Comparison of high-hydrostatic pressure and frozen treatments on raw freshwater clam marinated in soy sauce: Impact on microbiological and organoleptic qualities

The purpose of this study was to compare how the two different methods of food processing, high pressure processing (HPP) under 300–500 MPa for 3 min and freezing, affect the microbiological, chemical, and organoleptic qualities of soy sauce-marinated freshwater clams (Corbicula fluminea) during refrigeration. The aerobic plate count (APC), psychotropic bacteria count (PBC), Salmonella spp., and coliform of high pressure processed soy sauce-marinated clams (HPP marinated-clams) were obviously lower than conventionally frozen soy sauce-marinated clams (frozen marinated-clams), or were not detected. In addition, after all samples' 15-day refrigeration period, HPP was found to significantly inhibit the growth of APC, PBC, Salmonella spp., and coliform, while the microbial counts of frozen marinated-clams increased gradually with time. However, the surface areas, moisture contents, and salt contents of all samples of both HPP marinated-clams and frozen marinated-clams slightly increased during refrigeration. Furthermore, the results of organoleptic analyses exhibited that the storage life of marinated clams can be increased from 9 days under freezing treatment to 15 days under HPP (300 MPa and 500 MPa). Using high-throughput sequencing, HPP treatment significantly changed the microbiota of marinated clam and delayed the spoilage process. Therefore, the study suggests using HPP at least 300 MPa for 3 min to effectively inhibit the microbial growth and significantly extend the storage life of the samples during the refrigeration period. This is a first study to use HPP technology to replace the traditional freezing technology in the application of raw soy sauce-marinated freshwater clam products, and at the same time, HTS was used to evaluate the changes of microbiota during refrigeration.