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cow sheep goat buffalo horse human
Water %
Dry mat
(%)
87,5
80,7
87
82
89
87,6
12,5
19,3
13
18
11
12,4
Fat
(%)
3,7
8
4
7,9
1,9
4
Proteins
(%)
Lactose
(%)
Minelars
(%)
3,3
5,6
3,6
4,5
2,5
1,2
4,7
4,8
4,5
4,8
6,3
7
0,8
0,9
0,9
0,8
0,3
0,2

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Organised into globules (1-10 μm ) having membranes of phospholipid-protein complexes
200 kinds of fatty acids
Fatty acids of saturated (palmitic, myristic, stearic, butyric, etc.), mono- and poly unsaturated (oleic, palmitoleic, linoleic, linolenic, etc.)
Holstein:3.3-3.4%, Jersey: 4.5-4.6 %

cow sheep goat buffalo pig horse dog human
Casein
%
40
45
50
40
82
80
80
85
Whey protein
%
60
55
50
60
18
20
20
15

 Caseins ( α
1
, α
2
, ß, κ
)
 Colloidal micelles (0.12 μm)
 Submicelles are bound together by calcium phosphate and, organised into spherical particles of micelles (20-300 nm )(
κ
-casein at the surface of micelles)

Rennin or <pH 4.7→ coagulation

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Remaining in milk after precipitating casein (include proteose-peptones
Albumin

ß and α –lactoglobulin
 Serum albumin
Globulin
 Immunoglobulins
 Lactoferrin
α and ß lactoglobulins (synthesis in mammary gland),
Serum albumin and immunoglobulins are from blood

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Lipase
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In fresh milk: inactive
In cream: concentrated
Inactivation at 70 °C, pH optimum: 7,6-7,8
Amylase
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In fresh milk: low
During storage activity ↓↓→ detection of freshness
52-56 °C, 30 min
Protease
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Only raw milk, longer storage at 37-42 °C temperature.
Pastuerised milk→ putrid taste
Clostridium, Achromobacter spp. →cheese production

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 peroxidase
 75 °C 2,5 min, 85 °C 1-2 s →flash pasteurization alkaline phosphatase
 62 °C 30 min, 72 °C 15 s → pasteurization xanthine oxydase

Cow milk ↑, human ↓ ( Schärdinger reaction)
Catalase

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Activity ↓
Mastitis: activity ↑

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Carbohydrates
 Lactose

4.7-4.8 % (mastitis →↓)
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80 °C→lactocaramell (taste of boiled milk)
Lactobacilli → lactic acid
Minerals, micro-macroelements
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0.7-0.9 %
Mastistis: Na, Cl →↓, K, Ca, Mg, P→↑

Phosphate
Citrate
K
Ca
Cl
Na
Mg minerals g/l
2,1
2
1,4
1,2
1
0,5
0,1
I
Zn
Fe
F
Cu
Mn
Se microelements
μg/l
4000
400
200
100
40
30
10

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Trace elements
 1 μg – 5 mg/litre
Vitamins
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A, B
12
, E, K, D
3
, C
Thiamine, riboflavin, nicotinic acid, panthothenic acid, pyridoxine, biotin, folic acid
Concentration is depending on species, age, stage of lactation, nutrition, environment, etc.
Sensitivity to light, air, metals, acid, etc.

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Polydisperse structure of milk
Milk as polydisperse system consits of:
 Dispersing medium of water
 Emulsified fat
 Collodial proteins

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Somatic cell
≤ 400 00

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70-80 % tissue origin
Blood origin (granulocyte, lymphocyte, monocyte)
Microorganisms

≤10 4

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Freezing point: -0.5 °C
Colour
 Normal: bluish-white (golden-yellow), depending on breed, feed, lactation period, etc. (white: fat globules, collodial components; bluish: after removing fat; yellow: carotene)
Taste
 Normally, slightly sweet, pleasent (lactose and chlorine)
 Fat and protein give the body to the flavour
Consistency (substance) of milk
 Normal milk is a watery liquid

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Milk
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High aw, neutral pH,
Rich in nutritional materials
Antimicrobial substances
 Lactoferrin

Fe binding, bacteristatic effect
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Against Gr- bacteria
Lactoperoxidase

Against Gr- bacteria
Lysosyme

Muramidase

Against Gr+ bacteria

Source
Cell/ml
Healthy udder 100-500
Subclinical mastitis 10 4 -10 5
Microbes
Micrococcus, Staphylococcus, Streptococcus,
Lactobacilli
Staphylococcus, Streptococcus
Skin of the udder 10 2 -10 4
Micrococcus, Staphylococcus, Streptococcus,
Lactobacilli, coliforms, pathogens
Air of stable
Milking machine, tubes
10 2
10 3 -10 6
Aerobe spores
G-, Pseudomonas, eneterobacteria

Micro-organism
Micrococcus, Staphylococcus
Streptococcus,, Lactococcus
Microbacterium, Lactobacillus
Bacillus, Clostridium
Pseudomonas, E. coli, Alcaligenes,
Acinetobacter
Yeast, mould
Occurence (%)
30-99
0-50
<10
<10
<10
<10

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Milk is sterile at time of secretion from glandular cells (healthy uddder)
Contamination is inevitable (quantity and composition; aseptically: micrococci, streptococci)
Aseptically drawn milk: 100-1000 bacteria/ml
Drawn under clean conditions: 1000-10000 bacteria/ml
Following milking, rate of growth: number&type of bacteria and temperature
Drawn clean (1000-10000 bacteria/ml): doubles in 24-48 hours and reaches next decimal in 72-96 hours at 4 °C . At 10 °C storage, it reaches
1 decimal in 24 hours and 2-3 decimals in 48 hours.
Psychrotropic microorgansisms (e.g.
Pseudomonas fragi ) are present in fresh milk (sources: unsterilized utensils, milking machines, water supply, dust.
Off-flavours: fruity, bitter, sour, oxydised.

