenic )

Presence of natural toxins

3.
Presence of extraneous matter (e.g., stones, glass, seeds,
4.
Presence of environmental contaminants (e.g., pesticides, heavy
metals in fish)
5.
Presence of harmful additives
6.
Presence of allergens (puts only certain individuals at

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2
Q

two typesof pathogenic organisms

A

Microorganisms [includes viruses, bacteria, molds, and protozoa (parasites)]

Parasitic nematodes (e.g., trichina worm ””, occurs in rats, pigs, and humans,
responsible for the disease trichinosis)

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3
Q

Examples of natural toxins

A

(e.g., poisonous mushrooms, cyanogenic

glucosides in cassava)

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4
Q

Why everybody is so concerned about food safety, especially the ones producing diseases

A 
Globalization of trade

Trend toward food distribution over a broad geographic area from centralized
production and storage facilities

Emergence of new foodborne pathogens
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5
Q

What was the hamburger disease that then transferred to sprouts, lettuce, and spinach

A

E.g., emergence of the pathogenic strain E. coli O157:H7 in beef (“hamburger
disease”) in the 1980s; subsequent outbreaks were traced to contaminated
sprouts, lettuce, and spinach as well as beef (XL Foods in Alberta in 2012)

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6
Q

What is the rate of food poisoning in US, hospitalization and deaths

A

: 75 million
cases/year in the USA (up to 30 % of the

325,000 hospitalizations, 5000 deaths

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7
Q

Economic costs of food poisoning

A

estimates range from 20 billion to $ 45 billion/year:

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8
Q

Categories of losses from food borne diseases

A 
Healthcare costs

Costs of public health investigations

Lost productivity

Loss of market share (company responsible for an outbreak)

Loss of consumer confidence (can be far reaching)
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9
Q

What is the leading cause of food loss/waste

A

In addition to being a major food safety concern, microbiological
contamination is a leading cause of food loss/waste through
spoilage

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10
Q

According to the FDA, mercury level in canned tuna is 0.126 ppm. In this case,
mercury is an example of ……. contaminant in food. (one word, small letters)

A

Environmental

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11
Q

Microorganisms of concern in food microbiology include

A

bacteria and

fungi (yeasts and molds

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12
Q

Bacteria and fungi can ___ in food

A

These microorganisms can proliferate rapidly in foods.

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13
Q

What type of microogranisms do not proliferate in food

A

Viruses

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14
Q

Within the context of traditional food microbiology, the term
“microorganisms” refers to bacteria and

A

Bacteria and fungi

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15
Q

The particular bacterial/fungal species responsible for foodborne
illnesses (pathogenic microorganisms) ____ those
causing food spoilage .

A

are not the same as

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16
Q

When microorganisms can bee beneficial

A

fermented products: yogurt, cheese, sauerkraut, wine

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17
Q

When milk, meat and vegetables/fruits will be exposed to microbial contamination

A


Milk from a cow is sterile originally but not for long

Meat can become contaminated in the slaughterhouse or by handling after
slaughter.

Bruising of fruits and vegetables during and after harvesting provides
points of entry for microorganisms.

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18
Q

bacteria reproduce by ___ , resulting in an

____ of growth : population can double every 20 30 min.

A

binary fission

exponential rate

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19
Q

What is a routine step in food quality control

A

Microbiological analysis

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20
Q

Microbiological analysis involves

A

It can involve the detection , enumeration , and/or identification of
microorganisms

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21
Q

What is standard plate count

A

: method for general enumeration of

microorganisms (total microbial load).

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22
Q

High total microbial loads are the effects of

A

poor sanitary control in the

production, transport, processing, or storage of the food.

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23
Q

There is a ____ in microbiological standards

A

Upper limit on total microbial load

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24
Q

Standard for grade A raw milk is

A

microbial load is not to exceed 100,000 per milliliter.

