## 1 Introduction  
Louquat (_Eriobotryu japonica_) is widely cultivated in the subtropical regions of southern China, Japan, northern India, Israel, and the Mediterranean. Loquat fruits are highly perishable products, and generally can only keep fresh for 2 to 3 days at room temperature. Fruit provides an ideal substrate for the growth of pathogen microorganisms after harvest, such as the wound-invading fungi _Botrytis_ spp., _Monilinia_ spp. [1], _Penicillium expansum_, _Botrytis cinerea_, and _Colletotrichum acattatum_ on apple [2], and _Penicillium digitatum_ and _Penicillium italicum_ on citrus [3]. Loquat fruit is susceptible to mechanical injury and microbial decay, which limits its storage period and marketing life. Postharvest diseases cause considerable economic losses to harvested fruits and vegetables during transportation and storage. Synthetic fungicides are primarily used to control postharvest decay. However, the recent trend is shifting toward safer and more eco-friendly alternatives for the control of postharvest decay. Among various biological approaches, the application of antagonistic microorganisms is becoming more and more popular throughout the world. Several postharvest diseases can now be controlled by microbial antagonists [4]. Although some mechanisms by which microbial antagonists suppress the postharvest diseases are still unknown, competition for nutrients and space is the most widely accepted mode of action [5]. In addition, the production of antibiotics [6], direct parasitism, and possibly induced resistance [7] in the harvested commodity are also probable mechanisms. Microbial antagonists are applied either before or after harvest, but postharvest applications are more effective than preharvest applications [4]. The release of volatile organic compounds (VOCs) by some soil microbes has been reported to promote plant growth [8], display nematicidal activity [9], and induce systemic resistance in crops [10]. Headspace solid-phase microextraction (HS-SPME), a promising method for extraction of volatile compounds, is possible to identify characteristic VOCs for any bacterial species. The VOCs identified belong mainly to the alcohol group (ethanol, 3-methylbutan-1-ol, 2-methylbutan-1-ol, 2-phenylethanol), to the esters (ethyl acetate, ethyl octanoate) [11], and aldehydes (2-methylhex-2-enal, 2-isopropyl-5-methylhex-2-enal) [12]. _Bacillus_ has been proven to produce nonvolatile or volatile substances which have inhibitory effects against _Fusarium oxysporum_[13; 14], _Botryosphaeria berengeriana_[15], _Trichoderma_ sp. [16], _Colletotrichum gloeosporoides_[17; 18], and _Penicillium_ sp. [19]. Volatile organic compounds responsible for the antifungal effect include 2,3,6-trimethylphenol, nonan-2-one, decan-2-one, dodecan-2-one, undecan-2-one, 2-methylpyrazine, etc. and effective protection against fungi is often not the action of one substance but a combination of many compounds. However, there are few broad-spectrum antifungal strains against postharvest diseases, not to mention relevant volatile data applied to loquat fruit. The storage of loquat fruit is very difficult and there are few biological control methods. New _Bacillus_ strains BCN2 and BCN10 were reported for the first time to show the excellent biocontrol effects on the spoilage of loquat fruits. The combined application of the two strains can provide the widest antifungal spectrum in loquat preservation. Volatile organic compounds produced by _Bacillus methylotrophicus_ BCN2 and _Bacillus thuringiensis_ BCN10 are key ingredients against postharvest pathogens, and the non-contact application of spore-forming bacteria also provides a guarantee for food safety and further commercial promotion.