DRAFT ZANZIBAR STANDARD  
 
 
Dried raw seaweed -Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ZANZIBAR BUREAU OF STANDARDS  
 
 
©ZBS 2022 - All rights reserved           First edition  
 
 
 
PCD  435: 202 2 
ICS 67.120.30     
©ZBS 202 2 - All rights reserved  
 ii 
 Foreword  
 
 
 
 
This draft Zanzibar  National  Standard has been developed Fish and fisheries, meat, poutry and their 
products  Standard Technical committee (TCFA 6). In accordance with ZBS general procedures, this draft 
standard is presented to the public in order to receive any technical and editorial comment concerns.  
 
The Zanzibar Bureau of Standard (ZBS) was established under Standard Act No. 1 of 2011.   
 
 
In the preparation of this Standard, the reference was derived from:  PNS/BAFPS 85:20 12 Dried Raw 
Seaweed – Specification   
 
 
Zanzibar Bureau of Standards (ZBS)  
PO Box 1136  
Zanzibar  
Tel:  +255 24 2232225  
Fax: +255 24 2232225  
E-mail: info@zbs.go.tz  
Web: www.zbs.go.tz  
 PCD  435: 2022  
 
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 Dried raw seaweed - Specification  
 
1 Scope  
This draft standard specifies requirements, method of sampling and test of dried  raw seaweeds of the 
class Rhodophyceae (red seaweed) such as , but not limited to Cottonii ( Kappaphycus spp.) and 
Spinosum ( Eucheuma spp) intended for human consumption  or for  industrial use.  
2 Normative refe rences  
The following referenced documents are indispensable for the application of this draft Zanzibar National 
Standard. For dated references, only the edition cited applies. For undated references, the latest edition 
of the referenced document (including  any amendments) applies.  
 
AOAC 952.13, Arsenic in food — Silver diethyldibocarbamate method  
 
AOAC 972.23, Lead in fish —– Atomic absorption spectrophotometric method  
 
 AOAC 973.34, Cadmium in food — Atomic absorption spectrophotometric method  
 
AOAC 983.20, Mercury (methyl) in fish and shellfish — Gas chromatographic method  
 
CODEX STAN 193, Codex general standard for contaminants and toxins in food and feed  
 
ZNS 61 , Packaging and labeling of food  
 
ZNS 94, Rounding off numerical values  
 
TCD 437 Code of  aquaculture practices for seaweed  
 
CXC 52 , Code of practice for fish and fishery products  
 
3 Terms and definitions  
For the purposes of this Standard, the following (terms and) definitions shall apply.  
3.1  
seaweed  
cluster of macroscopic, multicellular, benthic marine algae ; includes some members of the red, brown 
and green algae  
 
3.2  
dried raw seaweed  
seaweed  obtained by the removal of water through  sun/solar dried or artificial means  
  
3.3  
rhodophyceae  
class of red seaweed  such as but not limited to Cottonii ( Kappaphycus spp .) and Spinosum ( Eucheuma 
spp) 
 
3.4  
cottonii  
seaweed of the Kappaphycus spp.  of class Rhodophyceae  
 
3.5  
spinosum  
seaweed of the Eucheuma spp. of class Rhodophyceae  
 
3.6  PCD  435: 2022  
 
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 clean anhydrous seaweed (CAS)  
seaweed removed of moisture, salt, sand and impurities.  
3.7  
contaminants  
any biological or chemical agent, foreign matter, or other substances not intentionally added to dried 
raw seaweed which may comprom ise food safety and suitability  
3.8  
impurities/debris  
other type of seaweed, plastic, wood, shells, d irt and other foreign matters other than sand and salt.  
3.9  
adulteration  
addition of any other substances to dried raw seaweed in order to increase the quantity, in raw form or 
prepared form, which results in the loss of actual quality of dried raw seaweed  
3.10  
food grade material  
material  which shall safeguard the hygienic, safety, nutritional, technological, and organoleptic qualities 
of the product  
4 Requirements  
4.1 General requirements  
 
Dried raw seaweed shall  
 
a) be of one species only;  
b) be mature, having a culture period of at least forty-five (45)  days ; 
c) be visibly  free from diseases such as epiphyt ism and ‘ice ice’; and  
d) having variation  in colour ; of either red, purple, green , and brown  
4.2 Specific requirements  
 
Dried raw seaweed  shall be classified into three grades  on the basis of the specific requirements given  
in Table 1 when tested in accordance with test methods specified therein.  
 