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25
Why food poisoning is so difficult to define
 Identification of microorganisms is generally a very slow and complicated process
26
Milk should not be pasteurized before making yogurt or cheese. The natural bacteria is needed for the fermentation process. True/false?
False
27
Bacteria are ___ organisms and can be in the shape of
Bacteria are single cell organisms : they can be spherical, rod shaped, or spiral
28
Dimensions of bacteria
1-4 microns
29
Some bacteria are able to form ___
spores (dormant, largely dehydrated
30
Spores are extremely resistant to
to adverse conditions (e.g., heat) and can | survive without nutrients, making them extremely difficult to destroy.
31
Once environmental conditions are favorable,spores can turn into
vegetative cells they once were.
32
Size of yeasts
20 microns
33
Shape of yeasts
spherical or ellipsoidal
34
Yeasts are employed in ___ because
Yeasts are employed in alcoholic fermentation and leavening of dough (production of CO 2)
35
Molds are larger and more complex than ___
yeasts
36
How molds grow
multicellular filaments called hyphae
37
Are molds bad or good
Molds are very common spoilage organisms but are also employed in some types of cheese production, e.g., mold ripened cheese.
38
How microorganisms are able to degrade food systems
Enzymatically
39
Microbial degradation can result in
textural changes , off flavors (e. g., putrefaction, rancidity), and production of gases, acids, slimes (polysaccharides) , or alcohol
40
 | Almost all microorganisms grow well in (conditions)
high moisture conditions : their capability for growth diminishes with a reduction in moisture levels.  Molds are generally better at growing at lower moisture levels than bacteria or yeasts.
41
Mesophilic, thermophilic,psychrophilic and psychrotropic organisms- conditions
Mesophilic organisms grow best over a temperature range of 20 45 C  Thermophilic (heat loving) organisms grow best at temperatures above 45 C ; some are able to grow at temperatures up to 82 C  Psychrophilic (cold loving) organisms grow best at low temperatures 10 C );  Psychrotrophic organisms are able to grow at refrigerator temperature ( 4 C
42
Oxygen requirements for growth of microorganisms and their names
 Anaerobes grow in the absence of oxygen  Aerobes grow in the presence of oxygen  Microorganisms can be obligate (require aerobic or anaerobic conditions) or facultative (can adapt to either
43
Listeria monocytogenes can grow in refrigerated foods, hence; it is considered ...... bacteria. (one word, small letters)
PSYCHROTROPHIC
44
Foodborne illnesses can generally be classified as ___
food infections or | food intoxications
45
What is food infection
: A pathogenic microorganism establishes itself in the | intestines and causes an infection.
46
What is food intoxication
A toxin produced by the microorganism causes illness; the organism itself is not the cause and may even no longer be present in the food (i.e., it may have been killed
47
Some microorganisms cause illness by a
combination of the two mechanisms : i.e., the organism establishes itself in the intestines and then produces a toxin .
48
Microorganisms are named according to the
genus and species to | which they belong, e.g., Escherichia coli
49
How to recognize genus in the name of bacteria
The genus begins with a capital letter , and this letter is used in the abbreviated form of the name, e.g., E. coli
50
When additional terms follow the italicized name , they refer to a ___
subspecies or to a serotype ; e.g., E. coli O 157 :H 7 is a serotype.
51
Sallmonellosis is caused by
: Infection caused by bacteria belonging to the genus | Salmonella : severe gastrointestinal
52
Sallmonellosis:Estimated number of cases per year in the United States and main vehicle of transmission
1 million | poultry
53
Listeriosis is a ___
Infection caused by the bacterial species Listeria monocytogenes , often termed refrigerator disease ” because this species grows in chilled products .
54
What is the 3 rd leading cause of death | from food poisoning
Listeriosis
55
Listeriosis has been most often associated with
Listeriosis has been most often associated with raw milk cheeses . However, ready to eat meats have recently come to the forefront as vehicles for transmission of L. monocytogenes
56
What are cold cuts
Ready-to-eat meat products
57
Campylobacteriosis is ___
: Infection caused by bacteria belonging to the genus Campylobacter , primarily C. jejuni ; it has become the leading bacterial foodborne infection worldwide. Although campylobacteriosis is usually not serious, it can have long term consequences in some individuals.
58
Prevention (CDC), ~40% of cases of Guillain Barré syndrome are triggered by
serious condition) are triggered by a bout with campylobacteriosis
59
C.jejuni- main vehicle of transmission
poultry, raw chicken
60
The main vehicle of transmission of Salmonella is ……(one word, small letters)
Chicken
61
Food intoxications are often characterized by
very rapid onset compared | to food infections (e.g., minutes or hours vs. days or even weeks).
62
Botulism is caused by
is caused by the bacterial species Clostridium botulinum , which produces a powerful neurotoxin
63
Botulism is very rare by usually __
Lethal
64
Clostridium botulinum is an (conditions and food)
obligate anaerobe and the key organism of | concern in canning of low acid foods
65
What is the set mark between low-acid and high-acid foods and why
acid foods is pH 4.6 because spores of C. botulinum are incapable of germinating (i.e., of being reactivated to the toxin producing vegetative state) at a pH ≤ 4.6
66
Staphylococcal enterotoxins are
: Toxins produced by bacteria belonging | to the genus Staphylococcus .
67
Main vehicle of transmission of Staphylococcal enterotoxins
: food contaminated by food handlers (skin)
68
Once Staphylococcal enterotoxins are produced in a food, they are not
destroyed by subsequent cooking
69
Enterotoxins only act on the
intestines so this form of food intoxication | is seldom serious.
70
Mycotoxins are, by definition, toxins produced by
Molds
71
