Notes on the technology of milk powder and the faults that may occurs during storage. Besides, the manufacture of instant milk powder and how to modify cow milk to produce humanized milk.

1. Milk powder
April,2020 1Dr.Dina A. B. Awad

2. Dried milk powder
Dried milk
powder
Whole milk
Skimmed milk
Cream
Whey
Butter
Shelf life: 6 months to 2 years
from Types
Whole milk powder
Skimmed milk powder
Butter milk powder
Water%
4%
5%
4%
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April,2020 Dr.Dina A. B. Awad

3. Selection & preparation of milk
clarified , standardized milk at 4ºc
Preheated, homogenized, stabilized ,conc. milk
Spore& thermodurics bacteria
Color& flavour abnormalities
Clafication by centrifugal separator
Milk standardization (fat %)
Casein stabilization
preheating
Drying
Homogenization
Milk powder
Rabid cooling??
Concentration under vacuum below 70º c (1/3 or 1/5)
Whole milk not less than 25%,
skim milk not more than 1.5%
Technological steps of milk powder
(spray or roller method)
Package
3April,2020 Dr.Dina A. B. Awad

4. Spray method
4
Concentration milk is sprayed through nozzle
(under high pressure high temperature or
rotating atomizer) into fine particles to a hot
chamber with hot dry air current(160-250c)
Uniform round regular particles with
diameter ranges from 5-10 micron.
Packed under vacuum in cans ????
April,2020 Dr.Dina A. B. Awad

5. Hot chamber
Packed under vacuum replace air
inside it by inert gas as N2 or CO2
Concentrated milk
Hot air current 160-250º c
Particle size 5-10 micron 5
Spray method
April,2020 Dr.Dina A. B. Awad

6. Concentrated milk will spread
on the drum surface in the
form of Thin film and milk will
dry within 6-30 sec. in the
form of sheets & removed by
special knives . The product is
usually passed through brush
shifter which break the
product into relatively uniform
powder prior to packing.
The powder is packed into
25kg sacks
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Roller method
Concentrated milk
Double Drum
Heated internally at
150 c /12-17 rpm
April,2020 Dr.Dina A. B. Awad

7. The same as in atmospheric roller method but:
1- The temperature used is 55-65ºc
2- The product is of better solubility, higher nutritive value and no change in milk constituents.
Vacuum roller method
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Unfortunately , It loss some
vitamins like B1, B6, B12
and vit.C and loss of some
minerals.
Nutritive value Uses of milk powder
Used like fluid milk in yogurt
manufacture,
ice-cream, infant baby food,
chocolate industry
April,2020 Dr.Dina A. B. Awad

8. Microrganisms may gain access to
powder are ( thermodurics
Micrococci, strept. thermophilus ,
strept faecalis) , (aeropic spore
former like B.subtilis) and coliform.
Microbiology of
spray dried milk
Microbiology of
roller dried powder
The recovery of the dried product from the
roller presents the first post-drying hazard.
Contamination may occurs due to manual
contact with powder during collection by hand
scan by staphylococcus aureus and salmonella.
Raw milk is of great significance …it should be of good hygienic quality and
low count thermodurics and spore former bacteria.
So preheating process is very important to avoid serious contamination.
Packing process should be done under strict hygienic measures.
Microbiology of milk powder
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April,2020 Dr.Dina A. B. Awad

9. Defects of milk powder
Oxidized
flavour
Tallow
flavour
Unsaturated
fatty acids
O2 & Cu
perioxides
Ketons &
aldhydesHigh storage
temp.
9April,2020 Dr.Dina A. B. Awad

10. Defects of milk powder
Fishy
flavour
Stale
flavour
Lecithin
Loss of solubility & stale
flavor& deterioration of
casein (dark color spots )
brown color
Trimethyleamines
High temp.
High moisture
temp.
High moisture
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April,2020 Dr.Dina A. B. Awad

11. Defects of milk powder
Off
flavour
Rancid
flavour
Milk
Hydrolytic flavour
Milk powder
with unpleasant
flavour
Lipase
Microbial or
physiological
source
x
Milk fat
11April,2020 Dr.Dina A. B. Awad

12. Instant milk powder
“Agglomerated milk powder”
Spray dried milk powder has a good solubility , but it
deficient to be wetted, sink or dispersed rabidly ------
moreover when added to water------its proteins tend to
form a sticky substance -------- to form lumps -----so, its
complete reconstitution is very difficult even with agitation
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April,2020 12Dr.Dina A. B. Awad

13. Instant Milk
powder
When
added
to cold
water
Good Wettability &
short wetting time
Good Dispersability
Good Sinkability
Good solubility
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Milk powder
better
reconstitution
properties
Wettability
Dispersability
Sinkability
Than normal milk powder.
April,2020 Dr.Dina A. B. Awad

