TY - JOUR
T1 - The most heat-resistant conidia observed to date are formed by distinct strains of Paecilomyces variotii
AU - van den Brule, Tom
AU - Punt, Maarten
AU - Teertstra, Wieke
AU - Houbraken, Jos
AU - Wösten, Han
AU - Dijksterhuis, Jan
N1 - This article is protected by copyright. All rights reserved.
PY - 2020/3
Y1 - 2020/3
N2 - Fungi colonize habitats by means of spores. These cells are stress-resistant compared to growing fungal cells. Fungal conidia, asexual spores, formed by cosmopolitan fungal genera like Penicillium, Aspergillus and Peacilomyces are dispersed by air. They are present in places, where food products are stored and as a result, they cause food spoilage. Here, we determined the heterogeneity of heat resistance of conidia between and within strains of Paecilomyces variotii, a spoiler of foods such as margarine, fruit juices, canned fruits and non-carbonized sodas. Out of 108 strains, 31 isolates showed a conidial survival >10% after a 10-min-heat treatment at 59°C. Three strains with different conidial heat resistance were selected for further phenotyping. Conidia of DTO 212-C5 and DTO 032-I3 showed 0.3% and 2.6% survival in the screening, respectively, while survival of DTO 217-A2 conidia was >10%. The decimal reduction times of these strains at 60°C (D60 -value) were 3.7 ± 0.08, 5.5 ± 0.35, and 22.9 ± 2.00 min, respectively. Further in-depth analysis revealed that the three strains showed differences in morphology, spore size distributions, compatible solute compositions and growth under salt stress. Conidia of DTO 217-A2 are the most heat-resistant reported so far. The ecological consequences of this heterogeneity of resistance, including food spoilage, are discussed. This article is protected by copyright. All rights reserved.
AB - Fungi colonize habitats by means of spores. These cells are stress-resistant compared to growing fungal cells. Fungal conidia, asexual spores, formed by cosmopolitan fungal genera like Penicillium, Aspergillus and Peacilomyces are dispersed by air. They are present in places, where food products are stored and as a result, they cause food spoilage. Here, we determined the heterogeneity of heat resistance of conidia between and within strains of Paecilomyces variotii, a spoiler of foods such as margarine, fruit juices, canned fruits and non-carbonized sodas. Out of 108 strains, 31 isolates showed a conidial survival >10% after a 10-min-heat treatment at 59°C. Three strains with different conidial heat resistance were selected for further phenotyping. Conidia of DTO 212-C5 and DTO 032-I3 showed 0.3% and 2.6% survival in the screening, respectively, while survival of DTO 217-A2 conidia was >10%. The decimal reduction times of these strains at 60°C (D60 -value) were 3.7 ± 0.08, 5.5 ± 0.35, and 22.9 ± 2.00 min, respectively. Further in-depth analysis revealed that the three strains showed differences in morphology, spore size distributions, compatible solute compositions and growth under salt stress. Conidia of DTO 217-A2 are the most heat-resistant reported so far. The ecological consequences of this heterogeneity of resistance, including food spoilage, are discussed. This article is protected by copyright. All rights reserved.
U2 - 10.1111/1462-2920.14791
DO - 10.1111/1462-2920.14791
M3 - Article
C2 - 31444981
SN - 1462-2912
VL - 22
SP - 986
EP - 999
JO - Environmental Microbiology
JF - Environmental Microbiology
IS - 3
ER -