Acoustical experiment of yogurt fermentation process

Area of Science:

• Food Science
• Acoustics
• Biotechnology

Background:

• Hygienic management is crucial in food manufacturing, often validated by certifications like Hazard Analysis and Critical Control Point (HACCP).
• Effective food monitoring systems are essential for ensuring product safety and quality.
• Acoustical measurements offer non-contact and non-destructive advantages for food monitoring.

Purpose of the Study:

• To investigate the use of acoustic transducers for monitoring the lactic fermentation process in yogurt production.
• To correlate acoustic wave properties with temperature and phase changes during fermentation.
• To evaluate the potential of this acoustic method for hygienic, non-invasive food monitoring.

Main Methods:

• Acoustic transducers were used to monitor phase retardation of acoustic waves during yogurt fermentation.
• Temperature changes were simultaneously measured using thermocouples.
• The study involved inserting a sensor into milk inoculated with lactic acid bacteria at 19°C, using a 3.7 MHz frequency.

Main Results:

• The acoustic method detected temperature changes due to fermentation heat, indicated by phase difference shifts.
• A gradient change in temperature was observed, which ceased despite continued temperature change, correlating with the liquid-to-gel phase transition.
• The system successfully monitored the fermentation from milk to Caspian Sea yogurt.

Conclusions:

• Acoustic measurements can effectively monitor the physical and thermal changes during lactic fermentation.
• The non-contact and non-destructive nature of this acoustic sensing method minimizes the risk of food contamination.
• This technology holds significant potential for improving hygienization and monitoring in the food manufacturing industry.