Impact of maturation and growth temperature on cell-size distribution, heat-resistance, compatible solute composition and transcription profiles of Penicillium roqueforti conidia. (October 2020)

• Record Type: Journal Article
• Authors: Punt, Maarten; van den Brule, Tom; Teertstra, Wieke R.; Dijksterhuis, Jan; den Besten, Heidy M.W.; Ohm, Robin A.; Wösten, Han A.B.
• Is Part Of: Food research international. Volume 136(2020)
• Publication Date: 2020-10
• Subjects: Fungus -- Spores -- Food spoilage -- Penicillium -- Thermal inactivation -- Heterogeneity; ACES N-(2-acetamido)-2-aminoethanesulfonic acid -- MEA malt extract agar -- D-value decimal reduction time -- HPLC high-pressure liquid chromatography; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2020.109287
• Languages: English
• ISSNs: 0963-9969

Abstract

Graphical abstract: Highlights: Longer cultivation time and higher temperature result in conidia with up to 4-fold higher heat-resistance. Both cultivation time and temperature impact trehalose content in P. roqueforti conidia. 33 genes are upregulated at prolonged cultivation time and increased cultivation temperature. Incubation temperature affects P. roqueforti conidia volume up to 25% Abstract: Penicillium roqueforti is a major cause of fungal food spoilage. Its conidia are the main dispersal structures of this fungus and therefore the main cause of food contamination. These stress resistant asexual spores can be killed by preservation methods such as heat treatment. Here, the effects of cultivation time and temperature on thermal resistance of P. roqueforti conidia were studied. To this end, cultures were grown for 3, 5, 7 and 10 days at 25 °C or for 7 days at 15, 25 and 30 °C. Conidia of 3- and 10-day-old cultures that had been grown at 25 °C had D 56 -values of 1.99 ± 0.15 min and 5.31 ± 1.04 min, respectively. The effect of cultivation temperature was most pronounced between P. roqueforti conidia cultured for 7 days at 15 °C and 30 °C, where D56 -values of 1.12 ± 0.05 min and 4.19 ± 0.11 min were found, respectively. Notably, D56 -values were not higher when increasing both cultivation time and temperature by growing for 10 days at 30 °C. A correlation was found between heat resistance of conidia and levels of trehalose and arabitol, while this was not found for glycerol, mannitol and erythritol. RNA-sequencing showed that the expression profiles of conidia of 3- to 10-day-old cultures that had been grown at 25 °C were distinct from conidia that had been formed at 15 °C and 30 °C for 7 days. Only 33 genes were upregulated at both prolonged incubation time and increased growth temperature. Their encoded proteins as well as trehalose and arabitol may form the core of heat resistance of P. roqueforti conidia.