Exploring the Effects of 528-Hz Sound Frequency on Yogurt Quality and Microbial Viability During Storage

The 528-Hz sound frequency is known to be one of the “Solfeggio frequencies” that are believed to have positive effects on living organisms. This study seeks to explore how 528 Hz influences the physical and chemical characteristics as well as the microbial viability of yogurt, a dairy product containing active cell cultures. During a 31-day storage period, various yogurt samples were subjected to either 528-Hz sound, city noise (a continuous day-time recording from a crowded urban area), or kept under standard conditions for comparison. The main goal was to evaluate changes in pH levels, moisture separation (syneresis), sensory properties like taste and texture, consistency, flow behavior, and the survival of Streptococcus thermophilus bacteria. The findings indicated that the pH values of yogurt exposed to 528 Hz remained relatively stable throughout the storage period, only experiencing a slight decrease from 4.33 to 4.25 by Day 31. In contrast, the control group showed a more pronounced reduction from 4.33 to 4.10 during the same period. Assessment of taste perception, texture quality, and aroma intensity revealed higher scores for samples treated with 528 Hz compared to those in the control group. S. thermophilus counts, for all samples, initially experienced a decline but showed recovery by Day 31, with final counts ranging from approximately 4.42 × 10⁷ to about 4.7 × 10⁷ CFU/mL. To sum up, the use of the 528-Hz sound frequency had a beneficial impact on the sensory characteristics and pH stability of yogurt while not causing notable changes in syneresis, texture, or microbial viability. These results suggest that employing sound treatments could potentially improve certain quality aspects of yogurt over time, but further investigation is needed to confirm these effects.