Sea salts as a potential source of food spoilage fungi

Abstract

Production of sea salt begins with evaporation of sea water in shallow pools called salterns, and ends with the harvest and packing of salts. This process provides many opportunities for fungal contamination. This study aimed to determine whether finished salts contain viable fungi that have the potential to cause spoilage when sea salt is used as a food ingredient by isolating fungi on a medium that simulated salted food with a lowered water activity (0.95 a). The viable filamentous fungi from seven commercial salts were quantified and identified by DNA sequencing, and the fungal communities in different salts were compared. Every sea salt tested contained viable fungi, in concentrations ranging from 0.07 to 1.71 colony-forming units per gram of salt. In total, 85 fungi were isolated representing seven genera. One or more species of the most abundant genera, Aspergillus, Cladosporium, and Penicillium was found in every salt. Many species found in this study have been previously isolated from low water activity environments, including salterns and foods. We conclude that sea salts contain many fungi that have potential to cause food spoilage as well as some that may be mycotoxigenic.

Putting the Mess in Order: Aspergillus welwitschiae (and Not A. niger) Is the Etiological Agent of Sisal Bole Rot Disease in Brazil

“…In addition to having been directly associated with its original substrates and a specific geographic distribution, isolates of A. welwitschiae have also been reported in fresh or dried fruits, such as almonds (Susca et al, 2016 ), Brazil nuts (Massi et al, 2016 ), cashew nuts (Lamboni et al, 2016 ), grapes/raisins, figures, maize, pistachios, and walnuts (Susca et al, 2016 ), as well as in bulbs (modified stems), such as onions (Gherbawy et al, 2015 ) and garlics (Oh et al, 2016 ), and mustard seeds (Hanif et al, 2016 ). Furthermore, Aspergillus welwitschiae has been detected in different environmental substrates, such as outdoor air (Lee et al, 2016 ), indoor dust (Visagie et al, 2014 ), caves (Nováková et al, 2017 ), sea salts (Biango-Daniels and Hodge, 2018 ), and even in clinical specimens from the ear canal in humans, causing otomycoses (Szigeti et al, 2012a , b ), and in human nails, causing onychomycoses (Tsang et al, 2016 ). These records are from distinct climates all over the world (Supplementary Table 3 ).…”

Nature Abhors a Vacuum: Highly Diverse Mechanisms Enable Spoilage Fungi to Disperse, Survive, and Propagate in Commercially Processed and Preserved Foods

“…These fungi may originate in naturally saline environments, like solar salterns, which are often dominated by Aspergillus (Eurotium ) species (Butinar, Zalar, Frisvad, & Gunde‐Cimerman, ; Cantrell, Casillas‐Martínez, & Molina, ; Gunde‐Cimerman & Zalar, 2014; Gunde‐Cimerman, Cerovac, & Zalar, ). Sea salts contain viable fungi and may be a possible source of spoilage inoculum in salted foods, including dry cured meats (Biango‐Daniels & Hodge, ; Butinar, Frisvad, & Gunde‐Cimerman, ; Sonjak, Ličen, Frisvad, & Gunde‐Cimerman, ). Halophilic Wallemia species, unique basidomycetes that can grow in saturated NaCl environments, sometimes spoil baked goods (0.71 to 0.79 A w ), along with ascomycete species of Aspergillus , Penicillium , and Chrysosporium (Gunde‐Cimerman & Zalar, 2014; Guynot, Ramos, Sala, Sanchis, & Marín, ; Jay, Loessner, & Golden, ; Plemenitaš et al., ; Vytrasová, Pribánová, & Marvanová, ; Zajc et al., ).…”

Aspergillus sydowii: Genome Analysis and Characterization of Two Heterologous Expressed, Non-redundant Xylanases

“…Beside its terrestrial appearance in soil, it can grow in the sea due to its salt tolerance ( Hallegraeff et al, 2014 ). In addition, A. sydowii can cause human infections ( Rinaldi, 1983 ) as well as contaminate food ( Piotrowska, 2013 ; Biango-Daniels and Hodge, 2018 ). In marine ecosystems, it causes epizootic infections of sea fan corals ( Geiser et al, 1998 ; Alker et al, 2001 ; Kim and Harvell, 2004 ).…”