1. Scallop Powder Containing Ice for Fresh Fish Preservation: A New-fledged View about Food Safety of Bangladesh
Sunzid Ahmed1,Md. Tanvir Islam1*, Sharmin Zaman2, Arafat-Al-Mamun2,Nahinur Rahman Akand2 and Md. Latiful Bari2
1Department of Microbiology, Jessore University of Science & Technology, Jessore 7408, Bangladesh
2Food Analysis and Research Laboratory, Center for Advanced Research in Sciences, University of Dhaka, Dhaka-1000, Bangladesh.
*Corresponding author: Assistant Professor, Dept. of Microbiology, Jessore University of Science & Technology, Jessore- 7408, Bangladesh.
ABSTRACT
Dead fishes become an optimum source of nutrition for microorganisms to be multiplied and thus the fishes start to be spoiled. So fish preservation by health-hazard less preservatives is mandatory if we want to lift up the shelf life keeping them away of microorganisms. This present study was designed to evaluate the effectiveness of 0.01% scallop powder (SP) solution, 3% hydrogen peroxide (H2O2) solution, 200ppm chlorine (Cl2) water, and 4% sodium chloride (NaCl) solution alone or in combination with ice made of 0.01% SP for extending the shelf life of a sweet water fish Rohu (Labeo rohita). It was found that washing fishes with those above mentioned sanitizers followed by normal tap water made ice storage at room temperature could retain both of the microbiological quality and sensory parameters acceptable and good for about a week. Fishes of control group showed similarity with the phenomenon stated earlier. But after a periodic examination we observed that, fishes got normal tap water wash followed by 0.01% SP containing ice storage was physically good to accept till 16 days, when bacterial load was decreasing continuously from the initial count. It was also found that, for a certain period of time 0.01% SP containing ice melted water (to be discarded) contains comparatively smaller load of fish surface bacteria. To maintain optimum preservation efficacy, change of ice was done routinely. Inoculation study with rifampicin resistant Escherichia coli showed that, preservation in refrigerator after washing fishes with 0.01% SP water was not as fruitful as it was out of refrigerator with 0.01% SP mixed ice. So it is 0.01% scallop powder containing ice, effective enough for fish preservation comparing with the other sanitizers used here.
Key Words: Fish preservation, sweet water fish, scallop powder, melted ice, spiked study.
1. Introduction
The fish Rohu (Labeo rohita) was used as the experimental organism in this study is one of the endemic species available in Bangladesh. With the ever growing world population and the necessity to store and transport the food from one place to another, food preservation becomes mandatory in order to increase its shelf life and keep its nutritional value, texture and flavor good in quality. In this study, 3% H2O2 solution and 200ppm of chlorine water were used, which are permitted by FDA as commonly used sanitizers to control microorganisms in food and food products. In addition, 4% NaCl was used in the belief that microorganisms living in sweet water fish could be inhibited by this concentration and 0.01% SP was used because of its effectiveness against many foodborne pathogens in different freshly obtained food items before. The main component of scallop shells is CaCO3, whose antibacterial activity is due to the generation of CaO after heat treatment.
3. Results & Discussions
Figure 4: Physical Conditions of Fishes of Control Group
Figure 5: Total Aerobic Bacterial Count of Control Group
Figure 6: Physical Conditions of Fishes Stored Under 0.01% SP Containing Ice
Figure 7: Total Aerobic Bacterial Count of Fishes Stored Under 0.01% SP Containing Ice
Figure 8: Physical Conditions of Fishes Washed with 0.01% SP Solution
Figure 9: Total Aerobic Bacterial Count of Fishes Washed with 0.01% SP Solution
Figure 10: Physical Conditions of Fishes Dipped with 4% NaCl Solution
Figure 11: Total Aerobic Bacterial Count of Fishes Dipped with 4% NaCl Solution
Figure 12: Physical Conditions of Fishes Dipped with 200 ppm Chlorine Water
Figure 13: Total Aerobic Bacterial Count of Fishes Dipped with 200 ppm Chlorine Water
Figure 14: Physical Conditions of Fishes Dipped with 3% H2O2 Solution
Figure 15: Total Aerobic Bacterial Count of Fishes Dipped with 3% H2O2 Solution
Figure 16: Graphical Presentation of Ice Melted Water Microbiological Analysis
Figure 17: Graphical Presentation of Inoculation Study Microbiological Analysis
Dissolved SP in water increases its pH to around When SP containing ice melts, the alkaline water washes the fish surface and eliminates the survival of spoilage causing microorganisms. The alkaline water also inhibits the functioning of enzymes responsible for fish deterioration. The discarded water emitting from the SP mixed ice containing fish box will contain very low level of microorganisms if we maintain proper icing method, therefore our environment will stay contamination free. Inoculation study results suggest that, using sanitizers before refrigeration may not bring any significant benefit in fish preservation.
2.1. Materials & Methods
In this work sanitizers were used in some specific combinations to treat fishes:
Fishes were dipped in distilled water (DW) for 5 minutes and kept under DW made ice.
Fishes were stored in ice made of 0.01% SP water after dipping in tap water.
Dipping Fishes in 0.01% sp water for 5 minutes and storing under ordinary ice.
Ordinary ice storage of fishes after dipping in 4% NaCl solution for 5 minutes.
Sanitizing fishes with 3% H2O2 solution for 5 minutes and storing under ordinary ice.
Washing fishes in 200ppm Cl2 water for 5 minutes and keeping under ordinary ice.
2.2. Icing Procedure
2.3. Microbiological Analysis of Fish Flesh
2.4. Sensory Evaluation
Sensory parameters (skin color, flesh firmness, slime color, condition of eye and gill, belly cavity condition, color of blood, and smell) of fish were evaluated routinely according to the Quality Index Method (QIM).
2.5. Inoculation Study
In inoculation study isolation of rifampicin resistant Escherichia coli from fish surface was performed on some specific days during refrigeration. The isolation was done using rifampicin supplemented agar media.
4. Conclusion
So its 0.01% scallop powder containing ice can preserve fishes of specific origin at room temperature in good condition for over two weeks by keeping its microbiological, physical and organoleptic condition acceptable and good for consumption. Maintaining the proper icing methods followed in this experiment, 0.01% scallop powder containing ice is useful for local fish preservation and can be replaced the use of formalin or other harmful preservatives practices in Bangladesh.
Acknowledgement
We thank Food Analysis and Research Laboratory, Center for Advanced Research in Sciences, University of Dhaka, for providing technical supports. The work was financed by Ministry of Science & Technology.