Acoustic noise of refrigerators promote increased growth rate of the gray mold Botrytis cinerea

Botrytis rot (Botrytis cinerea) is a serious disease of fruit and vegetables around the globe. Botrytis rot is a problem not only in the field, but during storage, transit, and marketing, due to onset of severe rot on ripe produce. Fungal growth is promoted by warm temperatures and high humidity although other factors could play a role. Mechanical stimulation via vibroacoustic energy is known to affect the growth of organisms but is little studied in food safety of crop transportation and storage. We test whether mechanical energy in the form of vibrations and acoustic frequencies from in-store refrigerators and cold-storage units affect the growth rate of botrytis rot. We also test a broad range of single tones (frequency, Hz) and dyads (2-tone chords) from 110 to 25,088 Hz to determine if particular frequencies have differential effects on the growth of botrytis rot. Playback of vibroacoustic recordings of refrigerator units increased the growth of botrytis rot by 13–18%, on average, suggesting that acoustic output from storage units could promote the mold during transport, storage or within grocery stores. Increased fungal growth rate appears to be stimulated by high frequencies, above 5,000 Hz. Additionally, low frequencies below 165 Hz can reduce botrytis rot growth rate suggesting that exposure to very low frequency ranges could be used to control the fungus. Results of this study open new perspectives on how vibroacoustic output from electronic devices and machines may affect food quality and fungal contamination on fruit, flowers, and vegetable produce.