T9-01 Spores under High-pressure High-temperature Processing Conditions

Wednesday, July 12, 2017: 8:30 AM
Room 15 (Tampa Convention Center)
Brigitte Cadieux , McGill University , Ste-Anne-de-Bellevue , Canada
Hamed Vatankhah , McGill University , Ste-Anne-de-Bellevue , Canada
Lawrence Goodridge , McGill University , Ste-Anne-de-Bellevue , Canada
John W. Austin , Health Canada , Ottawa , Canada
Hosahalli S. Ramaswamy , McGill University , Ste-Anne-de-Bellevue , Canada
Introduction: Spores produced by Clostridium botulinum are highly resistant to heat and require long processing times to become inactivated. This can lead to the deterioration of food quality. High Pressure High Temperature (HPHT) processing is an alternative technology that can produce safe foods while maintaining the highest quality of the product.

Purpose: The goal of this study was to evaluate the destruction kinetics of group II (nonproteolytic) C. botulinum spores under various HPHT processing conditions.

Methods: Group II C. botulinum spores produced by eight strains from different serotypes (B, E, F) were suspended in ACES buffer (106 spores/ml) and individually processed at 600 MPa, 80°C. To determine the D-value, spore survival was enumerated by plate count on McClung Toabe agar with egg yolk and the plates were incubated anaerobically for seven days at 25°C. Spores exhibiting the highest resistance were further processed at 550 and 650 MPa at 80°C. The z-value as a function of pressure was, later, calculated. Each treatment was repeated in triplicates.

Results: Spores from C. botulinum type F strains exhibited the highest D-values (3.2 to 7.3 minutes) upon processing at 600 MPa at 80°C, followed by type B strains (2.4 to 5.8 minutes) and type E strains (2.6 to 2.7 minutes). Strains 610F, KAP-B-8 and E Russ showed the highest resistance within their respective type and were selected for subsequent experiments. The D-values of these three strains increased at 550 MPa (7.4 to 36.2 minutes) and decreased at 650 MPa (2.0 to 6.0 minutes). Based on the z-value, strains KAP-B-8 and 610F produced spores which were the most resistant to HPHT (128.2°C and 153.8°C, respectively), while spores from E Russ were the least resistant (200.0°C).

Significance: HPHT is an effective method for destroying C. botulinum spores and could potentially be used as a processing method to achieve commercial sterility while maintaining the quality of food products.