Study of the impacts of electro-activated solutions of calcium lactate, calcium ascorbate and their equimolar mixture combined with moderate heat treatments on the spores of Bacillus cereus ATCC 14579 under model conditions and in fresh salmon

Bacillus cereus as an Underestimated Foodborne Pathogen and New Perspectives on its Prevalence and Methods of Control: Critical and Practical Review

“…Meanwhile, the high reactivity exhibited by these solutions due to their metastable state makes them suitable for use as antimicrobial agents in many fields such as food industry, medical facilities, etc. , Along the same lines, Cayemitte et al (2021) used a reactor modulated with ion exchange membranes to produce very acidic electroactivated solutions (pH 1.94–2.16, p K a 2.90–3.14 and titratable acidity 0.102–0.109 mol/L) from calcium ascorbate and calcium lactate organic salts submitted to an external current electric intensity of 750 mA for a maximum of 30 min. They observed that these EAS were highly sporicidal, achieving a reduction in B. cereus ATCC 14579 endospores of 8.53 log CFU/mL and 9 log CFU/mL (initial count of 10 9 CFU/mL) after 5 min of direct contact with the EAS-calcium lactate and the EAS-calcium ascorbate, respectively . In another article (in press) covering the application of such EAS (calcium ascorbate and calcium lactate) on vegetative cells of B. cereus ATCC 14579, the authors obtained 7 log reduction of the cells (initial count of 10 7 CFU/mL) after only 5 s exposure time to the EAS.…”

“…The endospores of B. cereus can be identified in particular by their shiny and regular appearance when they are observed under a phase contrast microscope or following their staining with malachite green . In general, for confirmation of endospores in a medium, one of the procedures is to heat a homogenized inoculated solution (e.g., 75 °C/15 min or 80 °C/10 min) to destroy the vegetative cells and then incubate 1 mL of the solution on MYP medium, and if colonies are detected, a hemolysis test can be used for confirmation. , In 2020, Vidic et al reported a new approach using aptamer-based biosensors as reliable techniques implemented for the detection of B. cereus endospores in dairy products . Additionally, the authors mentioned that dipicolinic acid can also be used as a good biomarker for the detection and estimation of endospores of B. cereus in media, including other aerobic endospore-forming bacteria as well as anaerobic Clostridium in food products (e.g., milk and dairy products).…”

“…They observed that these EAS were highly sporicidal, achieving a reduction in B. cereus ATCC 14579 endospores of 8.53 log CFU/mL and 9 log CFU/mL (initial count of 10 9 CFU/mL) after 5 min of direct contact with the EAS-calcium lactate and the EAScalcium ascorbate, respectively. 108 In another article (in press) covering the application of such EAS (calcium ascorbate and calcium lactate) on vegetative cells of B. cereus ATCC 14579, the authors obtained 7 log reduction of the cells (initial count of 10 7 CFU/mL) after only 5 s exposure time to the EAS. Moreover, scanning electron microscopy (Figure 6) revealed severe damage to the cell membranes (e.g., pores, ruptures) reflecting the effectiveness of EAS and their potential to be used as antibacterial agents in food processing.…”