Food Micro Final


Terms in this set (...)

Slow method of pastuerization temp and time
145 (63) for 30 min
Faster method of pastuerization
161 (72) for 15 sec
Sterilization temp range and time
293 (145) to 302 (150) for 1 to 2 min
Heat kills microorganisms by ____
denaturing nucleic acids, proteins, enzymes
In heat injury MO cells will show a loss of
Heat influence on enveloped viruses
lose receptor sites
Heat impact on microflora
disrupt carbohydrate bonds weakening membrane, make phospholipids become fluid and leaky, disrupts membrane transport
Temp classification that causes structural disruption of spore coat
Temp classification that causes damage to spore structures destined to become membrane/wall.
Temp classification that causes inability to use water during germination
Fats, carbs, and proteins due what
increase heat resistance
The time value that corresponds to the death of 1 log (90%) at a constant given temp
d value
Minimum heat treatment to reduce the probability of survival of C. botulinum cells to 10 to 12.
12 D Concept
The change in temperature necessary to bring about a 10-fold (1log) change in the D value
Z value
1962 Code stipulates that potentially hazardous foods should be held below ___ 0r...
45 (7.2)
1962 Code stipulates that potentially hazardous foods should beheld bolow... or above ____
140 (60)
1993 Code lowered the keep below temp to..
41 (5)
is expressed to the time (min) necessary to completely
destroy a specific number of microbial spores or cells at a reference temperature
F value
Thermal process validation Phase 1 is
Process/ Product Review
Thermal process validation Phase 2 is
Microbial Kinetics (TDT)
Thermal process validation Phase 3 is
In-Process Validation
Pathogenic organism(s) of significance in a given food product
Target organism
Non-pathogenic organism which mimics process resistance of target organism and is suitable for use in validation work
Surrogate Organism
Process step which results in
sufficient destruction of the target organism
kill step
Mathematical correlation between the destruction of surrogate and target organisms.
Kill ratio
Measure of process's ability to destroy the target organism, normally expressed as 'log reduction' for the target organism
Process lethality
a common surrogate used for Salmonella
for the evaluation of thermal processes applied to low moisture foods
Enterococcus faecium
Foods with a content are particularly good candidates for HPP technology
high acid
HPP primary site of damage
cytoplasmic membrane, ribosomes are denatured, ribosomes disassociated,
Biochemical HPP effects
inactivation of key enzymes,
Cellular component more resistant to HPP
nucleic acids
Pressure region for deactivation of vegetative cells
400 to 600 MPa
Spores can survive pressures exceeding
1000 MPa
Spore inactivation by a number of high pressure cycles, with no previous germination, is because of changes in
permeability and disruption of the wall
by combining pressures from 50 to 250 MPa with temperatures from 40°C you can
induce spore germination
Two limitations of HPP
Food must contain water and not have internal air pockets
Potential pitfall of HPP
Enzyme activity may increase
Significant product limitation of HPP
cannot be used to make shelf-stable versions of
low-acid products such as vegetables, milk, or soups
A 215-liter batch system has the
capacity to produce about __ pounds of food per yr
10 million
__ processing is another non-thermal
method of food preservation that uses short
bursts of electricity for microbial inactivation
Pulsed Electric Field (PEF)
PEF is often used to process ____
liquid and semi liquid
PEF involves treating foods placed between electrodes by high voltage pulses in the order of
20 to 80 Kv/cm for a couple microseconds
In PEF ___ are the least efficient for microbial inactivation.
Oscillatory pulses
In PEF ___ pulses are more energy and lethally efficient than exponential decaying pulses
Square wave
_____pulses are more lethal than_____ pulses
Bipolar monopolar
Gram____ are more resistant to PEF than
those that are gram____
positive negative
In general, ___ phase cells are more
sensitive to stress than ____phase cells
logarithmic, lag and stationary
Advantage of PEF
Foods retain the fresh like flavor, aroma, appearance, nutritional value and offer a great shelf life.
