<p>The microbial contamination during production, transport, processing and distribution of fishes possesses problems of infection and spoilage which manifests itself as changes in the sensory characteristics. High ambient temperature and humidity favour the microbial growth and in turn spoilage of fish. It may develop differently depending on geographical origin and other unknown factors interacting with the microbial development. The high post mortem pH in the flesh of fish, the presence of large amounts of non-protein-nitrogen, besides its poikilotherm nature and aquatic environment influence the microbial spoilage of flesh (<xref ref-type="bibr" rid="bib003">Gram and Huss, 1996</xref>). In India, studies have been carried for enterobacteria in prawns (<xref ref-type="bibr" rid="bib007">Sahoo and Bachhil, 1994</xref>) and microbial quality of marine fishes (<xref ref-type="bibr" rid="bib008">Singh, 1997</xref>). There are no studies available on microbial quality of fishes in Goa region. Therefore, a study has been carried out to assess the microbial load of fishes sold in Goa region.</p><p>A total of 76 (38 each from rural and urban areas) fresh samples of marine fishes were collected randomly from fish markets of Goa in U.V. sterilized polyethylene sachets, transported on ice, stored at 4°C and processed for microbiological analysis within 24 hrs of collection.</p><p>The fish samples were analyzed for pH (<xref ref-type="bibr" rid="bib001">AOAC, 1975</xref>) and total plate count for mesophiles, psychrophiles, and yeast and mould counts (<xref ref-type="bibr" rid="bib005">ICMSF, 1978</xref>).</p><p>Bacterial colonies obtained from the samples were selected randomly for confirmation. The isolates were subjected to morphological and biochemical identification (Carter, 1995). Selected isolates were subjected to drug sensitivity by disc diffusion method.</p><p>The pH of the fish samples varied from 5.82 to 7.31. In the samples colleted from urban markets the pH range was 5.84 to 7.31 whereas, in the samples from rural markets it was 5.82 to 7.21. Fish flesh has been reported to have high (>6.0) postmortem pH (<xref ref-type="bibr" rid="bib003">Gram and Huss, 1996</xref>) which has important consequences for the microbiology of fishes. The average mesophilic and psychrophilic counts of the fishes varied from 2.24 to 8.05 log<sub>10</sub> cfu/g and 4.94 to 8.05 log<sub>10</sub> cfu/g, and 3.00 to 7.11 and 3.00 to 7.47 log<sub>10</sub> cfu/g in urban and rural markets, respectively (<xref ref-type="table" rid="tab001">Table 1</xref>). The yeast and mould counts were 3.00 to 8.05 and 3.00 to 8.00 log<sub>10</sub> cfu/g in fishes from urban and rural markets, respectively. The mesophilic counts are comparable to those reported by Singh (<xref ref-type="bibr" rid="bib008">1997</xref>) as 8 x 10<sup>6</sup> to 70 x 10<sup>6</sup>/g. The counts of mesophiles, psychrophiles, and yeast and moulds reported were higher, which could be due to the tropical climatic conditions of Goa like temperature and humidity which enhanced the activity microbes. Foster <italic>et al.</italic> (<xref ref-type="bibr" rid="bib002">1977</xref>) and Himmebloom and Crapo (<xref ref-type="bibr" rid="bib004">1998</xref>) have also reported higher microbial counts in marine fishes. <table-wrap id="tab001"><label>Table 1</label><caption><p>Microbial counts (log<sub>10</sub> cfu/g) of marine fishes from retail outlets.