Microbiome Status of Cider-Apples, from Orchard to Processing, with a Special Focus on Penicillium expansum Occurrence and Patulin Contamination

Abstract

Patulin is a secondary metabolite produced primarily by the fungus Penicillium expansum, responsible for the blue mold disease on apples. It is found in apple products including apple cider when apple juice is added after fermentation. In the present study, two hundred and twenty-five cider-apples of the variety “Bedan”, cultivated in Brittany in France, were sampled from the orchard during harvesting until the storage step, right before processing. The patulin analysis on these samples reported a low contamination at the orchard and a significantly higher-level of contamination in the cider-apples starting from the transporting bin. The percentage of positive samples increased from 6% to 47% after 12 h in the harvesting bin before transporting and reached 95% after 24 h of transporting, decreasing then to 69% at the end of the storage. Penicillium expansum was quantified on the surface of apples using real-time PCR and was observed to be mostly consistent between the harvest and post-harvest steps. It was detected on average, on the surface of 85% of all sampled apples with a mean value around 2.35 × 106Penicillium expansum DNA/g of apple. Moreover, the changes in the fungal and bacterial epiphytic microbiota in the different steps were studied using a metabarcoding approach. The alpha and beta diversity analysis revealed the presence of unique and more diverse bacterial and fungal communities on the surface of apples picked from the orchard compared to the rest of the sampling steps. Potential indigenous biological control agents were identified on the surface of sampled apples. Future perspective includes developing actions of prevention and control of the contamination by Penicillium expansum during the harvest and along the various critical post-harvest stages before transformation in a sustainable development concern.

Cultivable Skin Mycobiota of Healthy and Diseased Blind Cave Salamander (Proteus anguinus)

“…Clinical signs include lethargy and multifocal hyperemic nodules with visible fungal growth, that is in general progressive and leads to death within 2 weeks ( Taylor et al, 1999 ). Although lethargy was an observed symptom in two olms, both in long term captivity, no zygomycosis was determined and only three fungal species were isolated: human opportunistic pathogen A. jensenii ( Zen Siqueira et al, 2016 ), plant pathogenic psychrotolerant P. expansum ( Al Riachy et al, 2021 ) and soil and plant litter associated saprophytic Trichoderma simmonsii ( Chaverri et al, 2015 ). Similar symptoms can occur in cutaneous and disseminated systemic chromomycosis, and phaeohyphomycosis ( Seyedmousavi et al, 2013 ), caused by different pigmented ascomycetous species of the genera Cladosporium , Exophiala , Fonsecaea , Ochroconis , Phialophora , Rhinocladiella and Scolecobasidium ( Juopperi et al, 2002 ; Seyedmousavi et al, 2013 ), which have been isolated from various wild and captive anurans ( Dhaliwal and Griffiths, 1963 ; Elkan and Philpot, 1973 ; Rush et al, 1974 ; Beneke, 1978 ; Miller et al, 1992 ; Seyedmousavi et al, 2013 ).…”

New Isolated Metschnikowia pulcherrima Strains from Apples for Postharvest Biocontrol of Penicillium expansum and Patulin Accumulation

“…Penicillium expansum is the agent of the blue mold decay considered as the most severe postharvest fungal disease since it causes heavy losses in the transportation and storage and it produces the harmful mycotoxin patulin especially in apple fruit [27]. The use of biocontrol agents could inhibit postharvest fruit pathogens by simple antagonistic interaction.…”

“…Yeasts used in this study, were isolated from the skin of apples of the variety "Bedan", in an orchard situated in Brittany, France [27]. A screening was done with 90 isolated yeasts to evaluate their antifungal potential against Penicillium expansum.…”

The Influence of Long-Term Storage on the Epiphytic Microbiome of Postharvest Apples and on Penicillium expansum Occurrence and Patulin Accumulation

“…Patulin extraction from the apples followed the method outlined by Al Riachy et al, with some adjustments [ 58 ]. Apples were squeezed using a laboratory paddle blender (Stomacher ® 400, Seward, Worthing, UK).…”