Radiation pasteurization of fresh and blanched tropical shrimps

Abstract

The storage life of fresh, peeled and deveined tropical shrimps at 10-12°C is extended to 10-14 and 18-21 days with 0.15 and 0.25 Mrad, respectively, as against spoilage of unirradiated samples within 4 days. Blanching treatment (steaming for 4 min) with or without brine (3.0% NaCl) extends the storage life up to 30 days at 10-12°C. the former retaining the shell-fish flavor. However, the blanched products develop musty odor and slimy texture during storage; subjected to irradiation (0.15 Mrad) these are devoid of undesirable attributes and are acceptable for 60 and 130 days, respectively, at 10-1°C and 2-4°C. Bacterial counts exceeding 10⁸/g and high levels of TMAN and TVBN concur with spoilage of unirradiated shrimps. In contrast, low levels of TMAN and TVBN, despite high TBC, corroborate with high acceptability of radiation processed shrimps. In blanched as well as in blanched and irradiated shrimps TBC, TMAN and TVBN are low. Samples subjected to blanching only have low acceptability as against the improvement in quality by irradiation. These alterations in storage property have been discussed in the light of shifts in microflora.