ICS 67.120.30           DMS 115:2018  
Second  edition  
 
 
 
 
DRAFT MALAWI STANDARD  
(SADC HARMONIZED)  
 
 
 
 
 
 
 
 
 
 
 
Fresh and frozen whole fin fish – 
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Note: This is a draft standard and it shall neither be used nor  regarded as a Ma lawi standard   
 
 ICS 67.120.30                  DMS 115:2018 
             Second edition  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fresh and frozen whole fin fish – 
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
Obtainable from the  
Malawi Bureau of Standards  
Moirs Road  
P O Box 946  
BLANTYRE  
 
Tel: +265 1 870 488  
Fax: +265 1 870 756  
E-mail: mbs@mbsmw.org  
Website: www.mbsmw.org  
Price based on 7 page s 
© Copyright reserved   
i 
 TABLE OF CONTENTS  
 
Contents                                                                                                                                                      Page  
 
Foreword  ................................ ................................ ................................ ................................ ..............................  i 
Technical Committee  ................................ ................................ ................................ ................................ ...........  i 
Notice  ................................ ................................ ................................ ................................ ................................ ... i 
Scope  ................................ ................................ ................................ ................................ ................................ . 1 
Normative references  ................................ ................................ ................................ ................................ ........  1 
Definitions  ................................ ................................ ................................ ................................ ..........................  2 
Essential  composition and quality factors ................................ ................................ ................................ .........  3 
Food additives  ................................ ................................ ................................ ................................ ...................  3 
Contaminants  ................................ ................................ ................................ ................................ .....................  3 
Hygiene  ................................ ................................ ................................ ................................ ..............................  4 
Packaging and labeling ................................ ................................ ................................ ................................ ...... 4 
Methods of sampling and tests  ................................ ................................ ................................ ..........................  5 
Annex A; Determination of histamine  ................................ ................................ ................................ ................  6 
 
FOREWORD  
 
This draft standard  is a Southern African Development Community  (SADC)  Harmonized Text covering the 
requirements and methods of tests for fresh and frozen whole fin fish.  
  
The harmonization of standards and technical regulations in the SADC  region is an obligation under the 
SADC protocol on Trade which was established under the SADC Treaty to  provide for elimination of tariffs 
and non -tarriff barriers  to trade.  
 
This draft standard is ide ntical to SADC HT 81, Fresh and frozen whole fin fish  – Specification.  
   
Acknowledgement is made fo r the use of the above standard . 
 
 
TECHNICAL COMMITTEE  
 
This draft standard was prepared by the Technical Committee MBS/TC 39, Fish and fishery products,  and 
the following companies, organizations and institutions were represented:  
 
Malawi Bureau of Standards.  
MALDECO Fisheries  
Malawi College of Fisheries;  
Ministry of Agriculture, Irrigation and Water Development – Department of Fisheries;  
Lake Harvest;  
Lilongwe University for Agriculture and Natural Resources;  
 
NOTICE  
 
This standard shall be reviewed every five years, or earlier when it is necessary, in order to keep abreast of 
progress. Comments are welcome and shall be considered when the standard is being reviewed .  
1 
                 DMS 115: 2018 
 
DRAFT MALAWI STANDARD  
 
Fresh and frozen whole fin  fish - Specification  
 
1 SCOPE  
 
This draft standard specifies requirements and methods of sampling and test for fresh and frozen whole fin 
fish intended for human consumption . 
 
 
2 NORMATIVE REFERENCES  
 
The following standard  contain s provisions, which through reference in this text, constitute pro visions of this 
draft standard.  All standards are subject to revision  and, since any reference to a standard is deemed to be a 
reference to the latest edition of that standard, parties to agreements based on this draft standard  are 
encouraged to take steps  to ensure the use of the most recent edition of the standard indicated below. 
Information on current valid national and international standards can be obtained from the Malawi Bureau of 
Standards.  
 
