MICROBIOLOGICAL AND CHEMICAL STUDIES ON FERMENTED MILK (ZABADY) PRODUCED BY SMALL ARTISANS IN ASSIUT CITY
Abstract: The evaluation of quality and keeping quality of zabady
produced at Assiut city by small artisans was the aim of the
research.
Zabady samples were collected from six small dairies in Assiut
city and stored at 5±2?C in their containers representing the first
group of samples.
As soon as samples of the first group arrived to the laboratory,
one cup from each sample was used as a starter for manufacturing
experimental zabady (the second group of samples) in
reconstituted skim milk (NIDO, 11%W/V) in distilled water.
All samples were analysed daily for: total bacterial count, count
of lactic acid bacteria, coliform and yeast & mold. As well, all
samples were chemically examined for: pH, acidity, total solids, fat,
total nitrogen, total protein and soluble nitrogen content. Regarding
samples of the group I the surface layer of one cup was
asceptically removed, then the surface portion and the bottom
portion were microbiologically analysed separately. On the other
hand samples of the group II were analysed as one portion.
The obtained results showed that at the beginning of
incubation period their was minor difference between the 2
portions of the group I and group II of samples concerning the
total bacterial count. However at the end of the incubation period
some times the surface layer contained higher bacterial counts as
compared with the bottom layer or with group II samples.
On the other hand, the total lactic acid bacteria (L.A.B) counts
showed that the difference between different samples was not
great.
Regarding yeast and mould, the minimum count reached in
group I after 5 days and group II after 7 days and the maximum
count reached in group I after 5 days.
Only 2 samples both from the I and II group were positive for
coliforms overall the storage period.
Concerning chemical determinations, the pH of all samples of
the group I were lower compared to samples of the group II, on
the other hand the acidity was higher.
MICROBIOLOGICAL AND CHEMICAL STUDIES ON FERMENTED MILK
(ZABADY) PRODUCED BY SMALL ARTISANS IN ASSIUT CITY
238
Only one sample from group I contained highest T.S. when
compared to all other samples, in the mean time, all samples of
group II always contained higher T.S.
Concerning fat content, there were great differences, between
fresh samples of group I with minimum value of 2.5% and a
maximum value of 4.7%. Also, percentage of total protein showed
the same trend with a minimum value of 2.676% and 3.662% as a
maximum.
The obtained results showed great differences concerning the
S.N content between samples of group I either at the beginning
and at the end of storage period.
The organoleptic properties examination indicated that their
was big difference between the different samples of the first group,
which may be due to the difference in the raw milk used by each
dairies, on the other side approximately their was no big difference
between the samples of the second group, as no big difference
between the raw material used for manufacturing , also the
samples of the second group always had higher score in
comparison with the samples of the first group, normally this can
be explained by the quality of the raw material used and the
manufacturing process.
Publication year 2012
Organization Name
Author(s) from ARC
External authors (outside ARC)
    منال محمد خضر معهد بحوث تكنولوجيا الأغذية – أسيوط
    نور الهدى محمود حنفي قسم الألبا – كلية الز ا رعة – جامعة أسيوط
    على إسماعيل حسن قسم الألبا – كلية الز ا رعة – جامعة أسيوط
Publication Type Master Thesis
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