Bioscience Methods 2017, Vol.8, No.2, 18-30
22
A drop of human plasma was added to one of the suspensions and stirred for 5 seconds with the other suspension
as a control. A coagulase positive result was indicated by clumping which did not re-emulsify.
1.8.3 Motility test
Motility media was prepared according to the manufacturer`s (Oxoid
®
) specification by weighing (53 g per Litre:
England), this was used to demonstrate the motility of organism due to flagella. 18-24 hours old organism was
stabbed on the agar and incubated at 37°C for 24-48 hours. Motile bacteria were identified by their movement
through the stabbed agar from top to bottom.
1.8.4 Urease test
A little of the culture of the test bacteria was streaked over the surface of the agar slant of urease test medium with
phenol red as indicator and incubated at 37°C for 7 days. A control of the basal medium containing no added urea
was equally inoculated. A colour change of the medium from yellow to pink or red indicated a positive result and
no colour change indicate a negative result (Fawole and Oso, 2001).
1.8.5 Oxidase test
A piece of filter paper was placed in a sterile Petri dish and 2-3 drops of freshly prepared oxidase reagent was
added. Using a sterile glass rod, a colony of the test bacterium was picked and smeared on the filter paper and
observed for 10 seconds. The presence of blue-purple colour indicates a positive oxidase while absence of
blue-purple colour indicates a negative oxidase test (Fawole and Oso, 1998).
1.8.6 Tests for indole production
A young culture of the test organism was inoculated into 10 mls peptone water in test tubes and incubated at 37°C
for 7 days, Kovac`s reagent (0.5 mls) was added to each test tube and the test tubes were shaken gently and
allowed to stand. A rose-purple colour developed in the presence of indole Famurewa et al. (2009).
1.8.7 Tests for sugar fermentation
A 1.0% NaCl, fermentable sugar and 0.01% phenol red were used to prepare the medium. The medium (5 mls)
was dispensed into test tubes containing inverted Durham`s tubes after which they were sterilized at 115°C for 15
minutes. The test tubes were inoculated with 18-24 hour old culture of the test organisms and incubated at 37°C
for 5 days. The test tubes were observed and the presence of yellow colour instead of red indicates fermentation
Famurewa et al. (2009).
1.8.8 Statistical analysis and data presentation
Data were subjected to one-way analysis of variance (ANOVA) and the means separated using Duncan`s Multiple
Range Test. Statistical Analysis System
(SAS
®
), version 9.1 package was employed for statistical analysis at 5%
confidence level. Data were presented in mean±, percentile, as well as frequency, pie and bar chats as appropriate.
2 Results
2.1 Microbial qualities
The result for pH and microbial analysis of freshly produced snack is presented in Table 2. It showed that the
mean pH value ranged from 9.60 ±0.1 – 11.10 ±0.15; mean bacteria count ranged from 1x10
2
±1.15 – 9x10
2
±
2.65 cfu/g and fungi mean count ranged from 5x10
2
±2.08 – 8x10
2
±2.89 sfu/g.
The untreated snacks had the least mean pH value (9.60 ±0.1) and the highest mean bacteria count 9x10
2
±2.65
cfu/g which were significantly different.
Snacks treated with Mixture of
Vernonia amygdalina
plus
Ocimum gratissimum
crude extract had significantly
highest pH value 11.10 ±0.15 its bacterial count was the same with snacks treated with
Ocimum gratissimum
crude extract 1x10
2
±1.15 cfu/g as the least.
