Spoilage potential of Bacillus isolates from preserved furu rou (sufu-braised streaky pork) prepared dish and their impact on volatile organic compounds during storage

Furu rou (sufu-braised streaky pork) is a renowned traditional Chinese dish linked to the "Manchu-Han Imperial Feast". Its prepared product is often prone to spoilage by heat-resistant Bacillus spores during storage. This study isolated spoilage bacteria from furu rou stored at 4 °C for 40 days; Bacillus amyloliquefaciens JY-4 and Bacillus subtilis JY-71 exhibited significant proteolytic and lipolytic capabilities. Electronic nose (E-nose), electronic tongue (E-tongue), and gas chromatography-mass spectrometry (GC-MS) analyses revealed that B. subtilis JY-71 metabolized to produce large amounts of sulfur-containing compounds and nitrogen oxides, causing putrid odors. Additionally, a total of 98 volatile organic compounds (VOCs) were identified in the Bacillus spores-inoculated samples and the control group; the differences in their compositions indicated that Bacillus might promote the conversion of aromatic compounds such as esters and alcohols into off-odor characteristic compounds including aldehydes, acids, and hydrazines (e.g., hexanal, trans-13-octadecenoic acid, and 5-furfurylhydantoin). Correlation analysis showed that volatile flavor substances such as butanediol and acetoin played important roles in driving the taste deterioration of furu rou . This study characterizes the spoilage behavior of specific Bacillus species in furu rou , providing a theoretical basis for formulating effective quality control strategies. • Bacillus strains were isolated and identified from furu rou prepared dish. • The spoilage potential was verified bidirectionally from both in vitro and in situ. • Bacillus significantly affected the evolution of VOCs in furu rou during storage. • Bacillus is a significant contributor to furu rou spoilage. • There was a significant correlation between the electronic tongue and key VOCs.