MS 19:  Labelling of prepacked foods – General standard;  
 
MS 21:  Food and food processing units – Code of hygienic conditions;  
 
MS 188: Edible salt – Specification;  
 
MS 214:  Potable water – Specification ; 
 
MS 237:  Food additives – General Standard;  
 
MS 302:  General  standard  for contaminants and toxins in foods  and feed;  
 
MS 790: Code of practice for fish and fishery products;  
 
MS 1241:  Guidelines for the sensory evaluation of fish and shellfish in laboratories ;  
 
CODEXSTAN  233: Sampling plans for prepackaged foods (AQL -6.5); 
 
ISO 4833 : Microbiology of food and animal feeding stuffs – Horizontal method for the enumeration of 
microorganisms – Colony -count technique at 30 degrees;   
 
ISO 6579:  Microbiology of food and animal feeding stuffs – Horizontal method for the detection of Salmonella 
spp.;  
 
ISO 6888:  Microbiology of food and animal feeding stuffs – Horizontal method for the enumeration of 
coagulase -positive staphylococci (Staphylococcus aureus and other species) ; 
 
ISO 7251:  Microbiology of food and animal feeding stuffs – Horizontal method for the detection and 
enumeration of presumptive Escherichia coli – Most probable number technique;  
  
ISO 793 7: Microbiology of food and animal feeding stuffs – Horizontal method for the enumeration of 
Clostridium perfringens – Colony -count technique;  
 
ISO 11290 : Microbiology of the food chain – Horizontal method for the detection and enumeration of Listeria 
monocytogenes and of Listeria spp. ; 
 
ISO 16050: Foodstuffs –  Determination of aflatoxin B1, and the total content of aflatoxin B1, B2, G1 
and G2 in cereals, nuts and derived products –  High performance liquid chromatographic method; 
  
2 
  
ISO 21527-1: Microbiology of food and animal feeding stuffs – Horizontal  method for the e numeration of  
yeasts and moulds – Part 1: Colony count technique in products  with water activity great er than 0.9; 
 
ISO/TS 21872 -1: Microbiology of food and animal feeding stuffs – Horizontal  method for the detection of 
potentially enteropathogenic Vibrio spp. – Part 1: Detection of Vibrio parahaemolyticus and Vibrio  cholera;  
and 
 
ISO/TS 21872 -2: Microbiology of food and animal feeding stuffs – Horizontal  method for the detection of 
potentially enteropathogenic Vibrio spp. – Part 2: Detection of species other than Vibrio parahaemolyticus 
and Vibrio cholera ;  
 
ISO 27085: Animal feeding stuffs – Determination of calcium, sodium, phosphorus, magnesium, 
potassium, iron, zinc, copper, manganese, cobalt, molybdenum, arsenic, lead and cadmium by ICP- AES 
 
AOAC   990.04:   Mercury   (Methyl)   in   sea   food   by   liquid   chromatography-Atomic A b s o r p t i o n  
Spectroscopy (LC-AAS); and 
 
AOAC 977.15 / 974.14: Mercury in fish by Flame Atomic Absorption Spectroscopy (FAA). 
 
 
3 DEFINITIONS  
 
For the purpose of this draft standard , the following definitions shall apply:  
 
3.1  
fresh  fin fish 
fish that has not been frozen, dried or otherwise preserved, except by chilling including f ish in rigor 
 
3.2  
food grade  
packages which safeguard the hygienic, nutritional, technological and organoleptic qualities of the products  
 
3.3  
gutted fish  
fish from which the guts have been removed. Gutting consists of bleeding the fish and removal of the 
stomach and gut 
 
3.3 
rigor mortis  
the stiffening of the muscles of fish which results from a series of complex changes that take place in the 
tissues shortly after death 
 
3.4 
fin fish  
fresh water and marine vertebrate fish 
 
3.5 
whole fish  
fish as captured, ungu tted 
 
3.6  
chilling  
The process of cooling fish to a temperature approaching that of melting ice (0 ºC to 4 ºC)  
 
3.7 
clean water  
water  which meets the same microbiological standards as potable water and is free from  
objectionable substance. 
 
