Safety and Quality Aspects in Dry Fisheries Sector of Chalan Beel, Bangladesh: Improve Techniques, Product Promote and Awareness Development

Abstract

The study was conducted with a view to evaluating safety and quality aspects of dried fish prepared from traditional (trad.) technique implying conventional practices in open condition and experimental (exp.) method with setup of different drying techniques for five fish species (Channa punctatus, Mystus vittatus, Channa striatus, Wallago Attu and Puntius sp.) from January 2015 to December 2017 in five fish drying areas of Chalan Beel under the upazila of four districts namely Singra Upazila of Natore; Atrai of Naogoan; Chatmohor and Vangura of Pabna and Tarash Upazila of Sirajganj district in northern area of Bangladesh. Different low cost drying techniques, viz. Black Polythene Sheet (BPS), White Tin Sheet (WTS), Black Tin Sheet (BTS), White Plastic Tunnel (WPT), Hanging Box (HB) and Traditional Method (TRD) were used. Among all the techniques WPT was found to be most suitable with the highest average temperature of 38.14 C whereas the lowest (23.98°C) was in HB; relative humidity ranged from 33.20 (WPT) to 64% (HB); average drying time varied from 25.20 (WPT) to 35.0 hour (BPS). In nutritional composition, the highest protein content was 79.71 in C. striatus (exp.) and the lowest was 50.33% in Puntius sp. (trad.); highest fat content was 18.50 in Puntius sp. (exp.) and the lowest was 3.12 % in C. striatus (trad.); highest moisture level was 20.90 in C. striatus (trad.) and the lowest was 9.21 % in Puntius sp. (exp.); and the highest ash content was 29.9 in Puntius sp. (trad.) and lowest was 14.97% in C. punctatus (trad.). In case of minerals, the highest level of iron was 15.2 in M vittatus (exp.) and lowest was 3.57 mg/l00g in C. striatus (exp); the highest amount of calcium was 190.60 in M vittatus (trad.) and lowest was 20.83 mg/1 00g in C. striatus (exp.); the highest potassium content was 90.47 in W attu (trad.) and lowest was 70.80 mg/1 00g in C. striatus (exp.); and phosphorous content ranged from 229.78(C. stria/us) to 535.45 mg/l00g (M vittatus) and 261.62 (C. punctatus) to 450.08 mg/l00g (Puntius sp.) in traditional and experimental sample respectively. In terms of heavy metals, the sequence of accumulation was Copper (Cu)> Lead (Pb)> Chromium (Cr)> Cadmium (Cd). In case of hygiene indicator bacteria, total coliforms were found in all trad. samples with highest count of 4.5 x 103 cfu/g in Puntius sp. and in exp. samples total coliforms were detected only in W Attu (Ix 102) and C striatus (Ix 102 cfu/g). Fecal coliforms were found in C striatus (1.5xl02), W Attu (2xl02) and Puntius sp. (2.5x 102 cfu/g) only in trad. sample. In terms of pesticidal residues Chlorpyrifos pesticide was detected in W Attu, C. punctatus and C. striatus. In shelf-life assessment, after 8th month of storage the sensory score ranged from 1.88 (Puntius sp.) to 5.42 (C. punctatus) and 4.5 (Puntius sp.) to 7.25 (C. punctatus) in traditional and experimental samples respectively. The highest Total Volatile Base Nitrogen (TVB-N) value was 115.5 in C. striatus (trad.) and lowest was 65.45 mg/1 00g in Puntius sp.(exp.); the highest Peroxide Value (PV) was 45.50 in C. striatus (trad.) and lowest was 18.5mEq/kg in M vittatus (exp.); the highest pH was 8.05 in C. striatus (trad.) and lowest was 5.75 in Pintius sp.(trad.); and the highest Standard Plate Count (SPC) was 6.19 in C. striatus (trad.) and the lowest was 4. 71 LogCFU/g in M vittatus (exp.). In case of sensory evaluation regarding various packaging methods after 4th and 8th month of storage, vacuum package demonstrated comparatively satisfactory performance obtaining better sensory score varying from 7.05 (Puntius sp.) to 8.20 (C. punctatus) and 4.80 (W Attu) to 7.10 (C. punctatus) respectively, followed by nitrogen, normal sealed air pack and unsealed or open package having relatively lower score. In term of status of awareness regarding harmful effects of pesticides, 51.7% of the respondents were involved in abuse. Besides, 7% of them used tube well water and 68.3% were found to be habituated to washing hands with soap or ash before drying operation. Most of the (55%) drying yards had no toilet facility. In this scenario regarding educational level of the dried fish processors, most of them (49%) were primary qualified. In addition, majority (77%) of the processors were engaged in borrowing capital from commission agents (Arotders). Income of dried fish processors varied between 5001 to 10000 BDT per year.