-capable of self-replication

-Size: ~1

- 10m in length, typically requires a microscope to visualize

(a)  

greek roots: mikros (small) + bios (life) + logia (study)

(a)  

-Monera

-Protista

-Fungi

-Plantae

-Animalia

(a)  

non- living, infective agents that require living cells for replication

(a)  

infectious proteins

(a)  

-Eukaryotes

-cells which possess a nucleus and organelles

-Prokarotes- cells which do not possess a nucleus

(a)  

-Fungi --Molds --Yeasts

-Protozoa- Animal Like Protists

-Toxic Algae--Dinoflagellate Algae--Cyanobacteria - Blue green algae

-Bacteria

(a)  

-Bacillus subtilis— Risk Group 1

-Salmonella enterica serovar

- Typhimurium - Risk Group 2

(a)  

-largest and most important group of microorganisms in food microbiology

-Most abundant group of organisms

- total numbers (viruses may be more abundant )

-Fastest growth rates-Simplest in structure and variety

(a)  

-Penicillium chrysogenum

-Aspergillus niger

(a)  

-Multicellular

-Polymorphic - variety of shapes/structures

-Single and Multi-cellular forms based on life stage

-Filamentous growth on surfaces

-Can be partially differentiated/identified using a microscope

(a)  

Molds are _______ growing while Bacteria is _______ growing

(a)  

-Saccharomyces cerevisiae

-Brettanomyces lambicus

(a)  

-Unicellular-Growth by budding

-Planktonic growth in submerged or semi-solid state environments

-Must be differentiated based on metabolic characteristics/growth habits

(a)  

is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site.

(a)  

-Cryptosporidium parvum

-Giardia lamblia

(a)  

-Small, single-celled, "animal-like" microorganisms

-Complex life-cycles

(a)  

-Gonyaulax catenella

-Alexandrium catenella

-Anabeana nostoc

(a)  

-Single-celled

-Algae - imprecise term that includes unicellular organisms such as dinoflagellate protozoa, cyanobacteria (bluegreen algae), and large plants including kelp

-Produce neurotoxins which can accumulate in shellfish - paralytic shellfish poisoning and similar syndromes

(a)  

What microorganism is hard to characterize because it could be parts of different micros based on what it looks like? Ex. Platypus

(a)  

-Rotavirus

-Norovirus

-Hepatitis

(a)  

-Obligate intracellular parasites - unable to replicate outside of a living cell

-Very small in size - 20-500 nm (0.22 um filter)

(a)  

-Broad classifications based on significance of microorganisms in food safety/spoilage/or diagnostic separation

-Useful as indicators of microbial hygiene, microbial food safety, microbial contamination

-Commonly used for "basic" microbial analysis of food

(a)  

-Provides general information on the total microorganisms present in a specimen

-Medium provides very little discriminatory power

(a)  

what you want to grow can be manipulated by temp, humidity, etc

(a)  

can help define what microbe it is

(a)  

-Gram-negative

-Rod-shaped

-Non-spore forming

-Facultative anaerobic

-Bile resistant

-Catalase positive

-Oxidase-negative

-Nitrate-reducing

-Enteric (intestinal)

(a)  

-Escherichia

-Klebsiella

-Salmonella

-Serratia

-Shigella

-Erwinia

(a)  

groups of organisms used as a proxy for specific microorganisms of concern to save time/money - "screening method"

(a)  

(a)   Family bacteria widely used as an indicator microorganisms - Colony count takes 24 hours on a nonselective medium

members of the enterobacteraceae that grow on selective media used as an indicator organism for water, food, food processing equipment.

(a)  

used as an indicator for fecal contamination

(a)  

-Enterobacteriaceae

-Grow on coliform media

-Ferment lactose

-Fecal coliforms--Escherichia coli--Enterobacter aerogenes

(a)  

-microorganisms that grow in cool, most, low-acid environments.

-Primarily spoilage microorganisms that produce slime and off-odors

(a)  

-Pseudomonas

-Acinetobactera

-Shewanella

(a)  

-Gram-positive-Rods or Cocci-Non-spore forming-Acid tolerant-Generally Recognized as Safe (GRAS)-Fermentation-Spoilage

(a)  

-Lactococcus

-Lactobacillus

-Leuconostoc

-Pediococcus

(a)  

- Lactobacillus, Lactococcus, Pediococcus, etc.

-Gram-positive, Lactic Acid producing bacteria.