 
  
3 
 3.8  
frozen fish  
fish that has been subjected and maintained at temperatures of -18 ºC or lower 
 
 
4 ESSENTIAL COMPOSITION AND QUALITY FACTORS  
 
4.1 General req uirements 
 
Fresh and frozen finfish may be presented as uneviscerate d, eviscerated, and shall; 
 
4.1.1  be in a sound, who lesome condition; 
 
4.1.2  be bright in appearance ; 
 
4.1.3  have a fresh char acteristic smell of its species;  
 
4.1.4  have prominen t, bright, clear and moist eyes  
 
4.1.5  have  bright red gills;  
 
4.1.6  have bright abdominal blood;  
 
4.1.7  be fir m, and shall have elastic flesh;  
 
4.1.8  have scales which adhere strongly t o the skin where this is normal;  
 
4.1.9  be free from diseases and parasites; and  
 
4.1.10  Where  present on fresh fish; slime shall be transparent . 
 
4.2 Specific requirements 
 
4.2.1  Fresh fish shall be stored at chilling temperature ; 
 
4.2.2  Frozen fish shall be maintained at a temperature of -18 ºC or lower ; and  
 
4.2.3  When tested as per annex A the level of histamine in species with high levels of histidine such as 
scromboids shall not exceed 10  ppm.  
 
4.3 Microbiological limits  
 
The product shall comply with microbiological limits given in Table 1. 
 
Table 1:  Microbiological limits for fresh  and frozen  whole fin fish  
 
S/No Micro-organisms  Max. limits Method of test 
i)  Salmonella per 25 g Absent ISO 6579 
ii)  E. coli per gram Absent ISO 7251 
iii)  Listeria monocytogenes Absent ISO 11290 Part 1 
iv)  Staphylococcus aureus  cfu per gram 102 ISO 6888 
v)  Clostridium perfringens per gram Absent ISO 7937 
vi)  Vibrio Spp per gram  Absent ISO 21872 
vii)  Total viable count per gram 105
 ISO 4833 
 
 
  
4 
 6 FOOD ADDITIVES  
 
If used, food additives shall comply with  MS 237.  
 
 
7 CONTAMINANT S  
 
Fresh and frozen whole fin fish  shall conform to those maximum levels for heavy metals and other 
contaminants as stipulated in MS 302 . 
 
 
8 HYGIENE  
 
8.1  The products covered by the provisions of this draft standard shall be prepared and handled in 
accordance with the appropriate sections of the MS 21 and 790.  
 
8.2 The final product shall be free from any foreign material that poses a threat to human health.  
 
 
9 PACKAGING AND LABELLING  
9.1 Packaging  
 
Fresh an d frozen whole fin fish  shall be packaged in food grade containers.  
9.2 Labelling  
 
In addition to the requirements in MS 19, the following specific labelling requirements shall apply and shall 
be legibly and indelibly marked: 
 
9.2.1  Name of the product shall be "Fresh or frozen fin fish”; 
 
9.2.2  Storage and transportation conditions declaring the temperature to be -18 ºC or lower; 
 
9.2.3  Name and physical address of processor; 
 
9.2.4  Net weight in metric units ; 
 
9.2.5  Date of production ; 
 
9.2.6  Batch or code number;  
 
9.2.7  Expiry date; and  
 
9.2.8  Country of origin and/or water body . 
 
9.3 Labelling of n on-retail containers  
 
Information on the above provisions shall be given either on the container or in accompanying documents, 
except that the name of the product, lot identification, and the name and  address of the processor or 
packer as well as storage instructions, shall appear on the container.  
 
However, lot identification, and the name and address of the processor or packer may be replaced by an 
identification mark provided that such a mark is cle arly identifiable with the accompanying documents.  
  
10 METHOD OF  SAMPL ING AND TE ST 
 
Sampling and tests shall be done as per test methods described in respective tables in this draft standard . 
  
5 
 ANNEX A  
 
(Normative)  
 
DETERMINATION OF HISTAMINE  
 
A.1 PRINCIPLE  
 
Sample is extracted with 75  % (v/v) methanol. Extract is pass ed through ion exchange column.                     
o– Phthaldialdehyde solution is added to eluate to form fluorescent histamine derivatives. Fluorescent 
intensity of derivatives is measured us ing fluorometer and histamine is quantified using external standards.  
 
