Comparison of electrolized water and multiple chemical sanitizer action against heat-resistant molds (HRM)

Abstract

This study aimed to evaluate the sensitivity of heat-resistant molds isolated from spoiled thermally processed foods to antimicrobial compounds used for food industry sanitation. An ortho-phenylphenol-based smoke generator sanitizer, liquid chemical sanitizers (benzalkonium chloride, biguanide, iodine, peracetic acid, and sodium hypochlorite), and acidic and alkaline electrolyzed water were used against Aspergillus australensis (MB 2579; NFF 02), Aspergillus aureoluteus (NFC1), Paecilomyces fulvus (PFF 01), Paecilomyces niveus (PNT 01; PNDC 01; PNB1 01), and Paecilomyces variotii (PV 01; PV 01; PVCH 03). The fungal strains were exposed separately to liquid sanitizers and electrolyzed water in stainless steel discs for 15 min following the European Committee for Standardization (CEN) recommendations. Moreover, the fungal strains were exposed to the smoke generator sanitizer for 7 h following French protocol NF-T-72281. The best results of fungal inactivation were achieved when the highest concentration specified in the label of these sanitizers was tested. On the opposite, the lowest concentration specified in the label should be avoided since it was ineffective in most cases (94%). The ortho-phenyphenol-based smoke generator sanitizer and peracetic acid (1%) showed the best results of spore inactivation, while iodine and benzalkonium chloride achieved satisfactory results against the strains evaluated. Sodium hypochlorite and biguanide were ineffective against most of the fungi studied at all concentrations tested. Acidic and basic electrolyzed water was also ineffective to achieve the 3-log CFU reduction required in the concentrations tested. In general, Paecilomyces spp. was more sensitive than Aspergillus spp. against all sanitizers evaluated, whereas A. aureoluteus NFC1 was resistant to all agents and concentrations tested. The heat-resistant fungal strains showed varied sensitivity against the different agents. Notably, the two most effective commercial sanitizers against the heat-resistant strains were ineffective against the filamentous fungi recommended for sanitizer testing (A. brasiliensis ATCC 16404), which demonstrates the relevance of testing fungal isolates that cause spoilage to choose the most effective compound and obtain the best results of fungal control.

Keywords: Benzalkonium chloride; Food industry; Fungi; Peracetic acid; Sanitization; Smoke Tech.