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Physiology of Lactation > Quiz 5 > Flashcards

Quiz 5 Flashcards

1
Q

Why is milk seldom used in other food products

A

High Concentration of water and water is difficult and expensive to move

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2
Q

Grade A Milk

A

95% of milk is grade A
Grades determined by the Pasteruized Milk Ordinence
Nearly impossible to find producers who will take lower than Grade A

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3
Q

PMO Temperature Requirements for Grade A

A

Raw: 7 degrees C or less within 2 hours of milking
Pasteurized: 7 degrees C or less and maintained

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4
Q

PMO Bacterial Limits for Grade A

A

Raw: 100,000 or 300,000 CFU/mL Standard Plate Count
Coliforms 10 CFU/mL

Pasteurized: 20,000 CFU/mL

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5
Q

PMO SCC for Grade A

A

750,000 cells/mL

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6
Q

PMO Drug Test for Grade A

A

NONE

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7
Q

PMO Phosphatase Test for Grade A Milk

A

Pasteurized: Phosphatase Negative. Indicates proper time and temperature pasteurization

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8
Q

Titrateable Acidity

A

0.16% max
Measure of the Acidic Compound in Milk
High if bacteria make lactic acid

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9
Q

Freezing Point

A

-0.530 Degrees Celcius
Addition of water to milk raises the freezing point
Prevents artificial increases in volume

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10
Q

Total Solids

A

Whole: 12-13%
Skim: 8.9-9.3%

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11
Q

Which two microorganisms must raw milk be negative for?

A

Listeria
Salmonella

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12
Q

Standard Plate Count Limit for Psychrotrophic Bacteria

A

10 CFU/mL

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13
Q

Milk Processing Sequence

A

Heat Exchanger
Centrifugal Separater
Automatic Fat Standardization Device
Homogenizer
Return to Heat Exchanger

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14
Q

Standardization

A

Purpose: to provide a consistent fat content for processed products
–Nonfat (skim): <.5% milkfat
-Lowfat: 1-2% milkfat
-Full fat: 3.25% milkfat
-Half & Half: 11% milkfat

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15
Q

Primary and Secondary purposes of pasteurization

A

Primary: destroy all pathogenic bacteria to prevent milk-borne illness. Originally, tubercle bacillus, causative organism for tuberculosis (TB)
Secondary: reduce all vegetative (spoilage) bacteria and denature enzymes to extend shelf-life of milk

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16
Q

What is the organism on which the thermal process for pasteurization is based?

A

Coxiella burnetti – heat resistant pathogen; more resistant than TB organism
Mycobacterium paratuberculosis - concern

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17
Q

What is the relationship between time and temperature
in thermal processing?

A

Higher temperature, shorter time for same lethality

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18
Q

Time and Temperature for batch and HTST of milk

A

Batch = 30 min at 62.7 Degrees Celcius
HTST = 15 seconds at 71.6 Degrees Celcius

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19
Q

What are some detrimental effects of heat processing fluid milk?

A

Adverse effects on appearance, taste, nutritional value
Proteins denatured at high temps
– Affects cheese production and yield
- Cooked flavor

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20
Q

Why is the temperature for pasteurizing high fat products higher than for fluid milk?

A

Fat is a poor heat conductor so it takes longer to
heat the product thoroughly

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21
Q

Why isn’t the phosphatase test used for acidified products? What is used instead?

A

Peroxidase test used for acidified products because peroxidase takes a higher temperature for inactivation; heat cultured products higher in order to denature whey proteins

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22
Q

What is the primary purpose of ultra pasteurization processing?

A

UP: Extended shelf-life (ESL), allows for longer distribution periods
UHT (aseptic): Processing protects the product from re-introduction of bacteria from the air, filled into sterile package

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23
Q

Sterilization

A

In-package thermal process that kills all vegetative bacteria and destroys spores

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24
Q

Results of Homogenization

A

Milkfat globule size decreased
# globules increased
Surface area increased
surface material changed

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25
Q

Process of Homogenization

A

Milk fat globules are forced through a narrow gap so they break into smaller globules that are stable in the emulsion
Small droplets will still want to aggregate but they are easily separated
Two-stage process

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26
Q

Why does mastitis matter?