-Important in fermentations and in spoilage

(a)  

-Widely spread

-Slow growth compared to bacteria

-Less fastidious-Harsher conditions

-High Salt

-High Sugar

-Dry

(a)  

-Semi-perishable foods

-Yeasts and Molds

-Spoilage microorganisms, which grow more slowly than bacteria.

(a)  

-Coccus

-Rods

-Spirillum

(a)  

-cylindrical bacterial cells; also called bacillus (plural bacilli)

-Examples: Escherichia coli, Bacillus cereus

-Arrangements: Chains or bifurcated

(a)  

-PROTISTA

-Protespherical or ovoid shaped bacterial cells; plural cocci

-Examples: Staphylococcus aureus, streptococcus thermophilus

-Arrangement: Chains or Cluster

(a)  

-curved/twisted/spiral shaped rods

-Examples: Campylobacter jejuni, Helicobacter pylori

(a)  

- structure is specific to function/purpose and the way It behaves in an environment

-The shape of a bacterium can provide us clues as to its physiology

(a)  

-Spirochetes

-Appendaged/Budding bacteria

-Filamentous Bacteria

-Segmented Filamentous Bacteria

-Candidatus Savagella

(a)  

tightly coiled bacteria

Example: Leptospira interrogans

(a)  

They look mostly straight spaghetti noodles

(a)  

Example: Caulobacter cresentus

(looks like a bean that has started to sprout)

(a)  

Example: Candidatus Savagella

(a)  

the permeability barrier of the cell, separating the cytoplasm from the environment

(a)  

-Phospholipid Bilayer

-Membrane proteins-Integral membrane proteins

-Peripheral membrane proteins

(a)  

-Permeability barrier - serves as a barrier to the influx and efflux-Transport proteins - "transporters" allow for the control of specific compounds in and out of the cell-Protein anchor - surface proteins are embedded in or covalently attached to cytoplasmic membrane constituents-Energy conservation - chemical gradient across the membrane can be harnessed to generate ATP

(a)  

Which Parts of the cytoplasmic membrane are hydrophobic & hydrophilic?

(a)  

peptidoglycan layer surrounding the cell that provides structural rigidity to the cell and protection against osmotic pressure

(a)  

-polysaccharide composed of alternating repeats of N-acetylglucosamine and N-acetylmuramic acid arranged in adjacent layers and cross-linked by short peptides-peptide: amino acids-glycan: polysaccharide-lysozyme: peptidoglycan degrading enzyme, present in tears, saliva, egg albumin

(a)  

differential staining procedure which stains bacterial either purple (Gram-positive) or pink (Gram-negative) based on thickness/amount of peptidoglycan in the cell wall

(a)  

a bacterial cell whose cell wall consists chiefly of peptidoglycan (multiple sheets/layers); it lacks the outer membrane of Gram-negative cells

(a)  

-teichoic acid: a phosphorylated polyalcohol found in the cell wall of some Gram-positive bacteria-lipotechoic acid: similar to teichoic acid but with an additional lipid portion

(a)  

a bacterial cell with a cell wall containing small amounts of peptidoglycan and an outer membrane containing lipopolysaccharide, lipoprotein, and other complex macromolecules

(a)  

a phospholipid- and polysaccharide-containing unit membrane that lies external to the peptidoglycan layer in cells of Gram-negative Bacteria

(a)  

gel-like region between the outer surface of the cytoplasmic membrane and the inner surface of the lipopolysaccharide layer of Gram-negative Bacteria

(a)  

a combination of lipid with polysaccharide and protein that forms the major portion of the outer membrane in Gram-negative Bacteria; endotoxin

-Important in toxicity of Gram-negatives in animal hosts inflammation.

(a)  

external coating of excreted polymeric substance (protein or polysaccharide) on the outside of the cell.

(a)  

layer arranged in a tight matrix that excludes india ink

Covalently linked to cell wall, not easily washed away

(a)  

looser arrangement that does not exclude other particles-Easily deformed/washed away

(a)  

Protection - Desiccation

Surface Adhesion - infection/biofilms

Virulence - immune evasion

(a)  

short thin proteinaceous filament (hair-like projection) extending from cell surface

-Typically many are arranged on a cell surface

(a)  

surface adherence, pellicle formation (liquid surface), virulence

(a)  

long thin proteinaceous filament (hair-like projection) extender from cell surface - one or a few

-Genetic exchange between cells

-Adherence to cells

-"twitching motility"

(a)  

