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21 Φεβ 2013 (πριν από 4 χρόνια και 1 μήνα)

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Warsaw Agricultural University


Faculty of Food Technology

1

Address: ul. Nowoursynowska 159c, 02
-
787 Warsaw, Poland


phone: +48 22 8478699,

fax: +48 22 8478699,

tzy_dziekan@alpha.sggw.waw.pl


Dean:


Prof. dr hab. Andrzej Lenart


Vice Deans:

Prof. dr hab. Wanda Duszkiewicz
-
Reinhard (Science)

Dr Zbigniew Pałacha (Didactic)

Prof. dr hab. Jan Mroczek (Didactic)

Faculty of Food Technology

2

Faculty of Food Technology

Department of Chemistry

Department of Food Technology

Department of Food Engineering

and Process Management

Department of Biotechnology,

Microbiology and Food Evaluation

3


Division of Food Biotechnology and Microbiology



Division of Milk Biotechnology



Division of Food Quality Evaluation

Department of Biotechnology,

Microbiology and Food Evaluation

4

Division of Milk Biotechnology

Academic staff:

Prof. dr hab. Stanisław Zmarlicki

Dr Anna Berthold

Dr Antoni Pluta

Dr Małgorzata Ziarno

Mgr Katarzyna Kycia

Prof. dr hab. Irena Molska (retired)


Tech. & admin. staff:

Mgr Jadwiga Grymanowska

Zofia Musińska

5

„ Milk and dairy products quality
improvement



investigations carried out

at the Division of Milk Biotechnology

of Warsaw Agricultural University ”

Dr Antoni Pluta

Head of the Division of Milk Biotechnology



tel./fax. +48 22 853 09 12

tzy_ztmm@alpha.sggw.waw.pl

6

Preparations for the EU accession
enforces many changes in polish dairy
industry

improvement of dairy product quality

modernisation

of farms

modernisation

of dairy plants

improvement

of raw milk quality

improvement

of production hygiene

7

cooling chain

„ Microbiological and physicochemical
quality of the raw milk ”

Coordinators
:

all team

8

0

10

20

30

40

50

60

70

80

90

100

1997

1998

1999

2000

2001

2002

Quality of raw milk delivered to 3
dairies in the North
-
West region

of Poland

years

% of raw milk

> 10
6

CFU/ml

out of class



㄰1
6

CFU/ml

II class



㐠4‱
5

CFU/ml

I class



㄰1
5

CFU/ml

Extra grade

„ Microbiological and physicochemical
quality of market dairy products:
pasteurized milks, fermented milks,
cheeses, milk powders, ice creams ”

Coordinators
:

all team

10

Years 1995
-

1997 Years 1998
-

2002

The microbiological quality

of market yoghurts

5%

10%

85%

100%

> 10
2

CFU/g

< 10
1

CFU/g

10
1



10
2

CFU/g

11

% of samples with coliform bacteria

The number of
S. thermophilus


and
L. bulgaricus

in market yoghurts

11

3%

3%

15%

79%

16%

4%

28%

52%

>10
8

CFU/g

10
7

-

10
8

CFU/g

<10
6

CFU/g

10
6

-

10
7

CFU/g

>10
7

CFU/g

10
6

-

10
7

CFU/g

<10
5

CFU/g

10
5

-

10
6

CFU/g

S. thermophilus

L. bulgaricus

„ Methods for testing milk

and milk products


Coordinator
:

Prof. dr hab. Stanisław Zmarlicki

12

-

very small numbers of coliforms and Gram
-
negative bacteria in pasteurized milk,

-

psychrotrophic bacteria spores in pasteurized
milk,

-

antibacterial residues in milk.

Simple and fast methods were developed

for detection:

Method to ensure oxygen free atmosphere for
incubation of anaerobic bacteria cultures.

13

„ Occurence and characteristic

of Bacillus cereus

in raw milk and environment ”

Coordinator
:

Dr Anna Berthold

14


thermoduric,


associated with milk defects (off
-
flavours,


sweet curdling, „bitty cream”),


some strains are able to grow at 6
0
C,


associated with outbreaks of food


poisoning.

predominant organism that determines

the quality of pasteurized milk


Bacillus cereus

15

Researches included:


indication of occurence of
B.cereus

in raw
milk and farm environment,


investigation of isolated
B.cereus

strains


some biochemical features (API 50CHB),


growth characteristics in milk stored in 4


8
0
C/14 days,


production of diarrheal enterotoxin in milk.