Table 1 : Specific requirements  for dried raw seaweed  
S/No  Characteristics  Requirement  Test methods  Grade A  Grade B  Grade C  
i.  Clean anhydrous seaweed 
(CAS), (%)  min 90 80 70 Annex A  
ii.  Sand, (%)  max 1 Annex B 
iii.  Impurities, (%)  max 3 Annex C 
iv.  Moisture content (MC),                 
(%) max 
  
Cottonii  
 
Spinosum  
  
 
 
35 
 
30 
 Annex D 
v.  Salt as KCl,  (%) max 
 
Cottonii  
 
Spinosum  
  
 
25 
 
20 Annex B 
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 5 Additives  
Dried raw seaweed shall be free from any additives . 
6 Adulteration  
Dried raw seaweed shall be free from any adulterants such as sand, water and chemicals . 
7 Contaminants  
7.1 Heavy Metal contamination  
 
Dried raw seaweed shall comply with those maximum heavy metal limits given in Table 2 when tested 
in accordance with test methods specified therein.  
Table 2: Maximum limits for heavy metal contaminants in dry raw seaweed  
 
S/N  
Parameter Maximum 
limit  
mg/kg  
Test method 
i.  Arsenic  (As) 3 AOAC  952.13  
ii.  Lead (Pb)  5 AOAC  972.23  
iii.  Mercury  1 AOAC  983.20  
iv.  Cadmium ( Cd) 1 AOAC  973.34  
 
7.2 Pesticide residues  
 
Dried raw seaweed shall comply with those pesticide maximum residues limits established in the Codex 
pesticide residues in food online data base  and/or competent authority for this commodity .  
8 Hygiene  
Dried raw seaweed shall be produced, transported and /or distributed in accordance with requirements 
set according to TCD 437  and CXC 52  
9 Weights and measures  
Dried raw seaweed shall be packed in accordance with the weights and measures regulations of 
Zanzibar . 
 
10 Packaging and Labelling  
 
10.1 Packaging  
 
Dried raw seaweed shall be packaged in food grade material that secures the integrity and the safety of 
the product.  
 
10.2 Labelling   
 
10.2.1  In addition to the labelling requirements specified in ZNS 61, the containers shall be also legibly 
and indelibly labelled with the following: - 
 
a) name of the product  as ‘Dried raw seaweed’ ; 
b) species name ; 
c) brand name/trade name  if any ;  
d) name and address of producer/packer/distributor;  PCD  435: 2022  
 
©ZBS 202 2 - All rights reserved  
 6 
 e) storage condition and transportation;  
f) date of packing ; 
g) best before date;  
h) lot identification or batch or code number;  
i) country of origin;  
j) net weight in metric unit; and  
k) instruction for disposal of used packaged material.  
10.2.2  The language on the label shall be ‘Kiswahili’ and/or English. Additional language may be used 
depending on the designated market.  
 
11 Sampling  
Sampling of dried raw seaweed shall be done according Annex E.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 Annex A 
(Normative)  
Determination of  clean anhydrous seaweed (CAS)  
 
 
Percent Clean Anhydrous Seaweed is obtained by the formula:   
 
                    
%𝐶𝐴𝑆 =CAS
Wο×100  
 
where:  
 
CAS is the mass of clean anhydrous seaweed in grams  
Wo is the original mass of seaweed taken for analysis in grams  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 Annex B 
(normative)  
Determination of salt (as KCl) and sand  
 
D.1 Determination of  salt as KCl  
 
D.1.1  Get a one (1) kilogram representative sample of the  dried  raw seaweed material;  
 
D.1.2  Weigh 250 g into a 2 -L beaker;  
 
D.1.3  Add about 900 ml of distilled water, soak the seaweed overnig ht to remove the sand and salt. 
Remove the seaweed, stir the solution very well to completely dissolve the salt;  
 
D.1.4  Decant the solution into a 1 -L volumetric flask and dilute to volume dis tilled water. Save the 
sand for further analysis;  
 
