# Antimicrobial Efficacy of Edible Mushroom Extracts: Assessment of Fungal Resistance
## 1 Introduction
camphoratus_ ethanolic extracts possess broad-spectrum bioactivities including (a) anti-inflammatory/ameliorative effects to prevent diabetes-induced male reproductive dysfunction [17]; (b) synergistic adjuvant effects to downregulate cancer stem genes and to enhance the antitumor ability of 5-fluorouracil [18]; and (c) inhibitory effects on lung tumor growth and metastasis by inducing apoptosis and inhibiting the \"Signal Transducer and Activator of Transcription 3 (STAT3)\" signaling pathway [19]. To date, over seventy compounds in _T. camphonatus_ have been characterized as exhibiting hepatoprotective, antihypertensive, antihyperlipidemic, anti-inflammatory, antioxidant, antitumor, and immunomodulatory activities [15; 20]. The basidiomycete _Agaricus blazei_ has also been used for medicinal purposes. Recent studies have determined that _A. blazei_ contained hydrophilic small molecules such as phenolics, lipophilic small molecules such as agarol, and macromolecules such as \(\beta\)-glucans, which exhibited: (a) immunomodulation, cell signaling, anti-inflammatory, antidiabetic, antiparasitic, and antimicrobial activities; (b) antimutagenic, anticancer/tumor-growth inhibitory effects; and (c) hepatoprotection activity against chemical or viral infection [21]. In addition, several studies have reported the antioxidant potential of _A. blazei_. The _A. blazei_ ethyl acetate extract exhibited hepatic antioxidant activity, whereby it helped the recovery of impaired pancreatic tissues [22]. _A. blazei_ in the dried and powdered mycelial form also presented antigenotoxic and hydroxyl radical (OH) scavenging activities [23], while the _A. blazei_ methanolic extract showedantioxidant/anti-inflammatory properties in Parkinsonic mice [24]. Other investigators have reported that an _A. blazei_ hot water extract inhibited the proliferation of pancreatic cancer cells via the induction of G0/G1 cell cycle arrest and caspase-dependent apoptosis [25], and that _A. blazei_ polysaccharides inhibited schistome infection as well as improved pathological effects associated with granulomas [26]. The polypore fungi _Ganoderma_ spp. are also one of the most studied edible mushrooms. They possess active ingredients such as polysaccharides, mono-/tri-terpenoids, ganoderic acids, alkaloids, fatty acids, organic germanium, ergosterol, mannitol, and other bioactive compounds [27; 28; 29; 30]. _Ganoderma_ spp. ingredients exerted: (a) modulation of neurogenesis, amelioration of Alzheimer's disease, protection on neural cells in stroke injury, treatment of diabetes and insulin resistance [29; 30]; (b) antifibrotic activity or inhibition of pancreatic lipase or T-type voltage-gated calcium channels [27]; and (c) antiviral, antibacterial, and antifungal activities [28]. Of note, certain immunomodulatory proteins or polysaccharides identified in _Ganoderma_ spp. have been used in cosmetics for their antioxidant and antibacterial activities, inhibition of melanin, and regulation of inflammatory mediators [31]. _Ganoderma_ spp. also appear useful for cancer treatment through the regulation of the immune system [32]. However, reports on the risk assessment of mushroom extracts per se or the purified mushroom ingredients toward food preservation are still very scarce. Except for the limited studies on the toxicity mushrooms may exert [33; 34], risks such as the development of microbial resistance to mushroom derivatives have not been fully investigated. In this study, the antimicrobial activity of alcoholic and water extracts from _T. camphoratus_, _A. blaze_, and _Ganoderma lucidum_ powders were investigated against foodborne fungal and bacterial contaminants in defined medium or commercial food matrices (apple and grape juice agar). The efficacy as well as the resistance risks of mushroom extracts were examined by including the antioxidant signaling mutants of the mycotoxin (patulin)-producing _Penicillium expansum_ and the pathogenic _Aspergillus fumigatus_ to monitor their resistance to the mushroom extracts.