Fish Microbiology

This study was conducted to confirm the bacterial conditions of fish products with E.O.S, and its hazards on public health. A total
of 60 samples of fish products (smoked fish: herring and smoked salmon–semi cooked fish: fish finger and breaded shrimp) (15 of
each) were collected from different retail markets for bacteriological examination. The average of APC, Coliform, Escherichia coli,
Mould and yeast and Staphylococcal aureus counts (log10 cfu/g) were 4.17 ± 0.12, 2.92 ± 0.16, 2.19 ± 0.23, 3.96 ± 0.14 and 1.72 ± 0.21
for herring, respectively, 3.16 ± 0.19, 2.69 ± 0.13, 1.22 ± 0.16, 2.22 ± 0.18 and 1.06 ± 0.06 in smoked salmon, respectively, 2.78 ± 0.12,
2.02 ± 0.22, 1.59 ± 0.22, 2.14 ± 0.15 and 1.24 ± 0.24 in fish finger, respectively, and 2.60 ± 0.13, 2.33 ± 0.14, 1.46 ± 0.23, 1.96 ± 0.20,
0 ± 0 in breaded shrimp, respectively. The incidence of food poisoning organisms (Salmonella and Listeria monocytogenes and Vibrio
parahaemolyticus also investigated and no one of them was isolated in the examined samples.

A B S T R A C T A total of 90 random samples of Saurus, Mackerel and Horse Mackerel (30 of each) were collected from different fish markets in El-Kalubia governorate to be examined bacteriologically for determination of psychrotrophic and Pseudomonas count in such examined samples. The bacteriological examination revealed the mean values of total psychrotrophic count and pseudomonas count in the examined samples of Saurus were 4.08 x 10 5 ± 0.71 x 10ْ ْ ْ ْ ْ ْ 5and 1.26 x 10 4 ± 0.32 x 10 4 cfu/g respectively. 9.95 x 10 4 ± 2.13 x 10 4 , and 5.13 x 10 3 ± 0.91 x 10 3 x 10 3 / gm respectively. in Mackerel ,3,66 x 10 4 ± 0.49 x 10 4 , and 2,47 x 10 3 ± 0.55 x 10 3 /g, in Horse Mackerel.. The incidence of Pseudomonas species were 76.67% 66.67% and 63.33% of the examined samples of Saurus, Mackerel and Horse Mackerel, respectively. The differences between the examined samples of different frozen fish as result of total psychrotrophic count, and total pseudomonas count were highly significant (P< 0.01). Public Health significant of isolated psychrotrophic bacteria and possible sources of fish contamination with such organisms as well as some recommendations to improve the quality of fish were discussed.

One hundred random samples of local and imported canned Tuna and Mackerel fish (25 of each) were
analyzed for detection and determination of biogenic amines residues (histamine, tyramine and
putrescine) by High Performance Liquid Chromatography (HPLC). The obtained results revealed that
the average concentration levels of histamine, tyramine, and putrescine (mg/kg) were 22.86±0.72,
0.274±0.035 & 1.884±0.181, 19.48±0.64, 0.184±0.177& 1.72±0.076, 36.72±1.807, 0.393±0.048 &
2.1±0.104, 29.04±1.46, 0.368±0.047 and 1.894±0.115 for local and imported tuna and mackerel
samples, respectively. All Samples of both canned tuna and mackerel were acceptable for histamine,
tyramine and putrescine Except 8% of local canned mackerel A exceeded permissible limits for
histamine according to Egyptian Organization of Standardization (EOS, 2005).

A B S T R A C T A total of 90 random samples of Saurus, Mackerel and Horse Mackerel (30 of each) were collected from different fish markets in El-Kalubia governorate to be examined bacteriologically for determination of psychrotrophic and Pseudomonas count in such examined samples. The bacteriological examination revealed the mean values of total psychrotrophic count and pseudomonas count in the examined samples of Saurus were 4.08 x 10 5 ± 0.71 x 10ْ ْ ْ ْ ْ ْ 5and 1.26 x 10 4 ± 0.32 x 10 4 cfu/g respectively. 9.95 x 10 4 ± 2.13 x 10 4 , and 5.13 x 10 3 ± 0.91 x 10 3 x 10 3 / gm respectively. in Mackerel ,3,66 x 10 4 ± 0.49 x 10 4 , and 2,47 x 10 3 ± 0.55 x 10 3 /g, in Horse Mackerel.. The incidence of Pseudomonas species were 76.67% 66.67% and 63.33% of the examined samples of Saurus, Mackerel and Horse Mackerel, respectively. The differences between the examined samples of different frozen fish as result of total psychrotrophic count, and total pseudomonas count were highly significant (P< 0.01). Public Health significant of isolated psychrotrophic bacteria and possible sources of fish contamination with such organisms as well as some recommendations to improve the quality of fish were discussed.

A 13.4 L biofilter was used to treat a polluted air stream using methanol as a model pollutant. This unit was operated under two situations: i) with pine bark chips randomly packed with no pH control of the aqueous phase (P1) and; ii) with a structured packing formed by PVC rings and with a pH control system of the aqueous phase (P2). During P1 a continuous drop in pH was observed, from neutral values down to pH 2 after 60 days of operation. Biofilm developed in a homogeneous manner over all available areas of the support. Heterotrophic activity achieved 0.40.5 kg COD/kg VSS·d at the end of operation. The application of the FISH technique indicated that eukaryotic microorganisms were predominant over bacteria. Besides, the application of the PCR technique, by means of cloning and sequencing, allowed the identification of the main eukaryotes present: the fungi Candida boidinii, Nectria Mariannaeae, Scytalidium lignicola and Hydrocina chaetocladia. During the second period (P2), methanol removal observed was higher, close to 99.9%, after the first month of operation. In this case, biofilm was developed in a homogeneous manner over all rings, with much higher heterotrophic activity. The application of the FISH technique indicated in this case a clear predominance of eubacteria, although archaea and a minor presence of eukaryotic microorganisms were also present.

To date, it has been increasingly clear, that microbiota plays essential role in the host microorganism. Due to high phylogenetic diversity and wide distribution understanding of gut microbiota of fish is ambiguous. We elucidate previously undescribed diversity of bacteria in the White Sea fish posterior intestine based on 16S rRNA metabarcoding: shorthorn sculpin (Myoxocephalus scorpius), lumpfish (Cyclopterus lumpus) arctic flounder (Liopsetta glacialis), cod (Gadus morhua), and herring (Clupea pallasii). Proteobacteria were most abundant in all the samples. All datasets contained high number of reads corresponded to Psychrobacter, Halomonas, Pseudoalteromonas and Vibrio abundant in the White Sea water.Vast majority of bacterial reads corresponded to the Vibrionaceae (Aliivibrio, Vibrio, and Photobacterium). It is in accordance with our previous study focused on bioluminescent bacteria, where we isolated strains of these genera from the same fish intestine samples. The datasets of G. morhua and Cl. pallasii were enriched by reads of Shewanella (also isolated previously microbiologically due to luminescence of some its strains); the datasets of G. morhua and M. scorpius contained high number of Mycoplasma, which is in line with previous reports on the microbiome of marine fish gut from other geographical regions. Collectively, on the one hand, the study is a confirmation of known data on marine fish gut microbiome, on the other hand, it reveals some specific patterns of White Sea fish gut microbiota, e.g. presence of bacteria common for water from this region.