</p></caption><table><thead><tr><th rowspan="3">Source</th><th rowspan="3" align="center">No. of Samples</th><th colspan="2" align="center">pH</th><th colspan="2" align="center">Mesophiles</th><th colspan="2" align="center">Psychrophiles</th><th colspan="2" align="center">Yeast and moulds</th></tr><tr><th colspan="2"><hr /></th><th colspan="2"><hr /></th><th colspan="2"><hr /></th><th colspan="2"><hr /></th></tr><tr><th align="center">Range</th><th align="center">Mean</th><th align="center">Range</th><th align="center">Mean</th><th align="center">Range</th><th align="center">Mean</th><th align="center">Range</th><th align="center">Mean</th></tr></thead><tbody><tr><td colspan="10"><hr /></td></tr><tr><td>Urban markets</td><td align="center" valign="top">38</td><td align="center" valign="top">5.84 −7.31</td><td align="center" valign="top">6.68</td><td align="center" valign="top">2.24−8.05</td><td align="center" valign="top">6.51</td><td align="center" valign="top">3.0−7.11</td><td align="center" valign="top">5.23</td><td align="center" valign="top">3.0−8.05</td><td align="center" valign="top">5.83</td></tr><tr><td>Rural markets</td><td align="center" valign="top">38</td><td align="center" valign="top">5.82−7.21</td><td align="center" valign="top">6.64</td><td align="center" valign="top">4.94−8.05</td><td align="center" valign="top">6.90</td><td align="center" valign="top">3.0−7.47</td><td align="center" valign="top">4.93</td><td align="center" valign="top">3.0−8.00</td><td align="center" valign="top">5.95</td></tr><tr><td>Total</td><td align="center" valign="top">76</td><td align="center" valign="top">5.82−7.31</td><td align="center" valign="top">6.66</td><td align="center" valign="top">2.24−8.05</td><td align="center" valign="top">6.70</td><td align="center" valign="top">3.0−7.47</td><td align="center" valign="top">5.08</td><td align="center" valign="top">3.0−8.05</td><td align="center" valign="top">5.89</td></tr></tbody></table></table-wrap></p><p>The high microbial load might also be due to the over crowding and dusty environment of the markets, unhygienic handling of fishes by vendors and not maintaining the optimum preservative temperatures.</p><p>The genera of bacteria confirmed were <italic>Alcaligenes, Enterobacter, Shigella, Escherichia coli, Klebsiella, Proteus, Pseudomonas, Salmonella, Serratia, Citrobacter, Bacillus, Staphylococcus, Micrococcus</italic> and <italic>Chromobacterium.</italic> The flora of tropical fish often carries a slightly higher load of Gram positive and enteric bacteria (<xref ref-type="bibr" rid="bib006">Liston, 1980</xref>). The incidence of microorganisms in seafoods greatly depends upon the quality of waters from which they are harvested.</p><p><italic>In vitro</italic> antibiotics sensitivity test revealed that the bacterial genera were highly sensitive to ciprofloxacin (100%), norfloxacin (100%), chloramphenicol (91.66%) and, oxytetracycline and gentamicin (83.33%) (<xref ref-type="table" rid="tab002">Table 2</xref>). <table-wrap id="tab002"><label>Table 2</label><caption><p><italic>In-vitro</italic> antibiotic sensitivity testing of the isolates.</p></caption><table><thead><tr><th>Antibiotics used</th><th align="center">% sensitive</th></tr></thead><tbody><tr><td colspan="2"><hr /></td></tr><tr><td>Gentamicin</td><td align="center">83.33</td></tr><tr><td>Ampicillin</td><td align="center">58.33</td></tr><tr><td>Ciprofloxacin</td><td align="center">100</td></tr><tr><td>Oxytetracycline</td><td align="center">83.33</td></tr><tr><td>Penicillin-G</td><td align="center">58.33</td></tr><tr><td>Norfloxacin</td><td align="center">100</td></tr><tr><td>Chloramphenicol</td><td align="center">91.66</td></tr></tbody></table></table-wrap></p><p>A thorough understanding of the spoilage process and knowledge of the specific spoilage organisms are necessary for the design of an optimal, product specific quality assurance programmes. Further studies on isolation of specific pathogens from seafood are underway.</p></sec></body><back><ack id="ack001"><title>Acknowledgements

