Bioscience Methods 2017, Vol.8, No.2, 18-30
23
Table 2 pH and microbial counts of freshly produced snack before packaging for storage
Treatments
Parameter
pH (Mean±STD)
Bacteri (cfu/g) ±STD
Fungi (sfu/g) ±STD
Untreated
9.60±0.1
d
9x10
2
±2.65
a
8x10
2
±6.08
a
Ocimum gratissimum
crude extract
10.53±0.12
b
1x10
2
±1.52
b
5x10
2
±2.08
a
Vernonia amygdalina
crude extract
10.13±0.21
c
7x10
2
±5.51
a
6x10
2
±1.52
a
Mixture of
Vernonia amygdalina
plus
Ocimum
gratissimum
crude extract
11.10±0.15
a
1x10
2
±1.15
b
8x10
2
±2.89
a
Note: Means with the same superscript are not significantly different (P > 0.05).
For fungi, mean count for untreated snacks and snacks treated with
Vernonia amygdalina
plus
Ocimum
gratissimum
crude extract were the same (8x10
2
±2.8 sfu/g). Fungi counts were not significantly different between
the samples.
Five bacteria and eight fungi species were isolated and identified as shown in Table 3 and Table 4.
2.2 Keeping quality
Keeping quality of the snacks in three packaging materials varied with treatments. Physical observation at the end
of keeping/ storage time showed little changes in colour and presence of mould growth as shown in Table 5.
Table 3 Morphological, physiological and biochemical characteristics of bacteria isolated from freshly produced snack before
packaging
Biochemical test
Suspected organisms
Bacillus cereus
Bacillus subtilis
Micrococcus halobulus
Micrococcus luteus
Staphylococcus aureus
Gram stain reaction
+
+
+
+
+
Shape
long rod
long rod
spheres in single cells
spheres in single cells
spheres in single cells
Spore
+
+
-
-
-
Catalase test
+
+
+
+
+
Motility
+
+
-
-
-
Indole production
-
-
-
-
-
Nitrate reduction
+
+
-
-
+
Oxidase
-
-
+
+
+
H
2
S production
-
-
-
-
-
Urase
-
-
+
-
+
Coagulase test
-
-
-
-
+
Dnase
-
-
-
-
+
Glucose
+
+
-
+
+
Sucrose
+
+
+
+
+
Fructose
+
+
+
+
+
Lactose
-
-
-
-
+
Manitol
+
+
-
-
-
Pigmentation on Agar white to cream
slimy whitish
unpigmented
yellow
whitish to orange
Note: + = Positive; - = Negative
