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Abstract
A total of 250 fish samples comprised three fish species, 50 of each fresh water fish (Tilapia nilotica) either marketed and cultured, frozen mackerel, smoked fish (packed and unpacked) were randomly collected from different shops and retail markets of different sanitation levels at Giza Governorate.
The samples were examined for their organoleptic and mycological quality.
1. Sensory assessment (evaluation):
The organoleptic examination revealed that all of the examined cultured Tilapia nilotica were showed grade 3 fishes (very fresh) while 52% of the examined marketed Tilapia nilotica showed skin conditions.
Twenty percent of the inspected parts of 50 frozen mackerel fish samples were judged as grade E (highest quality). The skin, texture of the body and eyes were found to be as grade A quality and represented by 60% of the examined samples.
Seventy sex percent of the unpacked smoked fish samples has intact skin while all of the packed smoked fish samples had the same criteria. Hundred percent of the packed smoked fish had salty taste and smoked fishy flesh odour while the bitter taste were recorded in 12% only of the unpacked smoked fish and 4% of the same samples had musty odour.
Regarding to the acceptability of examined fishes, 92% of Tilapia nilotica were accepted while cultured Tilapia nilotica 100% were accepted. The frozen mackerel fish samples did not rejected organoleptically. The highest percentage (12%) of rejection was recorded in unpacked smoked fish. The packed smoked fish were 100% accepted organoleptically.
2. pH evaluation:
pH values of marketed Tilapia nilotica, cultured Tilapia nilotica, frozen mackerel fish, unpacked and packed smoked fish were 6.46 ± 0.001, 5.57 ± 0.01, 6.09 ± 0.01, 5.52 ± 0.01 and 5.69 ± 0.01, respectively.
3. Mycological criteria of examined fish:
3.1. Mould counts of fish samples:
The mean mould count/cm2 of examined fish samples were 2 X 103 ± 8 X 10 for marketed Tilapia nilotica, 3 X 102 ± 0.4 X 10 for cultured Tilapia nilotica, 1 X 102 ± 0.3 X 10 for frozen mackerel fish, 8 X 103 ± 3 X 10 for unpacked smoked fish and 1 X 103 ± 5 X 10 spores/cm2 for packed smoked fish. The highest mould count was recorded in unpacked smoked fish while the lowest value was obtained from frozen mackerel fish. 82% of marketed Tilapia nilotica were in the range of > 102, while 78% only of cultured Tilapia nilotica in this range. Frozen mackerel fish, the percentage was only 50%. In either smoked unpacked and packed smoked fish each constituting 92% and 78%, respectively.