Results

Lactobacillus helviticus is rod-shaped, gram positive, non-sporing, catalase negative, facultative anaerobe. It ferments glucose and lactose, but not sucrose or mannitol. It preferentially ferments lactate.   Its optimum temperature for growth is 45°C, although it can grow at temperatures up to 50-52 °C. It does not grow at 15°C.

(From Bergey’s)

 

 

Growth in Enrichment Conditions:

 

Condition

Picture

Expected Result

Actual Result

Growth on TJA

 

Colony morphology

 

 

 

 

Growth at 45ºC

+

 

small(2-5mm), convex, smooth, glistening, opaque without pigment

 

+

+

 

 

 

small, caramel, convex, smooth

 

+

 

 

 

Test

Picture

Expected Result

Actual Result

Gram Stain

 

 

     Endospore

 

 

 

     Shape

  

+

 

 

-

 

 

 

rod

+

 

 

-

 

 

 

rod

Catalase

-

-

-

Sugar Utilization:

 

 

 

     Glucose

 

 

 

 

 

  

+

+

     Lactose

  

+

-/+

     Sucrose

               

-

-

     Mannitol

-

-