Nutritional and microbial evaluation of some frozen marine fish species sold in selected local government areas of Kano State, Nigeria

Lawal, Kasim Ibrahim; Bichi, Armaya'u Hamisu; Moruf, Rasheed Olatunji; Maradun, Hassan Faruk; Dauda, Akeem Babatunde

doi:10.4025/actascianimsci.v48i1.74710

Abstract

ABSTRACT. This study was carried out to evaluate the nutritional compositions and microbial load of some frozen marine fish species sold in Kano State, Nigeria. A total of 81 samples comprising 27 each of Atlantic herring (Clupea harengus), Atlantic mackerel (Scomber scombrus) and Atlantic horse mackerel (Trachurus trachurus) were purchased from three sampling areas: Bichi, Dambatta and Gwarzo. They were analysed for proximate, mineral compositions, and microbial load using standard procedures. Results indicated that the highest crude protein content, 21.51% was recorded in T. trachurus from Dambatta, while the mineral composition revealed that C. harengus recorded the highest sodium content, 1.69 mg Kg^-1, from Bichi. The highest free fatty acids 2.07 ± 0.18% was observed in T. trachurus from Gwarzo. The results of the microbial population elucidated that T. trachurus had the highest Salmonella spp. count of 4.22 x 10⁶cfu g^-1 from Dambatta. The Escherichia coli of 3.22 x 10⁶cfu g^-1 recorded in S. scombrus from Dambatta was the highest. All the microbial loads parameters were affected by the species, but not the collection station. The microbial load recorded in this study did not exceed the recommended limit of x10⁶ to 10⁷cfu g^-1 of bacteria load safe for human consumption. The study therefore recommends T. trachurus as the best for consumption in the study area, due to its higher protein composition and the lowest microbial load.

Keywords:
marine fish; frozen; proximate; minerals; microbial loads; free fatty acids

[TFN1] *Values are presented as the means ± standard deviation. *Different small letters as superscripts across the rows indicate significant differences (p<0.05) among the fish species. *Different capital letters as superscripts within the column for each parameter indicate significant differences (p<0.05) among the stations. Key: BCH - Bichi; DBT - Dambatta; GRZ - Gwarzo.

Overall stations and fish species					Two-way ANOVA
Parameters (%)	Stations	C. harengus	S. scombrus	T. trachurus	Species (p value)	Stations (p value)	Species * Stations (p value)
Moisture	BCH	75.59 ± 1.81^a	71.76 ± 1.20^b	69.80 ± 1.05^c	0.000	0.220	0.000
	DBT	74.44 ± 2.53	73.17 ± 0.47	68.66 ± 0.65
	GRZ	73.61 ± 1.77	74.46 ± 0.94	70.19 ± 0.65
Crude protein	BCH	15.28 ± 0.38^c	20.67 ± 1.56^b	20.03 ± 1.58^a	0.000	0.726	0.000
	DBT	18.07 ± 0.48	16.52 ± 1.49	21.51 ± 0.53
	GRZ	17.76 ± 0.64	18.04 ± 1.05	19.66 ± 0.96
Crude lipid	BCH	4.70 ± 1.14^ab	4.07 ± 0.29^b	4.70 ± 0.40^a	0.046	0.106	0.664
	DBT	3.71 ± 1.41	3.93± 0.89	4.44 ± 0.65
	GRZ	4.31 ± 1.13	4.26 ± 0.43	4.84 ± 0.40
Total ash	BCH	2.33 ± 0.15^b	2.31 ± 0.36^b	2.72 ± 0.21^a	0.000	0.623	0.064
	DBT	2.15 ± 0.46	2.45 ± 0.26	2.76 ± 0.11
	GRZ	2.42 ± 0.36	2.18 ± 0.28	2.58 ± 0.22
Carbohydrate	BCH	2.17 ± 0.56^B,b	1.24 ± 0.61^b	2.75 ± 0.54^a	0.000	0.000	0.000
	DBT	1.40 ± 0.95^A	1.91 ± 0.51	2.54 ± 0.55
	GRZ	1.99 ± 0.69^B	1.07 ± 0.79	2.77 ± 0.29
Free fatty acid	BCH	0.92 ± 0.19^A,c	1.27 ± 0.15^b	2.03 ± 0.10^a	0.000	0.000	0.008
	DBT	0.89 ± 0.17^B	0.78 ± 0.12	1.72 ± 0.25
	GRZ	0.87 ± 0.23^C	1.16 ± 0.35	2.07 ± 0.18

