By Ibrahim Magawata (PhD)

FISH QUALITY AND HEALTH

• Introduction• Why Fish quality?• Reason for spoilage of fish • Methods of quality evaluation • Handling and preservation practices • Health importance of fish • Conclusion

INTRODUCTION

INTRODUCTION The world is blessed with abundant water bodies.These water bodies (marine & freshwater)contained over 32,000 species of fish. Nigeria’sInland Fisheries include Lake Chad, River Niger,River Benue, lake Kainji, River Rima. Etc.

Fish demand in Nigeria is over 2.5 million metric tons annually but production is about 600,000 tons (FAO,2013). Some fresh water fish species are as follows:

FAMILY NAME SCIENTIFIC NAME COMMON NAME

Centropomidae Lates niloticus Giwan RuwaClariidae Clarias gariepinus Tarwada

Heterobranchus Longifilis RamboshiHeterobranchus bidarsalis Ramboshi

Protopteridae Protopterus annectens Gawo/BodamiGymmarchidae Gymnarchus niloticus Yauni/Dan sarkiOsteoglossidae Heterotis niloticus BalliMormyridae Hyperopisus bebe occidentalis KumaMormyridae Mormyrus rume Kuma

Baqaridae Chrysichthys nigrodigitatus LaliBagrus bayad macropterus Ragon Ruwa

Mochokidae synodontis eupterus KurunguChichlidae Oreochromis niloticus Gargaza

Sarotherodon galielius GargazaCitharidae Citharinus citharus FaliyaPolypteridae Polypterus senegalsus Gwando

Calamichthys calabaricus Gwando

TABLE 1: CAPTURE FISHERIS PRODUCTION BY WEST AFRICAN COUNTRIES, 2005 – 2011 (TONS)

Country Population‘000

2005 2006 2007 2008 2009 2010 2011

Benin 9100 31497 41507 36386 37495 38928 39791 38848BurkinaFaso

16968 9000 9500 10200 11093 11800 14520 15000

CoteDivoire

20153 42655 54830 47289 50000 44198 69517 71719

Chad 11512 55000 50000 45000 40000 40000 50000 60000Gambia 1776 34586 36912 43574 42645 45881 46424 45000Ghana 24966 391866 375067 330486 359831 321815 351205 333542

Guinea 10222 109138 104718 82073 94513 127746 113504 115000

GuineaBisssau

1547 6983 7067 6500 6804 672 6750 6750

Liberia 4129 12147 8894 14488 7890 8000 8000 8000Mali 15840 100000 100000 100000 100000 100000 100000 108134

Mauritania 3642 304877 165312 223207 195328 21690 276236 372011

Niger 16069 50018 29835 29728 29960 29884 40000 53173Nigeria 162471 523182 552323 530420 601368 598210 616981 635486

Senagal 12768 400118 366989 412835 425729 442233 409485 427133

Sierra Leone 5997 145993 148146 144535 203582 200000 200000 199000

Togo 6155 27732 24879 19905 22765 27025 27535 24122

SOURCE: FAO(2013)

PICTURES OF SOME FISH SPECIES

Lates niloticus

FISH

Bagrus bayad macropterus

FISH

Heterobranchus bidorsalis

Clarias gariepinus Burchell

Citharinus citharus

Bagrus docmac/bayad macropterus

GYMNARCHUS NILOTICUS

Gymnarchus niloticus

WHY FISH QUALITY ?

EYO, (fish, 2001) defined quality as the characteristics or attributes which make fish acceptable to the consumer.

In assessing quality of fish, the consumer may consider

a. Its freshness b. Safety of fish in terms of

i. Microbial load ii. Presence or absence of pathogenic organisms ‘iii. Palatabilty

Quality of fish raw materials plays an important role for the quality of the end product

Its deterioration can start right away during fishing and it continues all the way to the final consumer

Irreversible damage

REASON FOR THE SPOILAGE OF FISH

Rigor mortis phenomenon Autolysis BacteriaRancidity

Bacteria 0 day (%) 5 days (%) 10 days (%) 15 days (%)

Pseudomonas 14 17 50 82

Achromobacter 33 49 38 14

Flavobacterium 4 0 0 2

Coryneform 41 33 12 2

Micrococcus 8 1 0 0

Total 100% 100%

100% 100%

Table 2: The relative change in abundance of different groups of bacteria in cod stored in ice (Hobbs 1982).

