Moorella thermoacetica, a thermophilic anaerobic bacterium, is found in 36% of 55°C non-stable spoiled LACF analyzed between 2001 and 2010 by CTCPA. This species can form spores able to survive sterilization process and germinate, leading to food alteration. A better understanding of the growth and sporulation abilities of this bacterium according to conditions encountered during canning process would provide clues to limit non-stability occurrence without increasing sterilization temperatures. Thus, growth and sporulation were studied for M. thermoacetica ATCC 39073 at optimal temperature with or without pH regulation. Heat-resistance was also determined for spores produced on rich solid medium. Non-regulated cultures were performed in AMSCO flasks at 55°C in DTBmod medium under CO2 atmosphere. Regulated growth was conducted in pH-controlled batch fermentor at 55°C in DTBmod continuously sparged with CO2, inoculated either with a late-exponential-phase pre-culture or a heat-activated spore suspension. Growth was followed by optical density (OD) measurements, total bacterial and spores counts. Growth parameters (maximum growth rate, μmax and lag phase) were determined using modified Gompertz model applied to OD measurements. Three batches of spores of the reference strain were produced on MLA plates at 55°C and heat resistance was determined in phosphate buffer at pH 7.0. During growth of M. thermoacetica in regulated conditions, a strong decrease of pH from 7 to 4,5–5 was noticed. Surprisingly, the initiation of sporulation was triggered during early exponential growth which could result from the pH decrease of the medium, as observed for solventogenic Clostridium organisms. However, M. thermoacetica also sporulated under regulated optimal conditions, showing that the decrease of pH was not directly responsible for the initiation of sporulation. Moreover, a strong decrease of redox potential from about −300 mV to −500 mV was noticed during regulated growth. In regulated and non-regulated conditions, the μmax was similar. The lag time was estimated at 8.3 h and 17 h for regulated cultures inoculated with cells and spores respectively. Spores produced at 55°C exhibited a mean D130°C of 5.7 min. Our results showed that M. thermoacetica ATCC 39073 was able to trigger sporulation during early exponential growth phase at optimal temperature whether pH was regulated or not. Spores of M. thermoacetica were shown to be highly heat-resistant. This also highlights the potential of Moorella to form highly resistant spores in canned food industry. Further work is running to understand high heat resistance of M. thermoacetica.