Development of UV-depurator for live blood cockle (Anadara granosa)

Blood cockle (Anadara granosa) is a favourite marine food for Thai people. The microbial organisms and mud become the important natural comtaminants that cause diarrheal diseases and dirty appearance. Until now there has not been cockle depuration technic in commercial sector in Thailand. This project aims to develope the live blood cockle UV-depurator for seafood restuarant to depurate the blood cockle before selling to the customers. Operating system and every component of the UV-depurator were designed to suite for seafood restuarant and each component had been improved to operating conformably for the cockle depuration system. By using the designed UV-depurator, optimizing level of 3 factors on developing the cockle depuration process: cockle stock density, salinity and recycle flow rate of sea water was experimenting. Microbial safety, cleanliness and freshness of 0, 6, 12, 24, 36 hours depurated cockle were examined as a quality response index. The results showed that the using stock density of 53.42 kgs/square m, 25 ppt salinity and 20 l/min flow rate were appropriated for depurating cockle to acceptable quality. The aerobic plate count decreased from 2.07x10*[5) to 3.07x10*[3) cfu/g. Besides the coliforms, faecal coliforms and E. coli were not detected. Cleanliness score increased from 1.97-2.35 to 4.37-4.40 which score 5 was the highest score. Freshness of depurated cockle was not different from the undepurated cockle (p0.05) by using only 12 hours for depuration. The developed UV-depurator and its specification: feature, size, method of operating, method of maintenance and price were used for presentation and demonstration in one-day workshop seminar in order to testing adoption from the seafood restuarant user. The results showed that there were 19 participants from 30 target participants to attend this workshop seminar and everyone adopted the efficiency of UV-depurator including its feature, size, method of operating and maintenance. But the refusal of using this instrument in the restuarant due to the risk of investment and it was not needed to depurate cockle at the present time.