Swimming motility - movement through a liquid medium

Swarming motility - movement across a surface

(a)  

long thin tail-like (whip-like) appendage capable of rotation and responsible for swimming motility

-Also serves as a virulence factor for pathogens including Salmonella and Campylobacter

(a)  

can be diagnostic for specific microorganisms

(a)  

having flagella emanating from one or both ends (poles)

(a)  

a "tuft" of flagella at one end

(a)  

lophotrichous flagella at both ends

-Example species: Vibrio fischeri, Bacillus brevis

(a)  

having flagella located in many places around the cell

-Example species: Escherichia, Salmonella

(a)  

A. Flagellar Filament

B. Flagellar Hook

1. L-Ring

2. P-Ring

3. MS-Ring

(a)  

differentiated structure produced by certain Gram-positive Bacteria

(a)  

Endosproes are highly resistant to:

(a)  

enables microbe to endure unfavorable growth conditions including desiccation, temperature extremes, nutrient depletion

(a)  

-Exosporium - thin layer of protein which is sometimes present

-Spore Coat - layer(s) of spore specific proteins, acts as a sieve to prevent large toxic molecules from getting inside.

-Cortex - peptidoglycan - left over from cell wall

-Core - contains essential cytoplasmic contents from vegetative cell

-dipicolinic acid (DPA) - protects DNA

(a)  

-Vegetative growth

-Sporulation

-Activation

-Germination

-Outgrowth

(a)  

"Vegetative cells" = actively growing cells

Cells actively grow and divide "normally"

(a)  

cell ceases vegetative growth and begins for form a spore (hours)

-External stimulus: nutrient limitation, extreme temperature changes, etc...

-Formation of spore structures and desiccation

(a)  

external stimulus that conditions and prepares spore for germination once conditions become favorable

-Spore will not germinate if conditions are favorable to vegetative growth unless activation has occurred - high, sub lethal temperature

(a)  

rapid process in which metabolic activity begins in the presence of chemical germinant - L-alanine or other amino acids.

(a)  

visible swilling of core due to water absorption and return to vegetative growth

(a)  

Moist Heat/Pressure - autoclaving/steam sterilization/canningDisinfection - alkylating and oxidizing agents - 10 % Solution of Household Bleach for 5 minutesTyndalization - germinate spores then rapidly kill themControl - keep conditions unfavorable to germination of the spores

(a)  

mathematical operation - expressed as b n , where b the base , is repeatedly multiplied n number of times.

(a)  

mathematical operation - inverse operation to exponentiation - meaning the logarithm of a number is the exponent to another fixed value, the base, must be raised to produce that number.

(a)  

Described in terms of population growth rather than individual cell growth

(a)  

increase in the number of cells

-Microbial cells have finite life span

-Species maintained by the continued growth of the population

(a)  

Cell division following enlargement of a cell to twice its size

(a)  

the time required for a population of microbial cells to double

(a)  

occurs when the growth rate of the value of a mathematical function is proportional to the function's current value

(a)  

growth of a microbial population in which cell numbers double within a specific time interval

(a)  

dynamics of growth for a population of bacterial cells

(a)  

period of time between the inoculation of a culture into fresh medium and start of growth

(a)  

period of time during which the population of cells is continuously doubling (cells at healthiest state)

(a)  

period of time during which no net increase or decrease on the number of cells

-Population growth rate during this phase is zero - cell death and cell doubling is in equilibrium (cryptic growth)

(a)  

period of time during which the population begins to die off

(a)  

physicochemical properties of a food; substrate limitations

-Growth Factors involving the physical, Chem and Substrate Application

(a)  

-Intrinsic Factor

-Extrinsic Factor

-Implicit Factors

-Processing Factors

(a)  

conditions of the storage environment; environmental limitations

(a)  

effect the growth of microorganisms by affecting intrinsic, extrinsic, (or implicit) factor

(a)  

a measure of how acidity (pH < 7) or alkaline (pH >7) a substance is

(a)  

Each microbe has a specific pH range in which it can grow (range of about (a)   pH units) with a defined optimum

Gram Negative Bacteria pH Ranges

(a)  

Gram Positive Bacteria pH Ranges

(a)  

Lactic Acid Bacteria pH Ranges

(a)  

Food-borne Yeasts pH Ranges

(a)  

Food Borne moulds pH Ranges

(a)  

ratio of the equilibrium vapor pressure of water in a food, P, to the vapor pressure of pure water, Po , at the same temperature

(a)  

able to grow in the presence of high concentrations of salt

(a)  

able to grow in the presence of high concentrations of non-ionic solutes - sugars