Limitations of PEF
Efficacy of spore inactivation by PEF with other hurdles is not clear

restricted to food products with no air bubbles and low conductivity
PEF pasteurization kills microorganisms and inactivates some enzymes and, unless the product is acidic, it requires____
PEF example foods
juices, milk, yogurt, soups, and liquid eggs
HPP example foods
fruit smoothies, guacamole, ready meals with meat and vegetables, oysters, ham, chicken strips
Two ways a food borne illness outbreak stops
Cases just stop with no confirmed cause, or a recall is issued or contamination contained
Top five pathogens contributing to domestically acquired foodborne illnesses
Norovirus, Salmonella, C. perfringens, Campylobacter spp., Staphylococcus aureus
Estimated number of domestically acquired food borne illnesses resulting in hospitalization.
L. monocytogenes has __ serotypes
L. monocytogenes is what kind of pathogen residing where
Intracellular cytosol
L. monocytogenes is gram ___ is _____ , salt classification
positive, non-sporulating, halophilic
L. monocytogenes is (respiratory type), (temperature temperament,
Micro-aerobic, Psychrotroph 0 - 45° C, freeze tolerant,
S. aureus, gram and morphology, temp range, water activity
Gram positive cocci,
S. aureus temp range
mesophile, does not grow at refrigeration temperatures
S. aureus water activity, salt
grows at low water activity, survives very low water activity ~ 0.86 or 20% NaCl
S. aureus virulence factor (heat)
thermostable at 100 C for 30 min
S. aureus virulence factors - major toxins
S. aureus virulence factors - minor toxins
G,H,I, J
S. aureus virulence factors - toxin causing toxic shock
S. aureus infectious dose
20 ng
C. perfringens gram and morphology
Positive rods
C. perfringens respiratory type
C. perfringens spore type
C. perfringens temp
C. perfringens Heat treatment tolerance veg cells
D 56.8C/48.3 min
C. perfringens virulence factors
C. perfringens Heat treatment tolerance endospores
differ in resistance to heat - D 100C 0.75 to 38 min
L. monocytogenes virulence factors
ingestion of live cells necessary, infectious dose unclear - Can be lower than 100 CFU.
L. monocytogenes virulence factors - incubation
very long
L. monocytogenes virulence factors - invasive
All invasive strains produce the invasin internalin
L. monocytogenes virulence factors - toxin production
All virulent strains produce listeriolysin O - pore formation and invasion of gut
C. perfringens disease mechanism
replication of bacteria in intestinal tract
C. perfringens toxin classification
based on ability to produce endotoxins, 5 types, A-E
C. perfringens type A food poisoning
enterotoxin occurs together with that of sporulation, high infectious dose
C. perfringens type C
Necrotic enteritis
C. botulinum, gram and morphology
positive rod
C. botulinum respiration Spore-
forming rod
C. botulinum, spores?
C. botulinum virulence factors - number of types/basis
Seven types, A-G based on serological specificity of their toxins.
Human botulism associated with types
A, B, E, and rarely F
C. botulinum virulence factors - disease initiation
preformed exotoxin in food; botulinal neurotoxin (BoNT)
C. botulinum virulence factors - toxin
BoNT are the most toxic substances known
Human LD50 is about 1.0ng/kg
C. botulinum virulence factors - toxin requirements
toxic only after released by cell lysis and cleavage by a proteinase activates
Bacillus cereus gram and morph
positive rods
Bacillus cereus spores?
