Risk Mitigation in Reducing Thermal Processing with Hurdle Technologies: A Challenge Study in the Canning Industry with Clostridium botulinum.
Tony Savard , Julie Barrette, Michele Marcotte, Reza Zareifard, Stefan Grabowski, Jean-Yves Lecompte
Nom de la revue: European Symposium on Food Safety IAFP's European Symposium on Food Safety 15-17 May 2013 in Marseille, France.
Introduction: As an answer to continuous consumer demand for high quality foods, Agriculture Canada is challenging different techniques to provide microbiologically safe foods with minimal thermal processing damages in support to industries. Hurdle concept combining low pH, organic acids and thermal processing is one of those.
Purpose: Application of selected acidifiers was proposed to provide scientific data to food thermal processing authorities (Health Canada, CFIA and PHA) for new process approval. A full experimental program on selected processing parameters (pH, acidifiers, vegetables and temperature) was initially designed to evaluate the thermal resistance (D and z) of Clostridium sporogenes (PA3679) (as a surrogate to C. botulinum) but preliminary results showed a measured thermal resistance much lower than the one reported in literature for this strain. Therefore, a bio-validation objective with Clostridium botulinum was realized.
Methods: Three food matrices of cut green beans have been tested for survival of a cocktail of C. botulinum (62-a, PC0101AJ0 and 13983B): (1) un-acidified pH 5.8, (2) acidified with LA to pH 4.8, and (3) acidified with GDL to pH 4.8. A spoilage and thermoresistant microorganisms, bacillus stearothermophilus has also been tested for the same food matrices. Final validation (can-size scale) with a stock water-immersion pilot scale retort has been achieved.
Results: Main results indicated that a low acidification treatment is efficient to reduce the intensity of the thermal process needed to ensure safety and long term storage of thermally processed food. Predictive models are useful at mild treatment but are not well adapted at temperature higher than 107°C as the results are not following a linear distribution (D-z model).
Significance: D and z-value of C. sporogenes and C. botulinum could have been overestimated since a long time. Those have been used to design models which are supposed to be linears but our results are not supporting this. Multiples barriers technology shows another potential application in the canning industry combining a light acidification with mild thermal processing to increase the quality of processed vegetable