HANDLING AND PRESERVATION

- Fish start to spoil immediately it is caught - However, the rate of spoilage is different

depending on ambient conditions, fishing technology, equipment, species of fish and handling and preservation activities

- Control of temperature - Fish chilling should be carried out immediately

after gutting - It should not be exposed to sunshine and wind to

avoid autolytic oxidation and bacterial spoilage.

Gutting to remove visceral parts/organs before chilling Fish should be stored in insulated plastic cold boxes The premises of middlemen/fish mongers must be of

good hygienic conditions Use good quality ice and water Better sanitary facilities Strict adherence to cleaning schedule of utensils,

tables, equipment, floor etc. Prevention of entry of insects, rodents and birds into

handling and processing areas. Fish soaking is an economic fraud

METHODS FOR QUALITY EVALUATION

A. Objective i. Chemical (TVB-N, TMA, PH etc)ii. Microbiological iii. Physical

B. Subjective i. Sensory evaluationCHARACTERISTIC OF FISH - The flesh is firm and when it is pressed, it leaves no permanent

indentation - The skin looks shiny - The eyes are clear and well rounded in shape - The gills are bright red or pink in color - The fish has a fresh smell like that of seaweeds

CHARACTERISTIC OF SPOILT FISH

- The flesh is soft to touch. When the flesh is pressed itleaves permanent indentation

- The skin looks dull and has slime on the surface- Scales are removed when rubbed- The gills look brownish in color- The eyes are cloudy and sunken not bulging- It gives a bad smell like ammonia

HEALTH IMPORTANT OF FISH

Fish has a reputation for being low calories, high protein“brain food” because of the long stands of polyunsaturatedessential omega-3 fatty acids.

Human body cannot naturally produce omega-3 but yet they are needed for healthy body.

Fish is also known to contain vitamins such as D and B2 . It isrich in calcium, phosphorous and great source of mineralssuch as iron, zinc, iodine, magnesium and potassium.

Hibben et al, (2007) reported that eating fish once or twice aweek is enough to allow one to reap the above benefits.

Here are some reason why you should add a dose of fish into your diet to improve your health.

PREVENT HEART DISEASE:A Danish study of 49,000 women that was published in Hypertension:

Journal of the American Heart Association found that women who atelittle to no fish had 50 percent more heart problems than those whoate fish at least once per week. Additionally, researchers found thatwomen who rarely ate fish had a three-fold higher disease risk thanthose who ate it often. Other research has found that eating fish high inomega-3s can slash blood fat levels, which can contribute to a lowerheart-disease risk (Albert et. al., 2005 and Raji et. al., 2014)

Reduce Alzheimers risk Improve skin and hair Ease depression Boost brain development Asthma in children Eye sight Inflammatory conditions (rhematoid arthritis,

Psoriasis and autoimmune disease) Prematurity Protect lungs

STRONGER SPERM:

A recent study of 188 men found that those who atemore fresh fish — along with other healthy foods such asfruits, vegetables, and whole grains — had strongerswimmers than those who ate unhealthy diets.Researchers say that more study needs to be done, butpreliminary data shows that the better the participant’sdiet, the stronger the shape and mobility of the spermhe produced.

CONCLUSION

In conclusion, I would want to emphasize the need forconsumers to be keen and vigilant on the quality of fishthey buy in order to benefit from its nutritional andhealth importance. There is no one single food thatprovides health benefits as fish does in this world.

ACKNOWLEDGEMENT

I would like to appreciate and acknowledge the valuable assistance of the following

The vice chancellor for his motivation Chairman and members of the university seminar

committee for their persuasion in actualizing this presentation .

Mal. Muh’d Yahaya Abubakar for sending some pictures of fish and many staff of FUBK and UDUS that assisted directly or indirectly in making this presentation a success.

Thank you all

ALWAYS EAT FISH