TH2682Y - The process of producing hygienic shellfish. - Google Patents

Abstract

The hygienic shellfish production process involves cleaning shellfish to meet hygienic standards, ensuring safety for consumption, and effectively reducing microbial contamination. This is achieved by rearing the shellfish in treated seawater that has been sterilized to eliminate harmful microorganisms. Naturally, bivalve mollusks draw in clean water, which washes away microorganisms and contaminants from their intestinal walls. These microorganisms are then destroyed by the high intensity of ultraviolet (UV) light from the constantly circulating water. The challenge lies in enticing the shellfish to open their mouths to allow them to draw in the clean water. The technique involves creating a familiar environment for the shellfish, controlling salinity, temperature, and water circulation. In short, it creates a clean and safe environment for the shellfish to naturally clean themselves. Furthermore, this process opens opportunities for Thai agricultural products to be exported to countries with sanitary trade barriers.

Claims (5)

1. The process of producing hygienic shellfish consists of the following steps: 1. The oysters of the correct size are passed through a shell-scrubbing machine with bristles to clean off dirt and mud clinging to the shells. 2. Release the cleaned oysters into the holding pond. The water in the pond is obtained from a natural water source near the oyster farming area and undergoes microbial sterilization in a treatment pond before being released into the pond. The process is as follows: 2.1 Filtration through a sand filter to ensure clarity. 2.2 Sterilization of the water using ultraviolet light by circulating the water through a panel of 50 UV lamps with a wavelength of 253.7 nanometers and a light intensity of at least 10 foot-candles. The UV lamps are in direct contact with the water, and a leakage protection system is in place between each lamp to ensure clean water. 2.3 Water quality is checked before being released into the holding pond to meet the following standards: 2.3.1 The optimal temperature for oyster self-cleaning is 20°–25°C. 2.3.2 The water turbidity must be clear or not exceed 20 JTU., which can be achieved by using synthetic fiber sheets. 2.3.2 High frequency and a sand layer 1.20 m thick. 2.3.3 The optimal water pH is 7.0-8.4. 2.3.4 Salinity 18-30 PPT or 20% salinity at the rearing source (formula). 2.3.5 Oxygen content in the water used: approximately 5-15 mg/L. 3. Release the treated water into the rearing pond, where it circulates continuously at a flow rate of 2-3 cycles per hour. A suitably sized water pump with a flow rate of approximately 200 cubic meters per hour is used, along with a well-designed gate valve system to maintain a constant water flow rate. The pond floor is designed with a slight slope of about 5 degrees to save energy in water filtration and pumping, as it utilizes the principle of gravity flow. Furthermore, the gate valve system allows for adjustment of the water circulation rate to suit the type of shellfish. 4. Water circulates in a closed system between the rearing ponds and the treatment ponds, ensuring that the water continuously passes through the UV microbial sterilization system. 5. Shellfish in the rearing ponds have an excellent self-cleaning ability. They suck in and expel clean water, gradually washing away microorganisms clinging to the intestinal walls until they meet consumption standards. This process takes 6-12 hours, depending on the type of shellfish, size, and the amount of microorganisms accumulated in their intestines. Through this self-cleaning, mud and silt inside the shell are gradually removed, resulting in shellfish that are clean both inside and out.