A.2 APPARATUS  
 
Rinse all plastic and glass containers with HCl (1 + 3) and H 2O before use.  
 
A.2.1  Chromatographic tube  - 200   7 id mm polypropylene tube fitted with small plastic stopc ocks and ca                 
45 cm Teflon tubing. Control flow rate at >3 ml/min by adjusting height of column relative to tubing outlet. 
Alternatively, use 2 -way valve in place of tubing.  
 
A.2.2  Photofluorometer  - equipped with medium pressure Hg lamp with excitation at 350 nm and 
measuring emission at 444 nm.  
 
A.2.3  Pipettes  - 1 and 5 ml  
 
 
A.3 REAGENTS  
 
A.3.1  Ion-exchange resin , Bio-Rad AG 1 - X 8, 50  – 100 mesh or Dowex 1 - X 8, 50  – 100 mesh.  Convert 
to -OH form by adding ca 15 m 2  M NaOH/g resin to beaker. Swirl mixture and let stand  < 30 min. Decant 
liquid and repeat with additional base. Thoroughly wash resin with H 2O, slurry into fluted paper and wash 
again with H 2O. Prepare resin fresh weekly and store under H2O. Place glass wool plug in base of tube, 
A.2.1, and slurry in enough resin to form 8 cm bed.  Maintain H 2O level above top of resin bed at all times. Do 
not regenerate resin in packed column; rather, use batch regeneration in beaker when necessary. Wash 
column with about 10 ml H 2O before applying each extract.  
 
A.3.2  Phosphoric acid , 3.57 N. Dilute 121.8 ml 85  % H 3PO 4 to 1 litre. For other concentration H 3PO 4, 
volume required for 1 litre 1.19 M acid = 17493/ (density H 3PO 4 percent H 3PO 4). Standardize  5.00 ml by 
titration with 1.00  M NaOH to phenolphthalein end point, and adjust concentration if necessary.  
 
A.3.3  O-Phthaldialdehyde (OPT) solution , 0.1 % (w/v).  Dissolve 100 mg OPT in 100 ml distilled -in- glass 
methanol. Store in amber bottle in refrigerator.  Prepare fresh weekly.  
 
A.3.4  Histamine standard solutions. Store in refrigerator.  
 
A.3.4.1  Stock solution,  1 mg/ml as free base. Accurately weigh ca 169.1 mg histamine 2  HCl (98  %) into 
100 ml volumetric flask, and dissolve and dilute to volume with 0.1M HCl. Prepare fresh weekly.  
 
A.3.4.2  Intermediate solution,  10 µg/ml. Pipet 1 ml stock solution into 100 ml volumetric flask, and dilute to 
volume with 0.1M HCl. Prepare fresh weekly.  
 
A.3.4.3  Working solutions , 0.5, 1.0, and 1.5 µg/5 ml. Pipet 1, 2, and 3  ml intermediate solution into 
separate 100 ml volumetric flasks, and dilute each to volume with 0.1  M HCl. Prepare fresh daily.  
  
A.3.5  Methanol , 75 % (v/v).  Place 75 ml MeOH (distilled in glass) into 100 ml volumetric flask or stoppered  
graduated cylinder. Dilute to volume with H 2O. Swirl flask while adding H 2O. 
 
 
A.4 PREPARATION OF STANDARD CURVE  
 
Pipet duplicate 5 ml aliquots of each working standard solution into separate 50 ml glass or polypropylene 
Erlenmeyers. Pipet in 10 m l 0.1 M HCl to each flask and mix. Pipet in 3 ml 1  M NaOH and mix. Within 5 min,  
6 
 pipet in 1 ml OPT solution and mix immediately. After exactly 4 min, pipet in 3 ml 3.57  NH 3PO 4 and mix 
immediately.  It is important to mix thoroughly after each addition and at least once during OPT reaction. (Run 
6 – 10 OPT reactions simultaneously by adding reagents to Erlenmeyers in set order.) Prepare blank by 
substituting 5 ml 0.1  M HCl for histamine solution. Wit hin 1.5 h, record fluorescence intensity (I) of working 
standard solutions with H 2O in reference cell, using excitation wavelength of 350 nm and emission 
wavelength of 444 nm. Plot I (corrected for blank) against µg histamine/5 ml aliquot.  
 
