Results

Table 4.1 : Colonial morphologhy of gram-negative rod bacteria.

Bacteria Colonial morphologyForm Elevation Margin Texture

Salmonella sp Filamentous Flat Filamentous DrySerratia marcescens Circular Umbonate Entire MucoidProteus vulgaris Circular Raised Erose SmoothKlebsiella aerogenes Circular Raised Entire Dry

Table 4.2 : Motility test of gram-negative rod bacteria

Bacteria Motile Non-MotileSalmonella sp √Serratia marcescenes √Proteus vulgaris √Klebsiella aerogenes √

Table 4.3 : Biochemistry test of gram negative bacteria

Bateria Urea Broth TSI Litmus milk

SugarSlant Butt Lactose Sucrose Maltose Glucose

Salmonella sp Negative result:Brown colur urea remained unchanged

Redcolour

YellowColour followed by black colour at the centre (H2S gas)

ReductionNot Fermented

Not Fermented

Fermented Fermented

Serratia marcescens

Negative result:Brown colur urea remained unchanged

Yellowcolour

Yellow colour

Reductioncurd

Not Fermented

FermentedWith gas production

Fermented FermentedWith gasproduction

Proteus vulgaris

Positive result: bright pink colour produced

Redcolour

Yellowcolour followed by black colour at the centre (H2Sgas)

Reduction curd with acid production

Not Fermented

Fermented Fermented Fermented with gas

Klebsiella aerogenes

Negative result:Brown colur urea remained unchanged

Red colour

Red colour followed by black colour at the centre (H2Sgas

Signifies reduction with acid and gas

Fermented

Fermented Fermented Fermented

Nasi Basi Positive result: bright pink colour produced

Yellow colour

Yellow colour

Reduction curd

Fermented with gas

FermentedWith gas

FermentedWith gas

Fermented with gas

Table 4.4: Characteristic pf spoiled food

Type food sample Food spoilage critriaodour texture colour

Nasi Basi Pungent Slimy Creamy