IJCMIID

Indian Journal of Comparative Microbiology, Immunology and Infectious Diseases

0790-9320

Indian Association of Veterinary Microbiologists, Immunologists and Specialists in Infectious Diseases

ijcmiid-25-1-022

SHORT COMMUNICATION

Microbiological quality of marine fishes of Goa region

Gadi

Subhadra Devi

Nair

Viegas

Vaz

B. Barbuddhe

Department of Zoology, Carmel College for Women, Nuvem, Goa - 403 604

*Correspondong author

1–62004

2517374

<p>The microbial contamination during production, transport, processing and distribution of fishes possesses problems of infection and spoilage which manifests itself as changes in the sensory characteristics. High ambient temperature and humidity favour the microbial growth and in turn spoilage of fish. It may develop differently depending on geographical origin and other unknown factors interacting with the microbial development. The high post mortem pH in the flesh of fish, the presence of large amounts of non-protein-nitrogen, besides its poikilotherm nature and aquatic environment influence the microbial spoilage of flesh (<xref ref-type="bibr" rid="bib003">Gram and Huss, 1996</xref>). In India, studies have been carried for enterobacteria in prawns (<xref ref-type="bibr" rid="bib007">Sahoo and Bachhil, 1994</xref>) and microbial quality of marine fishes (<xref ref-type="bibr" rid="bib008">Singh, 1997</xref>). There are no studies available on microbial quality of fishes in Goa region. Therefore, a study has been carried out to assess the microbial load of fishes sold in Goa region.</p><p>A total of 76 (38 each from rural and urban areas) fresh samples of marine fishes were collected randomly from fish markets of Goa in U.V. sterilized polyethylene sachets, transported on ice, stored at 4°C and processed for microbiological analysis within 24 hrs of collection.</p><p>The fish samples were analyzed for pH (<xref ref-type="bibr" rid="bib001">AOAC, 1975</xref>) and total plate count for mesophiles, psychrophiles, and yeast and mould counts (<xref ref-type="bibr" rid="bib005">ICMSF, 1978</xref>).</p><p>Bacterial colonies obtained from the samples were selected randomly for confirmation. The isolates were subjected to morphological and biochemical identification (Carter, 1995). Selected isolates were subjected to drug sensitivity by disc diffusion method.</p><p>The pH of the fish samples varied from 5.82 to 7.31. In the samples colleted from urban markets the pH range was 5.84 to 7.31 whereas, in the samples from rural markets it was 5.82 to 7.21. Fish flesh has been reported to have high (>6.0) postmortem pH (<xref ref-type="bibr" rid="bib003">Gram and Huss, 1996</xref>) which has important consequences for the microbiology of fishes. The average mesophilic and psychrophilic counts of the fishes varied from 2.24 to 8.05 log<sub>10</sub> cfu/g and 4.94 to 8.05 log<sub>10</sub> cfu/g, and 3.00 to 7.11 and 3.00 to 7.47 log<sub>10</sub> cfu/g in urban and rural markets, respectively (<xref ref-type="table" rid="tab001">Table 1</xref>). The yeast and mould counts were 3.00 to 8.05 and 3.00 to 8.00 log<sub>10</sub> cfu/g in fishes from urban and rural markets, respectively. The mesophilic counts are comparable to those reported by Singh (<xref ref-type="bibr" rid="bib008">1997</xref>) as 8 x 10<sup>6</sup> to 70 x 10<sup>6</sup>/g. The counts of mesophiles, psychrophiles, and yeast and moulds reported were higher, which could be due to the tropical climatic conditions of Goa like temperature and humidity which enhanced the activity microbes. Foster <italic>et al.</italic> (<xref ref-type="bibr" rid="bib002">1977</xref>) and Himmebloom and Crapo (<xref ref-type="bibr" rid="bib004">1998</xref>) have also reported higher microbial counts in marine fishes. <table-wrap id="tab001"><label>Table 1</label><caption><p>Microbial counts (log<sub>10</sub> cfu/g) of marine fishes from retail outlets.