(a)  

able to grow on dry foods

(a)  

solute content reduces water activity of solutions

(a)  

Pure H2O has a aw = (a)   ; Dissolved solute in water - aw < 1.0

Staphylococcus aureus: only significant food pathogen able to grow below aw of (a)   , but is unable to produce staphylococcal toxin at that aW

Food

Acidity

Temperature

Time

Oxygen

Moisture

(a)  

-Potable/treated water during irrigation and processing-Moisture control before, during and after harvest-Pest control during production/storage-Prevent product damage-Hygienic practices/cold storage during further processing, food service, and retail

(a)  

-Population decreases

-Reduction in the number of viable microorganisms

-Microbial toxins already be present may not be inactivated

(a)  

-Population does not change

-No change in the number of viable microorganisms

-Microorganisms present may cause illness if consumed

-Cross contamination of other foods

(a)  

-Population increases

-Increase in the number of viable microorganisms

-Increased chance of spoilage/illness

(a)  

-Fermentation - production of a desirable product

-Food-borne Illness - infections, intoxication -(acute/chronic)

-Spoilage - loss of consumer acceptance

(a)  

process in which food deteriorates in some quality that it does not meet the expectation of a reasonable consumer

(a)  

Period of time between when food is prepared/packaged until it is becomes spoiled.

(a)  

Deterioration of organoleptic qualities:

(a)  

degradation of major molecules by enzymes produced by microorganisms or naturally present in the food; macronutrients

(a)  

enzymatic hydrolysis of carbohydrates by carbohydrate hydrolases (carbohydrases)

(a)  

breakdown of protein by proteases-Spoilage products: nitrogen and sulfur containing compounds: NH3, H2 S-Off-odors/flavors tend to be putrid; resembling old cabbage, rotten eggs-Microorganisms: anaerobes

(a)  

breakdown of triglycerides by lipolytic enzymes-Spoilage products: free fatty acids-Off-odors/flavors tend to be pungent, mousy, rancid-Microorganisms: wide range of yeasts, molds, bacteria

(a)  

enzymatic breakdown of cellulose, pectin, or collagen-Caused by carbohydrate (polysaccharide) hydrolysis and proteolysis-Changes to the food structure/texture

(a)  

non-enzymatic-Stale Bread - changes in gluten structure and degelatinizing of starch-Rancid butter/mayonnaise - oxidation of lipids-Wilting - loss/movement of water-Freezer burn

(a)  

Bacteria > Yeast/Molds

Gram-Negative Bacteria > Gram-Positive Bacteria

Aerobes > Anaerobes

(a)  

Refrigeration - Psychrotrohps > Mesophiles

Reduced aw - Gram-positive > Gram-negatives

(a)  

salt, sugar, and drying (aw); acid (pH);

(a)  

modified atmospheric packaging (gaseous atmosphere)

(a)  

Gram-negatives grow (a)   than Gram-positives in the same food when unpreserved

Gram-positives are typically (more/less) resistant to most preservations methods than Gram-negatives

(a)  

_________ _____ _________ predominate when conditions drop below minimum thresholds for Gram-positive and Gram Negative Bacteria

(a)  

-Dried/Low aw foods: grains and nuts (naturally dried on the crop); dried milk powder

-Acid Preserved Foods: fermented pickles, soft-drinks

-Chemically Preserved Foods: benzoic/sorbic acid

(a)  

-Algae: paralytic shellfish poisoning-Bacterial Pathogens: Includes the bacteria and/or toxins produced by the bacteria-Mold Toxins: Aflatoxin, Ochratoxin-Parasites: Protozoa (e.g., Eimeria spp.) ; Helminths (e.g., Trichinella spp.)-Infectious particles: Viruses (e.g., norovirus, rotavirus); Prions (e.g., Bovine spongiform encephalopathy, Creutzfeldt-Jakob Disease

(a)  

Agents not associated with disease in healthy human adults

Not harmful to us

(a)  

Agents associated with human disease that is rarely serious and for which preventive or therapeutic interventions are often available

-Pose a moderate health hazard

(a)  

Agents associated with serious or lethal human disease for which preventive or therapeutic interventions may available

-High individual risk, Low community risk

(a)  

Agents likely to cause serious or lethal human disease for which preventive or therapeutic interventions are not usually available

"We got a 2319!"

(a)  

Mold = Multicellular

Yeast = Single Cellular

(a)  

Organisms favor slightly more (a)   conditions