How to Control Salmonella in Fish Meal

Special care must be taken to prevent Salmonella infection during fishmeal production. As long as the temperature exceeds 80°C, the bacterial organic structure is destroyed during cooking and pressing, but poor hygiene conditions can lead to re-infection of fishmeal. Can lead to re-infection of fishmeal. It must be emphasized that despite the high air temperature in the dryer, the fish feed in the dryer may not be raised to a high enough temperature for long enough to destroy Salmonella. To minimize risk, manufacturers should observe the following precautions:

a. The land surrounding the factory should be properly managed and regularly maintained to prevent the entry of rodents, birds, flies and other insects. Especially in areas where fish feed is processed and fish meal is stored, very strict controls have to be exercised in this regard.

b. Fans and other vents in factories and warehouses should be protected with insect-proof and rodent-proof nets.

c. In order to keep the products dry, the warehouse should have concrete floors, leak-proof walls and roofs, and if necessary, set up roof insulation to prevent condensation and dripping of water vapor. The conveyor belt should have a cover.

d. Sidewalks leading to storage areas should be kept clean and foot pads should be provided with disinfectant. Disinfectant ingredients containing phenolic or quaternary ammonium compounds should be available to staff at the entrance to the storage area.

e. One measure that can be adopted is to implement wet and dry partitions in the plant and reduce the frequency of people and equipment passing between different areas.

f. A suitable plant cleaning program is very necessary. Empty storage bins and unloading areas should be cleaned as soon as possible after use. Processing machinery should be cleaned regularly with high pressure hot water and detergent solutions after use.

g. The protein water concentration and oil-water separation unit must be preheated to 93°C or higher before adding to the compressed fish cakes. After the machine has been running for about forty-five minutes and has been preheated to normal operating temperature, all compressed fish cakes must be returned to the cooker to be re-cooked and re-pressed to prevent re-contamination.

However, if Salmonella is detected in fishmeal, the contaminated batch must be sterilized. For example, in special units, fish meal is heated with fresh steam at high temperatures around 90°C for 10 to 15 minutes and then re-dried. Alternatively, insecticides such as formic acid and propionic acid can be used to treat infected fishmeal. Nonetheless, the reprocessing process incurs a lot of extra cost, which is much more economical if effective precautions are taken.