Untitled - Stiftung Tierärztliche Hochschule Hannover

7 Summary
In comparison of the tested fish species (eel, rainbow trout, catfish) and their
products the fish species catfish and its products showed the highest bacterial
contamination of muscle tissue with respect to the parameters total aerobic plate
count at 25°C and at 30°C and Pseudomonas. Freshly slaughtered rainbow trouts
presented with a total aerobic plate count of 3.57 ± 2.08 CfU/g at 30°C and
3.47 ± 1.96 CfU/g at 25°C and with 1.73 ± 1.2 CfU/g for Pseudomonas spp. the
lowest bacterial contamination of muscle tissue compared to other fish products.
The highest bacterial counts for the total aerobic bacterial count 30°C
(5.07 ± 0.55 CfU/g) at the beginning of the given shelf live were found in smoked
catfish products.
Enterobacteriaceae were rarely found both in the environment of process lines as
well as in fishery products.
The evaluation of the hygienic conditions at companies revealed a significant relation
between slaughter tools and fresh slaughtered fishes at the slaughtering process.
Though Pseudomonas was the dominating bacterial flora it has been detected up to
1.9x10 5 CfU/cm²on the surfaces of slaughtering dish, up to 1.3x10 7 CfU/sampling
points on slaughter-brushes, with 1.7x10 6 CfU/cm² on butcher´s knives and up to
4.0x10 4 CfU/g on fresh slaughtered fishes.
The evaluation of cross-contaminations between sluices and the sample places right
next to them as well as pre-, intermediate- and endproducts yielded an correlation
between the sampling groups slaughter - room sluice and slaughtering dish for the
microbiological parameters total aerobic bacterial count 25°C and 30°C. There also
consisted a correlation between the sample groups slaughtering dish, brush,
slaughter - knife and the slaughter room – sluice in view of the microbiological
parameter Pseudomonas (p