Challenge studies with Clostridium botulinum in high moisture bakery products packaged under modified atmospheres

High moisture, low acid crumpets and pizza supported growth of and toxin pr oduction by Clostridium botulinem when initially packaged in high gas barri er bags either in air or under modified atmosphere conditions and stored at ambient temperature. English style crumpets (a(w) 0.990), pizza crust (a(w ) 0.960), and bagels (a(w) 0.944) were inoculated with a mixture of C. botu linem types A and proteolytic B spores (5 x 10(4) spores/g), packaged in ai r, in air with an oxygen absorbent, or in a CO2/N-2 (60:40) gas mixture, st ored at 25 degrees C for 42 days and then monitored for toxin. All crumpets and pizza were toxic at the end of storage, irrespective of initial packag ing atmosphere; however, no toxin was detected in any bagels. At 42 days, a ll bakery products were sensorially unacceptable.