A

Most economically impactful disease in dairy production due to its prevalence and impact

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27
Q

Causes of mastitis

A

Physical Force (Trauma)
Infectious Agents (Bacteria)

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28
Q

Pathogenesis of Mastitis

A

Colonization by pathogen
- adhesion to mammary epithelium
- expression of virulence factors
- production of toxins
Inflammatory Response of Cow
- increased vascular permeability
- leukocyte migration
- phagocytosis
Spontaneous Cure, Clinical Case, Subclinical Case

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29
Q

Costs of Mastitis

A

18.6 Million Dollars in Virginia
2 Billion Dollars in US (OLD NUMBERS)

23% Replacement Cost
6% Discarded
5% Treatment
66% Reduced Milk Production

30
Q

Milk Loss by SCS

A

Milk loss begins at SCS of 3 or SCC 72,000-141,999 at 1.5 pounds less per day
For every one increase in SCC there is a 1.5 pound increase in milk loss

31
Q

Inflamation

A
  • Inflammatio = set on fire
  • Response to injury
    ○ Inflammation is part of the healing response
    ○ Deliver defensive materials (cells and plasma proteins) to a site of injury
    - Role in repair and remodeling of tissue

Heat, Redness, Swelling, Pain, Loss of Function

32
Q

Signs of Mastitis at Milking

A

Clots in milk after stripping

33
Q

Susceptibility to Mastitis

A

Incidence of mastitis increases when defense mechanisms of the mammary gland are impaired.
○ The Transition Period - Reduces Immune function and increases susceptibility

34
Q

Factors Affecting New Infection Rates?

A

Management and Environment - 90%
Genetics - 10%

35
Q

Periods of Increased Susceptibility to Mastitis

A

Calving
Dry-Off
○ If there are pathogens in the mammary system, when we stop milking we are no longer flushing those out and they have the ability to grow in the mammary system

Transition Period

36
Q

Factors that Affect the Rate of Infection

A

Environment
Bacteria
Cow
Environment x Cow = Stress
Environment X Bacteria = Spread
Bacteria x Cow = Exposure

37
Q

Colonization of Mammary Gland by Pathogens

A

Once a pathogen enters the mammary gland it can grow faster than it can be controlled and the bacteria adhere to the mammary epithelial and colonize the mammary gland
Virulence factors improve the survivability of the pathogen in the mammary gland

38
Q

Inflammatory Response of the Cow

A

Increased vascular permeability to move more immune cells into the interstitial fluid and mammary gland
White blood cells engulf pathogens

39
Q

5 Point Plan of Mastitis Control

A

Proper maintenance/use of milking equipment
Teat Dips/Proper Milking Procedure
Treat Clinical Cases
Dry Cow Therapy
Cull

40
Q

Categories of Pathogens

A

Contagious
○ Spreads from animal to animal
○ Sometimes bacteria varieties are those which use the mammary system as a host
Opportunistic
○ Cause infection if they have the opportunity but live other places
Environmental
○ Found in the environment but may cause infection

41
Q

Contagious Pathogens

A

Spread from cow to cow during milking
§ Preventing cross contamination between infected and healthy cows
primary source is infected udders
transmission at milking
usually establish chronic subclinical mastitis

42
Q

Streptococcus agalactiae

A

CONTAGIOUS PATHOGEN
Gram positive cocci
Beta hemolytic
Capsule
Obligate pathogen of the udder
Problematic in the past but not seen often anymore

43
Q

Staphylococcus aureus

A

CONTAGIOUS PATHOGEN
Gram positive cocci
Sphere Shaped (cocci)
Grow in Clusters (Staphylo)
Colonize skin, nasal cavity, mucous membranes
Thrives on unhealthy skin
Multiple virulence factors
§ Help the organism be infective
§ Adhesin - ability to couple with the epithelial surface
§ Capsules, slime - factors that prevent access of IgG and Complement
§ Protein A - Bind antibodies in the wrong way
§ Coagulase - breaks fibrinogen
S. aureus is very difficult to control within the dairy industry
Can cause abscess and clot formation in the mammary system
If the clot blocks the mammary ducts there is regression of the lobe or lobule

44
Q

Corynebacterium bovis

A

Contagious Pathogen

45
Q

Opportunistic Pathogens

A

Coagulase Negative staphylococcus
Primary Source is on healthy teat skin and milker’s hands
Transmission is related ti bacterial load on teat ends
Common in heifers, often right after calving
Detected in ~25% of lactating cows
§ Rate changes with stage and number of lactation
About half of infections are persistent
§ Dependent on pathogen
§ Not easy to control
Readily eliminated with efficacious post milking teat dipping
Dry cow therapy eliminated most existing infections
New infections at calving respond to lactation therapy