Bacillus cereus respiration
Bacillus cereus cycle
parasitic like endosymbiotic life cycle with primary and secondary hosts
Bacillus cereus heat tolerance
veg killed, endospores survive heat
Bacillus cereus virulence factors - enterotoxins
2 multi unit, 1 monomeric
Bacillus cereus virulence factors - toxins
emetic toxin enzymatically produced not ribosomally
1994 Ice cream out break of what, how many people
salmonellosis 224,000 USA
1988 clams outbreak of what, how many people
Hep A, 300,000 China
Salmonella - two species
enterica, bongori
Most common Salmonella serotypes worldwide
Salmonella enterica serotypes Enteritidis and Typhimurium
Primary source of serovar Enteritidis
Emerging Salmonella reservoir
soil - taken up through plant roots into produce
Other salmonella sources
beef, pork, farmed fish and shellfish
Salmonella temp ranges
very adaptable, depends on strain
Salmonella pH range
Grow between pH 4.5 - 9.5, wide optimum 6.5 -
Salmonella gram and morph
negative rods
Campylobacter - numbers/kinds
Two genera
Campylobacter - 18 species
Arcobacter - 4 species
Campylobacter - stain and morph
Gram negative, small, curved or spiral rods
Campylobacter respiration
Campylobacter temp range
mesophilic, growth optimum 37 to 41,survive well at 4°C, survive freezing poorly
Campylobacter - enviromental tolerances
Sensitive to drying, low pH, high O2, heat
Campylobacter - reservoirs
Warm-blooded animals only known reservoir, poultry, pigs, cattle, various others
Campylobacter - vehicles of infection
Vegetables w/soils, seafood from farms, water, unpasteurized milk
Campylobacters are most common world wide cause of
bacterial gastroenteritis
Campylobacters - for every reported case there are ___ suspected others
Campylobacters - most infections come from __ ___
consumption and handling of poultry, or through raw milk
Virulent E. coli have acquired
pathogenecity islands
E. coli typed by antigen type
O - somatic antigens, H - flagellar antigens
E. coli EPEC
Enteropathogenic humans primary reservoir
E. coli ETEC
E. coli EIEC
E. coli EHEC
E. coli Infective dose is
10 -100 CFU
Food related Hepatitis A is responsible for ____ of all hepatitis cases
Hepatitis A viral family and genome characteristics
Picornaviridae, ssRNA
Hepatitis A Infectious dose
unknown, probably 10 to 100
Hepatitis E is also known as
enterically transmitted non-A non-B hepatitis
Which type of Hep has not been specifically isolated from food
Which type is most associated with shellfish, and salads
Which type has a vaccine in development
Which type more common in adults than children
Noroviruses also known as
SRSV small, round structural viruses
Noroviruses family
Estimated cases of Noroviruses annually
50 million
Most common reservoir of Noroviruses
Noroviruses associated with
shellfish, salad, any food handled by an infected
Noroviruses infectious dose
as few as 18 particles
Noroviruses recommended detection method
Rotaviruses family
Rotaviruses structural characteristics
nonenveloped, dsRNA viruses
Rotavirus typing
groups (A-E) and subgroups on the basis of the antigenic specificity of the major virus structural protein VP6
Rotavirus types that infect humans, most common
A, B, C, A is most common
Rotavirus sources
cattle and pig intestines
Rotavirus are the major
non-bacterial diarrheal agent
Rotavirus known for causing
Traveler's diarrhea
Rotavirus infectious dose
10 to 100 particles
Rotavirus primary route of transmission
fecal - oral
Rotavirus worldwide burden (Children)
611,000 deaths under 5 yrs of age
Method of killing most rotaviruses
Exception to chlorination
Norwalk varieties have survived chlorination to 3.75 ppm
Vaccines are available for which one, noraviruses or rotaviruses?
Mycotoxins are secondary metabolites produced by
fungal hyphae during the end of exponential phase
General condition that favors mycotoxin production - Temperature
40 - 90 F, (4 - 32C)
General condition that favors mycotoxin production - Humidity
> 70%
General condition that favors mycotoxin production - Moisture
22-23% in grain
General condition that favors mycotoxin production - oxygen
Two categories of mycotoxin producing fungi
Before Harvest - field fungi, After harvest - storage fungi
First type of field fungi
Plant pathogens (Fusarium,
2nd type of field fungi
opportunists that grow on senescent or stressed plants (F. moniliforme),
3rd type of field fungi
fungi that start in the field but predispose commodity to post harvest contamination (penicillium and A. flavis)
3 factors associated with higher chance of mold growth and mycotoxin production
High field density, poor fertility, weed competition
Aflatoxin produced by what two primary species
Aspergillus flavus, A. parasiticus
Aflatoxin types and basis
B1, B2, G1, and G2 based on their fluorescence under UV light
__________is produced by all aflatoxin positive strains and is the most potent natural carcinogen known
Aflatoxin B1 (AFB1)
a hydroxylated product of AFB1 that appears as a metabolic product in milk, urine and feces of intoxicated animal
Aflatoxin toxicity acute or chronic
Aflatoxin toxicity most serious effects are
long term
Aflatoxin toxicity effects
acute liver damage, liver cirrhosis, tumor induction, teratogenic, immunosuppressive effects
Aflatoxin toxicity order
Control mycotoxins by keeping products below
.7 aw
4 other methods of controlling mycotoxins
binders, developing host resistance, use of biocontol agents, targeting regulatory genes in mycotoxin production.