For example, the mold Aspergillus flavus in moldy | grain/cereals/peanuts produces
aflatoxin (a hepatotoxin).
72
Acute aflatoxin toxicity resulting in
liver failure and death occurs in animals but not in humans. In humans , aflatoxins are potent liver carcinogens : chronic exposure increases risk of liver cancer.
73
how many serotypes of e.coli are known
700
74
What can cause enteric infection and produce | toxins that can cause lysis of red blood cells.
When Shiga toxin producing E. coli (STEC) strains (such as O157:H7) colonize the intestinal tract
75
5-10% of people infected with STEC develop
hemolytic uremic syndrome , which can lead to kidney failure, permanent kidney damage, or death
76
infection with E. coli O 157 :H 7 was originally called
Hamburger disease
77
What food are particularly hazardous to e.coli
Unpasteurized milk and raw milk cheeses as well as raw meat particularly hazardous but no food that is served raw is exempt.
78
Viruses are not ___but they can be ___
spoilage organisms | pathogenic.
79
Viruses are ___ than bacteria
Smaller
80
What are noroviruses
(such as Norwalk virus) are considered to be responsible for ~50% of all outbreaks of foodborne illness in North America: they are very easily transmissible through food and water, as well as from person to person. Infection with noroviruses is extremely common but seldom a serious health problem.
81
What other viruses can be transmitted via food and water
Hepatitis A and polio
82
The second leading cause of death from foodborne illness (between salmonellosis and listeriosis) is
toxoplasmosis , a disease associated | with the protozoan parasite Toxoplasma gondii
83
Describe T.gondii
is a single celled eukaryotic organism that can survive outside a host in a dormant form ( cysts ) or as eggs (oocysts) for lengthy periods.  T. gondii can be transmitted as cysts in contaminated food and water (as well as by other routes) and infects all warm blooded animals,* including a large proportion of humans.
84
Who are special hosts for T.gondii
Cats
85
Protozoan parasited mainly occurs by
undercooked meat | (particularly, pork, lamb, and
86
Toxoplasmosis is (severity)
Most infected people are never aware that they are playing host to T. gondii  However, toxoplasmosis can be a very serious disease for those having weakened immune systems and infants (parasite may be transmitted during pregnancy).
87
Amoebic dysentery is caused by
food contaminated with the cysts of a protozoan parasite ( Entamoeba histolytica
88
Trichinosis nematodes are worms of the genus
Macroorganisms are worms of the genus Trichinella that cause the disease trichinosis
89
How can you get Trichinella nematodes and their specificity , and severity and transmission
. Their larvae may be ingested in undercooked meat , primarily pork, and develop into worms 3 mm long) in the intestines.  The female worms then produce more larvae that can end up in the bloodstream.  The severity of trichinosis depends on the number of larvae initially ingested. Trichinosis can be prevented by proper cooking , which destroys the larvae.  Trichinosis is mainly a problem in parts of the world where pigs are fed garbage or raw meat.
90
Anisakis are
is another genus of parasitic nematodes (i.e., worms) that can cause a foodborne illness ( anisakiasis ), specifically in foods of marine origin .
91
How anisakis are transmitted and how can be avoided
Their larvae may be ingested in raw (or lightly pickled/salted) saltwater fish as well as raw shellfish and can cause very severe intestinal symptoms.  Anisakiasis is very effectively prevented by freezing of marine products that are to be consumed raw,* which destroys the larvae.  * Blast frozen to 35 C or below for 15 hours or regularly frozen to 20 C or below for 7 days
92
However, even when larvae of anisakis are destroyed by freezing they can trigger ___
allergic response in some individuals.
93
Food stability of milk at room temperature
1 day
94
Food stability of meat/fish at room temperature
1-2 days
95
Food stability of leafy vegetables at room temperature
1-2 days
96
Food stability of fruits at room temperature
1-7 days
97
Food stability of root crops at room temperature
7-20 days
98
Food stability of dried seeds,real smoked meat and dried fruits at room temperature
more than a year
99
The basic job of food scientists and the food industry is to ___
protect food | from spoilage and the public from related health hazards
100
Food processing/preservation is effectively a means of buying time,
Food processing/preservation is effectively a means of buying time, thereby minimizing food losses and ensuring food security
101
With time what happens even to processed foods
very slow chemical reactions will manifest themselves as changes in color, flavor and/or texture as well as loss of nutrients
102
means by | which foods can be preserved:
Cold treatment : Growth of microorganisms and deteriorative chemical reactions are slowed down (refrigeration) or halted (freezing).  Drying/concentration : These processes preserve food by reducing water activity to prevent microbial growth  Heat treatment : Various types of thermal processes are employed to destroy microorganisms (canning, pasteurization) or inactivate enzymes (  Newer processes include ohmic heating , microwave processing , and high pressure processing .
103
Supplemental or Ancillary Means of Preservation
 pH reduction  Sugar/salt  Sugar and salt decrease water activity and draw water out of microbial cells via osmotic pressure Food additives  Sodium benzoate is one of a few permitted antimicrobial additives.  Antioxidants protect food components that are susceptible to oxidation.  Smoke (rarely used  Food is preserved by formaldehyde/pyrolysis products in wood smoke as well as heat and dehydration
104
How modification of atmospheres work
Controlled atmosphere storage (CAS) and modified atmosphere packaging (MAP) replace air by N 2 /CO 2 mixtures
105
Molds can’t grow on jams due to high concentration of sugar | and to the presence of acid in the fruit.
False

Introduction to food science (12 decks)

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