 
A.5 DETERMINAT ION 
 
A.5.1  Extract prepared sample with 75  % (v/v) methanol. Pass 4  – 5 ml H 2O through column, A.2.1 and 
discard eluate. Pipet 1 ml extract onto column and add 4  – 5 ml H 2O. Immediately initiate column flow into  
50 ml volumetric flask containing 5.00 ml 1.00M HCl. When liquid level is ca 2 mm above resin, add ca 5 ml 
H2O and let elute. Follow with H 2O in larger portions until ca 35 ml has eluted. Stop column flow, dilute to 
volume with H 2O, stopper, and mix. Refrige rate eluate.  
 
A.5.2  Pipet 5 ml eluate into 50 ml Erlenmeyer, and pipet in 10 ml 0.1  M HCl. Proceed as in A.4, beginning  
"Pipet in 3 ml 1  M NaOH….”  
 
A.5.3  If test sample contains >15 mg histamine/100 g fish, pipet 1 ml sample –OPT mixture into 10 ml 
beaker c ontaining exactly 2 ml blank –OPT mixture, and mix thoroughly. Read fluorescence of new solution. 
Dilute and mix aliquots with blank –OPT mixture as needed to obtain measurable reading. This approximation 
indicates proper dilution of eluate required prior to  second OPT reaction needed for reliable quantitation of 
test sample. Alternatively, use sensitivity range control of fluorometer (if instrument has one) to estimate 
dilution. Use these approximations to prepare appropriate dilution of aliquot of eluate wi th 0.1NHCl, and 
proceed as in A.4, beginning "Pipet in 3 ml 1  M NaOH"  
 
 
A.6 CALCULATIONS  
 
A.6.1  Plot of I (measured by meter deflection or recorder response and corrected for blank) against                                 
µg histamine/ 5 ml test solution should be straight line passing through origin with slope = m = [(Ia /1.5) + Ib + 
2Ic ]/3. mg Histamine/100 g fish = (10)(F)(1/m)(Is)  
 
µg Histamine/g fish = 10  (mg histamine/100 g fish)  
 
where Is, Ia, Ib, and Ic  = fluorescence from test sample, 1.5, 1.0, and 0.5 µg histamine standards, 
respectively; and F = dilution factor = (ml eluate + ml 0.1M HCl)/ml eluate. F = 1 for undiluted eluate.  
 
A.6.2  If calibration plot is not linear, use standard curve directly for quantitation. Each subdivision on  
abscissa sh ould be ≤  0.1 µg histamine/5 ml test solution. Read all values from curve to nearest 0.05  µg 
histamine/5 ml test solution.  
 
mg Histamine/100 g fish = (10)(F)(W)  
 
µg Histamine/g fish = 10× (mg histamine/100 g fish)  
 
where W = µg histamine/5 ml test solution  as determined from standard curve.   
1 
 
 
 
 
ICS 6 7.120.30                  DMS 115:2018 
    Second  edition  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
THE MALAWI BUREAU OF STANDARDS              CERTIFICATION MARK SCHEME  
The Malawi Bureau of Standards is the 
standardizing body in Malawi under the aegis 
of the Ministry of Industry and Trade .  Set up 
in 1972 by the Malawi Bureau of Standards 
Act ( Cap: 51:02), the Bureau is a parastatal 
body whose activities aim at formulating and 
promoting the general adoption of standards 
relating to structures, commodities, materials, 
practices, operations and from time to time 
revise, alter and amend the same to  
incorporate advanced technology.  To bring the advantages of standardization 
within the reach of the common consumer, the 
Bureau operates a Certification Mark Scheme. 
Under this scheme, manufacturers who 
produce goods that conform  to national 
standards are granted permits to use the 
Bureau’s “Mark of Quality” depicted below on 
their products.  This Mark gives confidence to 
the consume r of the commodity’s reliability