Bacterial pathogens in fresh, smoked and salted Iranian fish

Abstract

Salted and smoked fish are traditional products in Iran that are prepared by heavy salting (mixed salting) and heavy salting followed by cold smoking methods, respectively. Twenty eight Alosa kessleri (Caspian anadromous shad) from the Caspian Sea and 39 cultivated Hypophthalmichthys molitrix (silver carp) from two fish farms before and after a smoking process were examined using standard bacterial testing. Forty Liza aurata (Mullet dore) and 20 smoked H. molitrix purchased from a fish market (SMH-m) were also tested. Listeria monocytogenes were greater than 1 × 10 2 g −1 in 2.6% of fresh (not smoked) H. molitrix (FH), 5.1% smoked H. molitrix, 20% SMH-m and 10% salted L. aurata (SAL). Vibrio parahaemolyticus was found in 21.4% fresh A. kessleri, 7.1% smoked A. kessleri, 5% SMH-m, 35% fresh L. aurata (FL) and 50% of SAL. For 7.5% of FL and 2.5% of SAL, V. parahaemolyticus were greater than 1 × 10 2 g −1. Escherichia coli and Salmonella dublin were obtained in 30.8% and 2.6% of FH, respectively. No coliforms and Salmonella spp. were detected in salted fish and smoked fish. Staphylococcus aureus greater than 1 × 10 5 cfu g −1 were obtained in 55% SMH-m and 10% SAL. Consumption of these fish, either raw or undercooked may contribute to foodborne illness in Iran.