</p></caption><table><thead><tr><th rowspan="3">Source</th><th rowspan="3" align="center">No. of Samples</th><th colspan="2" align="center">pH</th><th colspan="2" align="center">Mesophiles</th><th colspan="2" align="center">Psychrophiles</th><th colspan="2" align="center">Yeast and moulds</th></tr><tr><th colspan="2"><hr /></th><th colspan="2"><hr /></th><th colspan="2"><hr /></th><th colspan="2"><hr /></th></tr><tr><th align="center">Range</th><th align="center">Mean</th><th align="center">Range</th><th align="center">Mean</th><th align="center">Range</th><th align="center">Mean</th><th align="center">Range</th><th align="center">Mean</th></tr></thead><tbody><tr><td colspan="10"><hr /></td></tr><tr><td>Urban markets</td><td align="center" valign="top">38</td><td align="center" valign="top">5.84 −7.31</td><td align="center" valign="top">6.68</td><td align="center" valign="top">2.24−8.05</td><td align="center" valign="top">6.51</td><td align="center" valign="top">3.0−7.11</td><td align="center" valign="top">5.23</td><td align="center" valign="top">3.0−8.05</td><td align="center" valign="top">5.83</td></tr><tr><td>Rural markets</td><td align="center" valign="top">38</td><td align="center" valign="top">5.82−7.21</td><td align="center" valign="top">6.64</td><td align="center" valign="top">4.94−8.05</td><td align="center" valign="top">6.90</td><td align="center" valign="top">3.0−7.47</td><td align="center" valign="top">4.93</td><td align="center" valign="top">3.0−8.00</td><td align="center" valign="top">5.95</td></tr><tr><td>Total</td><td align="center" valign="top">76</td><td align="center" valign="top">5.82−7.31</td><td align="center" valign="top">6.66</td><td align="center" valign="top">2.24−8.05</td><td align="center" valign="top">6.70</td><td align="center" valign="top">3.0−7.47</td><td align="center" valign="top">5.08</td><td align="center" valign="top">3.0−8.05</td><td align="center" valign="top">5.89</td></tr></tbody></table></table-wrap></p><p>The high microbial load might also be due to the over crowding and dusty environment of the markets, unhygienic handling of fishes by vendors and not maintaining the optimum preservative temperatures.</p><p>The genera of bacteria confirmed were <italic>Alcaligenes, Enterobacter, Shigella, Escherichia coli, Klebsiella, Proteus, Pseudomonas, Salmonella, Serratia, Citrobacter, Bacillus, Staphylococcus, Micrococcus</italic> and <italic>Chromobacterium.</italic> The flora of tropical fish often carries a slightly higher load of Gram positive and enteric bacteria (<xref ref-type="bibr" rid="bib006">Liston, 1980</xref>). The incidence of microorganisms in seafoods greatly depends upon the quality of waters from which they are harvested.</p><p><italic>In vitro</italic> antibiotics sensitivity test revealed that the bacterial genera were highly sensitive to ciprofloxacin (100%), norfloxacin (100%), chloramphenicol (91.66%) and, oxytetracycline and gentamicin (83.33%) (<xref ref-type="table" rid="tab002">Table 2</xref>). <table-wrap id="tab002"><label>Table 2</label><caption><p><italic>In-vitro</italic> antibiotic sensitivity testing of the isolates.</p></caption><table><thead><tr><th>Antibiotics used</th><th align="center">% sensitive</th></tr></thead><tbody><tr><td colspan="2"><hr /></td></tr><tr><td>Gentamicin</td><td align="center">83.33</td></tr><tr><td>Ampicillin</td><td align="center">58.33</td></tr><tr><td>Ciprofloxacin</td><td align="center">100</td></tr><tr><td>Oxytetracycline</td><td align="center">83.33</td></tr><tr><td>Penicillin-G</td><td align="center">58.33</td></tr><tr><td>Norfloxacin</td><td align="center">100</td></tr><tr><td>Chloramphenicol</td><td align="center">91.66</td></tr></tbody></table></table-wrap></p><p>A thorough understanding of the spoilage process and knowledge of the specific spoilage organisms are necessary for the design of an optimal, product specific quality assurance programmes. Further studies on isolation of specific pathogens from seafood are underway.</p></sec></body><back><ack id="ack001"><title>Acknowledgements

The authors are thankful to the Director, ICAR Research Complex for Goa, Ela, Old Goa for providing necessary facilities.

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