الفهرس 
Materials and methodsOnly 14 pages are availabe for public view
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Abstract
Twenty five random samples each of raw milk, cream, ice cream
and kareish cheese were collected from different localities for
enumeration, isolation and identification of psychrotrophic bacteria. The
counts was determined according to the technique recommended by
APHA (1992) using standard plate count agar and incubated at T’C/l 0
days, as well as using modified rapid method (32°C/2 days).
The mean values of psychrotrophic bacterial counts using standard
method were 1.9x 107
, 3.lx108 ,3.3xI06 and 2.6x107 Iml of raw milk
samples, cream samples, ice cream samples and Kareish cheese samples
respectively. While their counts by modified rapid method were 2.3x 107
,2.5x108, 2.8x106 and 1.7x108 /rnl respectively.
These high counts indicate the inadequate hygienic measures
adopted in production and storge and will result in their deterioration and
unacceptability.
Out of 169 isolated psychrotrophes (T’C/l 0 days) from raw milk.
38(22.5%) were Pseudomonas spp.; 23 (13.6%) were Aeromonas spp.; 15
(8.9%) were Staphylococcus spp.; 14 (8.3%) were Bacillus spp., 15
(8.9%) were Micro coccus spp., 17 (10.1%) were Enterobacteriaceae, 10
(5.9%) were Chromobacterium spp., 13(7.7%) were Acinetobacter spp.,
12(7.1%) were Flavobacterium spp., 10(5.9%) were Streptococcus spp.
and 2 (1.1%) were. Alcaligens spp., while out of 180 isolates at 32°C/2
days were, 60 (33.3%) were Pseudomonas spp., 19(10.6%) were.
Aeromonas spp., 17 (9.5%) were Staphylococcus spp., 16 (8.9%) were
Bacillus spp., 14 (7.8%) were Micrococcus spp., 8 (4.4%) were
Enterobacteriaceae, 9 (5%) were Chromobacterium spp., 17(9.4%) were
Acinetobacter spp., 9 (5%) were Flavobacterium spp., 7 (3.9%) were
Streptococcus spp and 4 (2.2%) were Alcaligenes spp. Differentiation of 182 isolates from cream at 7°C/l 0 days revealed
that, 27 (14.8%) were Pseudomonas spp., 18 (9.9%) were Aeromonas
spp., 15 (8.2%) were Alcaligenes spp., 20 (11%) were Acinetobacter spp.,
16 (8.8%) were Chromobacterium spp., 11(6.1%) were Flavobacterium
spp., 28 (15.4%) were Enterobacteriaceae, 22 (12.1 %) were Bacillus spp.,
15 (8.2%) were Micrococcus spp. and 10 (5.5%) were Staphylococcus
spp. while at 32°C/2 days, out of 198 isolates were 38 (19.2%) were
Pseudomoras spp., 25 (12.6%) were Aeromonas spp., 20 (10.1 %) were
Alcaligenes spp., 25 (12.6%) were Acinetobacter spp., 11 (5.6%) were
Chromobacterium spp., 14 (7.1%) were Flavobacterium spp., 32 (16.1%)
were Enterobacteriaceae, 18 (9.1%) were Bacillus spp., 10 (5.1%) were
Micrococcus spp. and 5 (2.5%) were Staphylococcus spp.
Differentiation of 73 isolates from ice cream samples at 7°C/l 0
days revealed that, 15 (20.6%) were Pseudomonas spp., 10 (13.7%) were
Alcaligenes spp., 7 (9.6%) were Acinetobacter spp., 4 (5.4%) were
Flavobacterium spp., 15 (20.6%) were Enterobacteriaceae, 15 ( 20.9%)
were Staphylococcus spp., 5 (6.8%) were Aeromonas spp. and 2 (2.7%)
were Bacillus spp. while out of 76 isolates at 32°C/2 days, were 10
(13.2%) were Pseudomonas spp., II (14.5%) were Alcaligenes, spp., 9
(11.8%) were Acinetobacter spp., 2 (2.6%) were Flavobacterium spp., 16
(21.1%) were Enterobacteriaceae, 14 (18.4%) were Staphylococcus spp.,
5 ( 6.6%) were Micrococcus spp., 4 (5.2%) were Aeromonas spp., and 5
(6.6%) were Bacillus spp.
Differentiation of 150 isolates from kareish cheese samples, at
7°C/l 0 days, revealed that, 23 (15.3%) were Pseudomonas spp., 18 (12%)
were Alcaligenes spp., spp., 8 (5.3%) were Acinetobacter spp., 6 (4%)
were Flavobacterium, spp., 15 (10.7%) were Staplylococcus spp., 26
(17.3%) were Enterobacteriaceae, 12 (8%) were Streptococcus spp., 10
(6.7%) were Micrococcus spp., 15 (10%) were Aeromonas spp. and 16 (10.7%) were Bacillus spp. while out of 156 isolates at 32°C/2 days, were
28 (17.9%) were Pseudomonas spp., 14(9%) were Alcaligenes spp., 10
(6.4%) were Acinetobacter spp., 8 (5.1%) were Flavobacterium spp., 19
(12.2%) were Staphylococcus spp., 20 (12.8%) were Enterobacteriaceae,
10 (6.4%) were Streptococcus spp., 9 (5.8%) were Micrococcus spp., 19
(12.2%) were Bacillus spp. and 19 (12.2%) were Aeromonas spp.
Comparing the psychrotrophic types recovered from dairy products
by appplying standard and modified rapid method, it is recommended
according to our results that modified rapid method could be applied for
detection of psychrotrophic species.
The ecnomic and sanitary importance of psychrotrophs isolated
from examined samples are discussed. Moreover, suggestion control
measures to improve the quality of raw milk as well as other dairy
products were discussed.