Total count 30 °C/ml
Somatic cell/ml
Antibiotic residues
Raw cow milk
≤100 000
≤ 400 00
≤ MRL
Other species’ raw milk
≤ 1 500 000
≤ 500 000
≤ MRL

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Milk drawn from healthy mammary gland contains
3-400000 cells/cm 3
Mastitis is caused by mechanical, chemical or bacterial influences
Cells in milk


From mammary gland: epithelial cells,
From blood: granulocytes, lymphocytes, mononuclear cells (macrophages, giant cells)
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Cell content changes: systemic disease, mechanical influences including (machine) milking, physiological conditions, feeding, housing, stress
Somatic cell count in healthy udder is 30% and it may be increased up to 95% in mastitis

Healthy milk Subclinical mastitis
Clinical mastitis
Cell number 2 x 10 4 -10 5 /ml >5 x 10 5 /ml >10 6
Neutrophyl gr.
≤22%
Lymphocyte ≤ 8 %
>22 %
≥8 %
70-98 %
16% (>40 %)

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Somatic cell ↑
Plasma proteins ↑
 Bovine serum-albumin (BSA) alphaantitrypsine
Ion concentration
 Na, Cl ↑( together with the electrical conductivity ↑)
Intracellular enzymes
 N acetyl-glucose-aminidase (NaGase)
Epithelial cell secretion
 Lactose, fat, casein, ↓

Parameter
Somatic cell
Neutrophyl gr.
NaGase
Catalase
Lysosyme
Lactoferrin
Lactose
αcasein
α -lactalbumin
Bovine-serum-albumin
Na
Cl
Normal value
2-10 x 104/ml
12-22
0,03
0,08
1
0,1-0,2
4,7
13,3
1-1,2
0,1-0,2
24,9
23-29
100
0,9
0,5
0,5
2-10
2
1,2-2
Change (xN)
>10
4-8
>2
>20
>100

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Indirect test
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Mastitest
Whiteside-test
Quantitative method

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SOURCE OF INFECTION
From animal to animal
From enviroment to the udder
MAJOR MICROBES CAUSING MASTITIS
Streptococcus agalactiae, dysgalactiae, uberis, pyogenes animalis, faecium, faecalis, pyogenes humanus
Staphylococcus aureus
Escherichia coli
Klebsiella pneumoniae
Pseudomonas aeruginosa
Algae, fungi

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From the infected udder
During milking, teat cup, rubber,
Cow, calf
Staphylococus aureus, streptococcus agalactiae, Corynebacerium bovis,
Mycoplasma bovis and other Mycoplasma spp., Streptococcus dysgalactiae

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Skin of the animal, teat cup, rubber,
End of milking
(Hand of the workers)
Alveolar epithel cells destroyed
Subclinical (common), clinical form
Watery, flakes,

Staphylococcus aureus
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The incidence of staphylococcal mastitis is increasing (as incidence of streptococcal mastitis decreasing). About 1-1.5 million staphylococci per gram of food must be present for producing sufficient amount of enterotoxin required to induce symptoms in man.
Below 10 °C, no growth and no toxin production take place.
The toxin is heat-stable.
Symptomless humans carry the causative in the nose, and skin but the udder and skin of dairy animal is also infected
(human origin). Milkworkers with cuts, boils and other lesions on hand should not be allowed to handle milk or milk products.
The main-line of protection, however, is to prevent the growth of staphylococci by cooling below 8 ° C as soon as possible.

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Typically from animal to animal
Milking!
No serious clinical symptoms
R
Rarely

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Listeria monocytogenes was isolated from milk and one of the vehicles of the infection (to humans) is considered to be milk.
The organism is able to grow in milk at ambient temperatures.
The control of milk-borne infection with Listeria depends on adequate heat-treatment: 72 °C for 15 sec is sufficient.
Many cases of human listeriosis occurred in the last years following the consumption of different types of soft cheeses which are made from raw milk.
Sheep!

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Streptococcus uberis and other fecal streptococci
Intestine
Lactoperoxidase

 E. coli and Klebsiella

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Endotoxin, mastitis
Acute, peracute alveolar mastitis
Milk amount ↓
Watery, yellow-withish flakes

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Algae
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Prototheca zopfii
Chronic or subclinical mastitis
Fungi

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Due to widespread use of antibiotics in mastitis may lead to increase in incidence of mycotic mastitis. No direct evidence for milk-borne infection to man.
Nocardia asteroides and braziliensis, Candida tropicalis, albicans, krusei were isolated from mastitic udder and from milk. They may survive usual pasteurization processes