14. Manufacturing Instant skim milk powder
1- Wetting of the milk powder particles
2- Re-drying by hot air under vacuum to evaporates excess of moisture (as during wetting
moisture Increased to 6-12%).
3- Remove undesirable coarse particles & give homogenous size.
4- Sudden cooling.
5- Packing under vacuum by using inert gas in laminated polyethylene bag ?????
Milk powder 5%
water & low
solubility
Humidifed or
wetting
Alggomerate
Milk powder
Redrying at hot air
250 c 5% water&
90%soluble
April,2020 14Dr.Dina A. B. Awad

15. 15
- Uniform wetting of particles
surface by steam or water
mist or (milk is humidified
water 16-18% ).
- The powder will pick
up water and swell
quickly .
- The globules will adhere
to each other forming
agglomerate.
•Aim: agglomeration of milk particles will give porous aggregates and increase the
interstitial air between particles ----so reconstitutions start when air replaced by the
water --- at this time agglomerates will sink rapidly.
April,2020 Dr.Dina A. B. Awad

16. 16April,2020 Dr.Dina A. B. Awad

17. 17
Manufacturing Instant whole milk powder
1- Wetting of the milk powder particles
2- Re-drying by hot air under vacuum to evaporates excess of moisture (as during wetting
moisture Increased to 6-12%).
3- Remove undesirable coarse particles & give homogenous size.
5- Sudden cooling.
6- Packing------- As instant whole milk powder ---------sensitive to fat oxidation ------so it packed
with inert gas & protected in metal cans
4- lecthinization.
Milk powder 5%
water & low
solubility
Humidifed or
wetting
Alggomerate
Milk powder
Redrying at hot air
250 c 5% water&
90%soluble
April,2020 Dr.Dina A. B. Awad

18. 4* lecithinization.
Fat globule agglomerates
Water less than 45ºc
not reconstitute
In a condition
x
Spraying mixture of lecithin & butter
oil (1:1) at 60ºc
Final lecithin % 0.2-0.3% in
powder
Lecithinization gives more free
Fat surface to obtain higher
degree of dispersion
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Hydrophobic nature
Due to hydrophobic nature of fat agglomerates contain fat will not
Reconstitute well unless water with temp 45ºc so whole milk particles
coated with active or wetting substances a good emulsifier
April,2020 Dr.Dina A. B. Awad

19. Reconstitution
The wetting time of instant skim milk powder ------not more than 15 sec.
Factors affecting solubility of instant skim milk powder
Good
wettability
Ability to
sink
Good
dispensability
Good
solubilityIt depends on particle size
Ideal size 130-135micro.
Soluble in less than 30sec.
Relations??
Large size particle
has more time to
sink
Resemble normal milk
Without lumps, without
sediment, without
floating on the surface
Spray method 99%
Roller method 95%
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April,2020 Dr.Dina A. B. Awad

20. Baby milk powder
Under certain conditions women are unable to feed their babies , so
highly developed powder food are manufacture from cow’s milk.
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If depend on cow’s milkCow’s milk
average/100ml
Human milk
(average/100ml)
Constituent
Higher pt intake3.31.5Total protein
20%60%Whey
80%40%Casein
3.53.3Fat
different4352Unsat.fatty acid
different5748Sat.fatty acids
Less lactose4.77Lactose
higher0.720.21Minerals
66 Kcal72 KcalEnergy
April,2020 Dr.Dina A. B. Awad

21. production of humanized Baby
milk powder from cow’s milk
Correction of protein :Correction of fatty acids :
Correction of minerals:Correction of Lactose :
-Addition of whey pt conc.
- addition of demineralized water
- Mixture of vegetables &
butter oils to increase
unsaturated fatty acids
-Addition of demineralized whey
or mineral mixture as Ca,Mg, Fe,
phosphorus
- avoid adding K,Na,Cl.
-Adding demineralized
whey or lactose
Correction of Vitamins:
-Adding vit.mixture A,D and C
N.B: Baby foods should be contain not more than 50 m.o /gram and free from pathogens
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April,2020 Dr.Dina A. B. Awad

22. Requirement for well balanced Recombined milk
It is liquid milk which resemble fresh milk that result from addition of water to skim
milk powder with addition of AMF to reach the desirable fat content according to the
legal standard in the presence of suitable emulsifier.
Def. Recombined milk
Recombined milk ,Means-----skim milk powder + water + AMF.
water
AMF
Skimmed milk powder
Good quality, free from heavy metals& impurities, not hard water??1-
2-
3-
cream or butter, pure state 99.8% fat, not need refrigerated storage.
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April,2020 Dr.Dina A. B. Awad

23. Thank you for attention
Presented by :
Dr. Dina A. B. Awad
Lecturer of food hygiene department
Faculty of veterinary medicine
Benha university , Egypt
April,2020 23Dr.Dina A. B. Awad