SHAPTON MEDIUM

Bacillus stearothermophillus is a thermophile that is widely distributed in soil, hot springs, ocean sediment, and is a cause of spoilage in food products. It is commonly used as a challenge organism for steam sterilization validation studies. Flat sour spoilage occurs chiefly in low acid foods, such as peas, corn and lima beans but can also occur in medium acid foods such as spinach, green beans etc. Shapton and Hindes formulated the medium for the enumeration of spores of Bacillus stearothermophilus, which cause flat sour spoilage in canned foods with pH more than 4.5.
The sample under test is suspended in Ringers salt solution and then added to sterile molten Shapton Medium and is held at 100?C for 20 minutes. Then the temperature is slightly raised to 108.4?C and maintained for 10 minutes after which this is cooled to 50?C and plates are poured. The plates are incubated at 55?C for 48 hours.

for enumeration of Bacillus stearothermophilus spores from canned foods with pH>4.5