EVALUATION OF 4 PEA (PISUM-SATIVUM) CULTIVARS IN PE-2 MEDIUM FOR THE MPN ENUMERATION OF ANAEROBIC SPORE-FORMING ORGANISMS

Untreated 'Alaska' seed peas have traditionally been used to prepare P E-2 medium, a medium used to recover anaerobic bacteria. Three cultiva rs of seed peas, 'Columbian', 'Yellow', and 'Scotch' were compared to the cultivar 'Alaska' peas in PE-2 for recovery of Clostridium butyric um ATCC 860, Clostridium sporogenes ATCC 7955/NCA 3679, and Thermoaner obacterium thermosaccharolyticum ATCC 25773 determined by using the mo st probable number (MPN) technique. Organisms were grown in cooked mea t medium (CMM) and enumerated by the three-tube MPN method in PE-2 med ia incubated at 37 degrees C for 48 h. Recovery of C. butyricum and T. thermosaccharolyticum grown in homogenates of commercial cream-style corn and vegetable beef soup were also evaluated. Similar recovery of organisms from stock cultures or from foodstuffs were observed in PE-2 prepared with three of the pea cultivars ('Alaska', 'Columbian', and 'Yellow'). While the 'Scotch' cultivar PE-2 medium yielded recoveries comparable to PE-2 prepared with the other pea cultivars, turbid tubes were occasionally observed from which viable microorganisms could not be recovered. This cultivar is therefore not recommended due to the p robability of yielding false positives in the MPN technique.