Design of a hydrodynamic cavitation system for the extraction and detection of Escherichia coli (O157:H7) from ground beef

Pathogen detection in food is essential for mitigating a community's adverse health and economic impacts. Pathogen extraction and release from food matrices is a bottleneck for current detection systems. Homogenization via stomaching is the best available method for pathogen extraction from meat. However, the recovery of pathogens is limited. This paper presents the benefit of adding seven minutes of cavitation to the stand-alone stomaching method for the homogenization of ground beef and subsequent downstream detection of E. coli O157:H7 in spiked ground beef. To the best of our knowledge, this is the first instance of the utilization of stomaching followed by cavitation for the extraction of pathogens from food matrices. In this study, the homogenization of ground beef is characterized using particle size measurements. Results show that homogenization of the ground beef increases as cavitation intensity increases, leading to an enhanced release of E. coli O157:H7 compared to stand-alone stomaching. However, much higher intensity cavitation (cavitation number = 0.84) would damage E. coli O157:H7, leading to a 20.5% reduction in the viable E. coli O157:H7, adversely affecting downstream detection. Therefore, cavitation parameters were optimized to maximize the release of E. coli O157:H7 from ground beef and concomitantly minimize the damage to the pathogen. The addition of seven-minute cavitation to stomaching was 74 % more effective than the current gold standard, stand-alone stomaching for detecting E. coli O157:H7 from ground beef. The work presented here has substantial implications for extracting various pathogens from different types of food.