46
Q

Environmental Pathogens

A

Primary source is the cow’s environment
Transmission of bacteria occurs between milkings
Incidence is higher in herds that control the contagious pathogens
§ Eliminating one pathogen creates the opportunity for other pathogens to infect the mammary system due to decreased competition
Coliforms
§ Present in the environment of all dairy cows
□ Gram Negative Rods
□ Differentiation
® MacConkey Agar
◊ Selective for gram negative and Lactose Fermentation = pink colonies

47
Q

Examples of Opportunistic Pathogens

A

Staphylococcus chromogenes
Staphylococcus hyicus
Staphylococcus warneri
Staphylococcus epidermidis
Staphylococcus simulans
Staphylococcus xylosus
Staphylococcus sciuri

48
Q

Examples of Environmental Pahogens

A

Escherichia coli
Klebsiella species
Enterobacter species
Streptococcus uberis
Streptococcus dysgalactiae

49
Q

Pathogenesis of E. Coli

A

The immune system is responding to the toxins, not necessarily the bacteria
In severe coliform infections, the infection can take over the whole body

50
Q

Lipopolysaccharide

A

Part of the cell wall of most gram negative bacteria
Consists of three components
- O Side Chain
- Inner Core
- Lipid A

51
Q

Therapy of Coliform Mastitis

A

Typically controlled by the cow herself
Treatment Considerations
○ “Stripping out” mild clinical cases of coliform mastitis is preferred
○ Most coliform infections are cleared by natural defenses of the host
○ Supportive therapy is important
§ For when the infection is systemic
§ IV Fluids
§ Fever = Systemic Response
○ Vaccine
§ Does not prevent the infection but reduces the effect of the toxin

52
Q

Trueperella pyogenes

A

Opportunistic (soil pathogen)
Bad infusion practices

53
Q

Nocardia species

A

◦ Opportunistic (soil pathogen)
◦ Bad infusion practices

54
Q

Prototheca species

A

Colorless algae (water/soil pathogen)
◦ Bad infusion practices

55
Q

Yeast and molds

A

Bad infusion practices
Bacillus spp.
Bad infusion practices

56
Q

Psuedomonas aeruginosa

A

Environmental
Water
Drop hoses

57
Q

Proteus spp.

A

Environmental
On blood agar, it will swarm across the plate

58
Q

Mycoplasma species

A

Contagious
Outbreak preceded by respiratory disease

59
Q

California Mastitis Test

A

Used for Detection and Diagnosis of Mastitis
Measures nuclear DNA
Equal volume milk and CMT solution
Mix by rotating in circular motion
Determine gelling by rocking back and forth
Degree of thickness will determine degree of inflammation

60
Q

Somatic Cell Counts - Why?

A

Increases in milk to combat bacteria

61
Q

Why should you culture individual cow’s milk

A

Identifies specific pathogens
Therapy recommendations
Culling decisions

62
Q

When should milk cultures be done?

A

Before drying off
At calving
Clinical symptoms
High SCC

63
Q

Bacteriostatic

A

Inhibit Growth

64
Q

Bactericidal

A

Kill

65
Q

Discovery of Penicillin

A

Alexander Flemming
- Penicillium notatum mold inhibited the S. aureus growth on his culture
Howard Florey and Ernest Chain
- Mass production of penicillin for human use

66
Q

Mode of Action of Antibiotics

A

Inhibition of Cell Wall Synthesis
Inhibition of Protein Synthesis
Inhibition of Synthesis of Essential Metabolites
Injury to Plasma Membrane
Inhibition of Neucleic Acid Replication and Transcription

67
Q

Sources of Resistance

A

Nosocomical Infections
Animal Treatments and Feed Additives
Inappropriate Treatment Regimes
Premature use of Last Resort Drug
Failure to confirm culture and susceptibility

68
Q

Why are antibiotic residues in milk a bad thing?

A

Many consumers have allergies to antibiotics

69
Q

National Mastitis Council Mastitis Prevention

A

Pre and Post Milking Teat Disinfection
Blanket Dry Cow Therapy
Proper Treatment of Clinical Cases
Regular Milking System Analysis and Maintenance
Cull Chronically Infected Cows
Monitor High SCC

70
Q

Common Contagious Pathogens

A

Staphylococcus aureus
Streptococcus agalactiae
Prototheca
C. bovis

71
Q

Common Environmental Pathogens

A

Coliforms
Streptococcus dysgalactiae
Streptocuccus uberis
Environmental Strepts

Physiology of Lactation (8 decks)

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