Natural origins of off-flavours in fish related to feeding habits.

The objective of our study was to survey the accumulated 2-methylisoborneol (MIB) and geosmin (GSM) in fillets of five important farmed fish species in Hungarian aquaculture in relation to MIB and GSM concentrations in water and sediment in the aquatic systems where they were raised: (the planktivorous silver carp (Hypophthalmichthys molitrix), the herbivorous grass carp (Ctenopharyngodon idella), the bottom-feeding omnivorous common carp (Cyprinus carpio), the omnivorous tilapia (Oreochromis niloticus) and the carnivorous African catfish (Clarias gariepinus)). Water, sediment and fish samples were collected from different experimental aquatic systems which included a combined aquaculture-algae (CAA) system, effluent-fed fishponds, a pond recycling system and a traditional fishpond. MIB and GSM contents were extracted with distillation-headspace solid-phase-microextraction (SPME) and extracts analysed by GC-MS. Results showed that off-flavour contents in fish fillets were related to the feeding habits of the studied fish species. Higher GSM concentrations were found in the fillet of bottom-feeding common carp than in the silver carp or African catfish in all studied aquatic systems. Usually, low GSM concentrations were detected in the water of fishponds but sometimes the levels of this odour compound in carp fillet were well above the limits of human detection. This suggests that the off-flavour tainting of common carp may originate from the sediment or benthic algallactinomycete sources. Negligible MIB levels were found in all samples in all of the studied aquatic systems.

[Should fiber gastroscopy be standard in preoperative examinations for cardiac surgery?]. / Má byt' gastrofibroskopické vysetrenie pred operáciou srdca standardným vysetrením?

UNLABELLED: We introduced a gastrofibroscopy into a standard preoperative protocol for all patients indicated to the cardiac surgery. AIM OF THE STUDY: Validation of our protocol. MATERIAL AND METHODS: 957 consecutive patients operated on from May 1995 to January 2002 were divided to group A--gastrofibroscopy only for patients with positive history or clinical signs of peptic ulcer (151 pts.) and group B--patients with gastrofibroscopy as a standard procedure (806 pts). RESULTS: Significant difference in incidence of peptic ulcer complications between groups (A--5.9% versus B--1.1%, p < 0.05). Related mortality was 1.3% in-group A versus 0% in-group B. Positive history of peptic ulcer had only two patients (11% of 18) with postoperative complication. In-group B we found high incidence of peptic defects (B--35% versus A--9%, p < 0.01) requiring treatment by gastroenterologist. Majority (230 of 281-82%) of pts. with preoperative positive defect had negative history of a peptic ulcer. CONCLUSIONS: Current tendency to perform gastrofibroscopic examination only in patients with positive history of peptic ulcer is not able to detect "silent" lesions. Perioperative treatment with H2 blockers fails to prevent the manifestation of peptic ulcer complication. Gastrofibroscopy should be a routine part of the preoperative protocol in cardiac surgery.