Nowadays, pasteurization is widely used in the fruit juice and beverage industry for the inactivation of spoilage bacteria and pathogens (Sourri et al., 2022). However, as acidothermophilic spore-forming bacteria, Alicyclobacillus acidoterrestris could survive the pasteurization processes and germinate at room temperature (Pornpukdeewattana et al., 2020). In this process, the bacteria can lead to the spoilage of beverages and metabolize guaiacol, 2,6-dibromophenol and 2,6-dichlorophenol, resulting in a smoky, medicinal and antiseptic off-odor (Aguirre et al., 2014; Söbeli et al., 2021). Especially, as an indicator of spoilage, guaiacol can be detected with the concentration of 2 μg/L, which is produced by A. acidoterrestris cells at 104–105 CFU/mL (Cai et al., 2019). A. acidoterrestris-related problems are relatively common and have resulted in significant economic losses for juice processing companies (Wang et al., 2022b). Therefore, new methods are urgently needed to control the contamination of A. acidoterrestris.

Conventional thermal pasteurization and sterilization are widely used for the inactivation of microorganism in food products. However, these thermal methods adversely affect the sensory qualities and nutritional values of processed foods (Zhang et al., 2021). Compared with thermal treatments, non-thermal methods can increase the retention of flavors, colors and nutrient compositions. The growing demand for high-quality food has led to the development of non-thermal processing technologies. Refers to the use of instantaneous high intensity energy and wide spectrum (200 to 1100 nm), pulsed light (PL) has been widely applied for the inactivation of microorganisms (Wang et al., 2022a).

PL is a non-thermal sterilization technology for the preservation of foods. As a novel technique, its utilization fits the current requirements for safety, high quality and low environmental impact. During PL application, the energy is stored in a high-power capacitor and released over a short period of time, producing several high energy flashes per second, thus increasing the instantaneous energy intensity and contributing to the deactivation of microbial cells. The lethal effect of PL on microorganisms is mostly attributed to the photochemical, photothermal, and photophysical effects (Chen et al., 2021; Kaya et al., 2020). The decontamination competence of PL has been proven in a lot of studies on different food matrices. In some previous researches, PL treatment has been revealed to be effective in reducing microbial contamination in the treatment of fresh fruits, vegetables, liquid food and packaging material (Chen et al., 2015; Mandal and Pratap-Singh, 2021). PL treatment can also be used in combination with other techniques (ultrasound, thermo sonication, mild heating, etc.) to enhance their inactivation impacts on food contamination (Ferrario et al., 2015; Kaya et al., 2020).

The objectives of this study were: (a) to evaluate the influence of different factors on the inactivation of A. acidoterrestris in apple juice, (b) to investigate the possible mechanism of PL against A. acidoterrestris vegetative cells and spores, (c) to examine the effects of PL treatment on the qualities of apple juice. This study will provide a theoretical basis for the inactivation of A. acidoterrestris vegetative cells and spores in apple juice.