THERMODURIC ORGANISMS IN MILK. PART V. A SIMPLIFIED TESTING TECHNIQUE

SUMMARY: Thermoduric colony counts at 30° of laboratory pasteurized milk determined by the roll tube or agar strip methods were lower than those obtained by the standard Petri plate method. The differences in colony count were not of such magnitude, however, as to be likely to result in many errors in grading if a thermoduric bacterial content of greater than 10⁴/ml is accepted as an index of unsatisfactory cleansing of dairy equipment.
The three methods examined were simpler and more economical than the Petri plate technique, but the agar strip method, as described, using the standard loop, was the simplest and gave a sufficiently reliable estimate of the thermoduric colony count for advisory purposes.