16

B.cereus

were isolated from some raw
milk samples and all environmental
sources on farms (soil, grass,
bedding, feed, air, faeces, udder).

B.cereus

strains capable to producing the
diarrheal enterotoxin were detected in raw milk
and farm environments.


8% of the
B.cereus

strains were psychrotrophic.

17

„ Development of a simple method for
production of yoghurt cheese
characterized by high calcium content ”

Coordinator
:

Prof. dr hab. Stanisław Zmarlicki

18

Quarks contain low calcium because about
80% of calcium present in milk is lost with the
whey.


One of the methods to overcome this
problem is applying ultrafiltration (UF) of milk
before its acidification.

19

Using proper level of UF concentration of milk
and its acidification to pH 5,2 with yoghurt
culture, it is possible to obtain good quality
acid curd cheese, containing twice as much
calcium as its counterpart produced by
traditional method.

20

Coordinator
:

Dr Antoni Pluta

„ The influence of the technological
parameters and the type of dairy culture
starter on proteins, lipids and sensoric
changes of low fat Dutch type cheese ”

21

The lowering of fat content by 50% in Dutch
type cheese results in worsening of its sensoric
value.


The aim of the study was the optimization of the
low fat (15
-
16%) Dutch type cheese production.
The research was carried out in the industry
scale.


The cheeses were characterized in respect

of the physicochemical, microbiological

and sensoric properties.

The demand for low fat products
especially cheeses still increase.

22

The addition of skim milk powder, lecithin

and the thermised dairy starter cultures to
cheese milk, lowering of scalding temperature,
increasing the amount of rinsing water allow

to obtain low fat Dutch type cheese with a 50%
fat content reduction without any decrease

in quality and yield.


The number and type of microflora were not
related to the deterioration of the sensoric
properties of low fat cheese.

23


The impact of modified atmosphere
packing on the quality of cheese
s ”

Coordinator
:

Dr Antoni Pluta

24

The most popular method of cheeses packaging
is the vacuum packaging.


Packaging in modified atmosphere could extend
shelf life of cheeses.


The study involved microbiological and
physicochemical determinations as well as
organoleptic evaluation of grated Mozzarella
cheese and tvorog.

25

All modified vacuum atmosphere
packaging
systems
(100% CO
2
, 100% N
2
,

vacuum
)
prevented fungal growth
on
tvorog
as compared
to ordinary
packag
ing in air
. The only observed
disadvantage of packing in atmosphere 100%
CO
2

was strong syneresis of whey during
storage.

A significant effect was observed

of pack
ag
ing
of grated Mozzarella
in the
atmosphere of
CO
2

on the inhibition

of the development of microflora
compared to pack
ag
ing in the
atmosphere of
N
2

and mixture

of
CO
2

and
N
2
.

26


Application of ultrafiltration in the
production of cheese base suitable

for processed cheese manufacture



Coordinator
:

Mgr Katarzyna Kycia

27

Inclusion of whey proteins in cheese, thereby
increasing cheese yield,

Minimizing the cost connected with milling
cheeses before melting (cheese base have
smooth, creamy texture),

Reducing cost of storage young and
ripened
cheeses.

R
easons for undertaking this study:

28

This study has demonstrated the
possibility
of producing processed cheese with cheese
base obtained from UF milk.


In further studies some ripening agents will
be added to the UF retentat
e

and
higher
substitution of cheeses will be considered.

29

Coordinator
:

Dr Małgorzata Ziarno

„ Fortification of dairy products with
calcium: drinking
milk, fermented milk,
cottage cheese, quark ”

30


The consumption of quark, cottage cheese
and buttermilk is relatively high in Poland.

They are not as good source of calcium as
rennet cheese and yoghurt per serving.

R
easons for this study:


Calcium fortification of these dairy
products can improve their nutritional value.

31

Soluble form of calcium appeared to be
preferable for calcium supplementation of
processing milk for quark.


Application of insoluble form of calcium made
possible fortification of fermented milks or
processing milk for cottage cheese.

32