3 distinct groups of parasites
flatworms, round worms, protozoa
host animals that harbor the mature adult worms
host animals that harbor the immature, larval forms
Through pigs as an intermediate host
Taenia solium
Through pigs as intermediate hosts and rats as transport hosts
Trichinella spiralis
Taenia solium, type?
Trichinella spiralis, Ascaris, type
Entamoeba histolytica Type?
Cryptosporidium Type?
Cyclospora Type?
Giardia Type?
Components of Kingdom Protist
algae, fungi, protozoa
___ is the common parasitic syndrome in humans
The common causes of Taeniasis
Taenia saginatus or T. solium
Disease causing roundworms of Roundworms primary importance in foods belong to phylum
Primary mode of roundworm transmission
eating raw or poorly cooked animal meat containing larvae
___ is primarily transmitted through pigs, while rats are primarily responsible for maintaining the endemicity of this infection.
Parasite control measures
All stages are killed by cooking food to 160. good husbandry practices, chlorination of water (oocysts still survive in there)
a document approved through consensus by a recognized (standardization) body that provides for repeated and common use, rules, guidelines or characteristics for products or related processes and production methods, with which compliance is not mandatory.
Four functions of a standard
Fitness for purpose,
Safety, health and environmental protection,
Variety control
Any procedure used, directly or indirectly to determine that relevant requirements in Technical Regulations or Standards are fulfilled.
Conformity Assessment
Conformity Assessment (CA) objective
One Audit - One Certificate, One Test - One Report
First party CA Carried out by
supplier organization
Second party CA Carried out by
Third party CA Carried out by
independent body
ISO 9001
Quality management systems
ISO 22,000
Food safety management systems
ISO 14,000
Environment management systems
ISO 17,025
General requirements for the competence of
calibration and testing laboratories
Specifies requirements for a food safety
management system where an organization in the
food chain needs to demonstrate its ability to
control food safety hazards in order to ensure that
food is safe at the time of human consumption
ISO 22,000
Accreditation is granted by National Accreditation
Bodies under International Laboratory Accreditation
Cooperation (ILAC)
• Specify the general requirements for the competence to carry out tests and/or calibrations, including sampling
• It covers testing and calibration performed using
• standard methods
• non-standard methods, and
• laboratory-developed methods
• Compliance with regulatory and safety requirements on
the operation of laboratories is not covered by
ISO 17025
created in 1963 by Food and Agriculture Organization (FAO) and World Health Organization (WHO) to develop food standards, guidelines and related texts such as codes of practice under the Joint FAO/WHO Food Standards Program
Codex Alimentarius Commission (CAC)
FSMA granted two new critical powers to the US FDA
Mandatory recall authority, power to suspend the
registration and operations
It was created in response to the Homeland Security Presidential Directive _____ that established food as a critical infrastructure for the U.S. post Sept 11, 2001
is a national network of public health and food
regulatory agency laboratories coordinated by the Centers for Disease Control and Prevention
The Foodborne Diseases Active Surveillance Network, or ______, has been tracking trends for infections
commonly transmitted through food since 1996
• It estimates the number of foodborne illnesses, monitors trends in incidence of specific foodborne illnesses over time, attributes illnesses to specific foods and settings, and disseminates this information.
stands for Foodborne Diseases Centers for
Outbreak Response Enhancement
The _____ tool is a web-based platform for searching
CDC's Foodborne Disease Outbreak Surveillance System database, ____provides access to national information and is intended to be used for limited descriptive summaries of outbreak data.