Bacteriological Quality of Aquacultured Freshwater Fish Portions in Prepackaged Trays Stored at 3°C

Abstract

Fresh trout fillets and salmon slices packed in trays were obtained from two multinational chain supermarkets and evaluated for freshness and bacteriological quality immediately after packaging and during storage at 3 degrees C. Initial aerobic counts at 30 and 25 degrees C were significantly (P < 0.05) lower in trout fillets (5.27 +/- 0.57 and 4.87 +/- 0.80 log CFU/g, respectively) than in salmon slices, where levels in excess of 6 log CFU/g were found. In both products, initial Enterobacteriaceae counts were slightly higher than 3 log CFU/g and increased significantly during shelf life by approximately 3 log CFU/g. Most of the enterobacteria were identified as Citrobacter freundii, Hafnia alvei, and Enterobacter cloacae. On day 0, most probable number (MPN) counts of total and fecal coliforms were not significantly different, numbers of the latter group being approximately 4 MPN/g. Escherichia coli was only detected when fish was spoiled. Although initial presumptive Staphylococcus aureus counts were approximately 3 log CFU/g, only 4 of 84 selected colonies belonged to this species. Neither Salmonella nor antimicrobial residues were detected in any sample. Ethanol content in salmon slices did not significantly (P > 0.05) increase until they became inedible. Significant correlation (r = +0.72, P < 0.05) was observed between this chemical index and viable counts at 30 degrees C only when salmon slices were inedible. Trout fillets were acceptable for 7 days, and salmon slices showed signs of spoilage after 4 days. Although public health concerns associated with packed trout and salmon appear to be minimal, data on sensory quality, shelf life, and total viable and Enterobacteriaceae counts strongly suggest the need to improve the quality control systems used by European multinational retailers, especially for imported salmon.

Effect of Chilling on Microbiological, Biochemical and Sensory Attributes of Whole Aquacultured Rainbow Trout (Oncorhynchus mykiss Walbaum, 1792)

“…[36]. These values obtained in this study are close to the values reported earlier for aquacultured fresh trout from Spain [37,41], Greece [38,39] and U.K [40]. It is widely accepted that the initial microbial load of fresh water varies depending on water conditions and temperature.…”

Catfish Special Edition: Microbial Quality of Catfish Nuggets

“…In their study on fish fillets, González-Rodríguez et al [8] used the Enterobacteriacea counts as an indicator and stated that when the count exceeded 6 log cfu/g the fish quality was unacceptable. In their study Chytiri et al [11] found that Enterobacteriaceae was a part of the spoilage microflora of filleted trout and reached a level of 5.5 log CFU/ cm 2 when stored on ice.…”

“…Characteristic positive colonies (black with halo) were confirmed to be S. aureus by the API ® Staph and were coagulase positive. Neither isolate produced the classical food poisoning enterotoxin types A, B, C, D or E. In their report surveying 24 lots of freshwater fish, González-Rodríguez et al [8] reported 4 confirmed isolates of S. aureus. They did not determine if these isolates were enterotoxin producers, but did determine that most of the isolates were coagulase-and thermonuclease negative.…”

“…The reported aerobic bacteria counts of finfish fillet products varies, depending if the product was purchased fresh or frozen at local retail establishment, or ordered from the Internet [6][7][8][9]. The International Commission on Microbiological Specifications for Foods (ICMSF) standard for both fresh and frozen finfish is maximum (M) of 10 7 CFU/g [10].…”

Ankara yöresindeki alabalık çifliklerinde Salmoneıla varlığı

“…Güney Hindistan'da balıkların avlandığı sulara kanalizasyon suları ve kuş dışkılarının karışması, balıkların taşınması sırasında kullanılan buzun ucuz ve düşük kalitede olması, hijyenik olmayan ellerle balıkların kasalara yerleştirilmesi, kontamine su ile balıkların ıslatılması ve sineklerin yoğun olması nedeniyle Salmonella'nın prevalansının oldukça yüksek olduğu görülmüştür (16).…”