Overall stations and fish species					Two-way ANOVA
Parameters (mg Kg^-1)	Stations	C. harengus	S. scombrus	T. trachurus	Species (p value)	Stations (p value)	Species * Stations (p value)
Sodium (Na)	BCH	1.69 ± 0.65^a	0.39 ± 0.07^b	0.50 ± 0.08^b	0.000	0.144	0.008
	DBT	1.44 ± 0.67	0.38 ± 0.07	0.51± 0.08
	GRZ	1.05± 0.66	0.39± 0.05	0.52± 0.09
Calcium (Ca)	BCH	0.12 ± 0.01^b	1.24 ± 0.51^a	0.14 ± 0.03^b	0.000	0.537	0.077
	DBT	0.13 ± 0.04	1.17 ± 0.43	0.14± 0.03
	GRZ	0.15± 0.04	0.95± 0.43	0.15± 0.03
Potassium (K)	BCH	0.64 ± 0.21^a	0.52 ± 0.12^b	0.56 ± 0.14^b	0.004	0.354	0.372
	DBT	0.69 ± 0.19	0.49 ± 0.09	0.58± 0.15
	GRZ	0.70± 0.19	0.58± 0.16	0.61± 0.14
Iron (Fe)	BCH	0.68 ± 0.12^a	0.82 ± 0.43^b	0.63 ± 0.22^b	0.000	0.081	0.000
	DBT	0.93 ± 0.18	0.35 ± 0.28	0.50± 0.05
	GRZ	0.98± 0.09	0.61± 0.17	0.56± 0.13
Manganese (Mn)	BCH	0.23 ± 0.06^c	0.22 ± 0.05^b	0.35 ± 0.03^a	0.000	0.103	0.003
	DBT	0.19 ± 0.06	0.24 ± 0.03	0.39± 0.02
	GRZ	0.18± 0.06	0.28± 0.04	0.41± 0.05

Overall stations and fish species					Two-way ANOVA
Parameters (x10⁶cfu g^-1)	Stations	C. harengus	S. scombrus	T. trachurus	Species (p value)	Stations (p value)	Species * Stations (p value)
Salmonella spp	BCH	0.67 ± 0.50^b	2.00 ± 1.58^b	1.22 ± 0.67^a	0.000	0.060	0.000
	DBT	0.56 ± 0.53	0.78 ± 0.83	4.22 ± 2.54
	GRZ	1.00 ± 1.12	1.22 ± 0.83	1.00 ± 0.87
E. coli	BCH	1. 89 ± 1.05^ab	2.00 ± 1.73^a	1.33 ± 1.00^b	0.037	0.114	0.044
	DBT	1.56 ± 1.13	3.22 ± 1.99	1.11 ± 0.93
	GRZ	1.67 ± 1.12	1.00 ± 0.87	1.11 ± 0.93
Total coliform	BCH	3.67 ± 2.03^A,a	2.11 ± 2.03^ab	1.11 ± 1.17^b	0.003	0.046	0.013
	DBT	1.56 ± 1.01^AB	2.56 ± 2.74	0.67 ± 0.50
	GRZ	2.22 ± 0.71^B	0.33 ± 0.71	1.22 ± 1.30
Mold	BCH	4.89 ± 4.89^a	4.89 ± 1.96^ab	3.56 ± 2.35^b	0.040	0.384	0.283
	DBT	4.22 ± 2.82	3.78 ± 1.99	2.78 ± 1.48
	GRZ	5.78 ± 3.42	2.78 ± 2.44	3.89 ± 1.62