Description

Use and description:

It is used for the cultivation of aciduric microorganisms associated with spoilage of products. The low pH of fruit juices makes citrus fruit products susceptible to spoilage by yeasts, molds and the bacteria Lactobacillus and Leuconostoc. According to Hays investigation in the 1950s about spoilage in frozen concentrated orange juice, he found that an agar medium containing orange serum juice was superior to Lindegren Agar in isolating the microorganisms responsible for spoilage causing a buttermilk off-odor. Orange Serum Agar is recommended for examining fruit beverages.

 

Composition per litre:

Orange Extract ……………….…..4.0 g

Peptones……………………………13.0 g

Potassium Phosphate ………….3.0 g

D-Glucose anhydrous…………..4.0 g

Agar ………………………………….16.0 g

 

Final pH of the ready to use medium:   5.5±0.2 at 25.0 °C

 

Medium preparation:

Add 40.0 grams of dehydrated culture medium to 1 litre of distilled water.

Autoclave for 15 minutes at 121oC.

 

Quality specifications:

  1. The powder is homogeneous, free flowing and light beige.
  2. Ready to use medium:  trace to slightly hazy and light to medium yellow-beige

 

Microbiological response after 18-24 hours at 48 °C:

OrganismGrowthInnoculum 
Aspergillus niger ATCC 16404good growthpoint innoc.
Lactobacillus casei ATCC 393good growth10-300
Lactobacillus fermentum ATCC 9338good growth10-300
Lactobacillus plantarium ATCC 8014good growth10-300
Saccharomyces cerevisiae ATCC 9763good growth10-300

 

Storage:

Store the sealed bottle containing the dehydrated medium at 2 to 30°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the colour has changed from the original light beige colour.

500g wrapped pots