D.1.5  Mix the solution well and measure a 50 ml aliquot into a 250 -ml volumetric flask;  
 
D.1.6  Dilute to volume with distilled water. Mix well and measure a 10 ml aliquot into an Erlenmeyer 
flask;  
 
D.1.7  Add 5 drops of K 2CrO4 and titrate with standard 0.100 N AgNO 3 to end point (tinge of orange 
brown);  
 
D.1.8  Calculate % salt (as KCl) using the following formula:  
 
% salt (as KCl)= 𝑉 Ag𝑁𝑂 3×𝑁 Ag𝑁𝑂 3×74.50
1000
250 ×50
1000×10
250   ×100 
 
 
D.2 Determination of sand 
 
D.2.1  Wash the sand from step D.1.4  with distilled water 3 times;  
 
D.2.2  Put the sand into a pre -weighed porcelain crucible;  
 
D.2.3  Dry in the oven at 105oC to constant mass. Record weight as W d; and  
 
D.2.4  Calculate % sand using the following formula:  
 
% sand = 𝑊𝑑
250 ×100 
where:  
Wd is the weight of the dried sand in grams  
 
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 Annex C  
(normative)  
Determination of impurities/debris  
 
C.1 Weigh 250 grams laboratory sample. Record weight as Wo; 
 
C.2 Remove debris and other foreign material by hand.  
 
C.3 Weigh the impurities/ debris and other foreign materials. Record weight as W D; and  
 
C.4 Calculate Percent Impurities/Debris by the formula:  
 
 
% 𝐼𝑚𝑝𝑢𝑟𝑖𝑡𝑖𝑒𝑠 /𝑑𝑒𝑏𝑟𝑖𝑠 =𝑊𝐷
𝑊𝑂×100 
 
where:  
 
WD is the mass of debris/impurities and other foreign materials in grams  
WO is the mass of laboratory sample taken for analysis in grams  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 Annex D 
(normative)  
Determination of moisture of seaweed  
 
A.1 Method A – Determine moisture of seaweed by direct reading using the moisture meter.  
 
A.2  Method B – Oven Drying  
 
A.2.1  Apparatus:  Thermally controlled drying oven  
 
A.2.2  Procedure:  
 
a) Weigh one hundred grams of seaweed laboratory sample in a pre -weighed moisture dish. 
Record weight as Wo ; 
 
b) Dry dish plus sample to constant mass at a temperature of 60°C -65°C for Eucheuma spp. and 
80°C-85°C for Kappaphycus spp. in 12 to 16 hours. Record weight as Wf ; and  
 
c) Calculate Percent Moisture using the following formula:  
 
% 𝑀𝑜𝑖𝑠𝑡𝑢𝑟𝑒 =Wο−W𝑓
Wο×100 
 
where:  
Wf is the weight of the seaweed after drying  
Wo is the weight of the seaweed before  drying  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 Annex E  
(normative)  
Sampling  
 
E.1  Definition of terms  
 
E.1.1   
bulk sample  
quantity of dried raw seaweed obtained by combining and mixing the primary sample taken from a 
specific lot.  
 
E.1.2   
consignment  
quantity of dried raw seaweed dispatched or  received at one time and covered by a particular contract 
or shipping document. It may be composed of one or more lot.  
 
E.1.3   
laboratory sample  
quantity of dried raw seaweed removed from the bulk sample and is intended for analyses or other 
examination.  
 
E.1.4   
lot   
composed of dried raw seaweed belonging to the same species intended to be uniform in characteristics 
regarding post harvest treatment.  
 
E.1.5   
primary sample  
a small quantity of dried raw seaweed taken from a bag/bale from a lot.  
 
E.2 Sample size  
Sampling shall be done in accordance with the plan specified in Table E.1. 
Table E.1: Sampling plan for dried raw seaweed  
Lot size (N)  Size of the sample (n)  
1 to 5 bags/bales  All bags/bales  
6 to 49 bags/bales  5 bags/bales  
50 to 199 bags/bales  10% of the bags/bales  
200 bags/bales or more  √𝑛+ 1 
 
Where  n =  number of bags/bales  
 
E.3 Sampling procedure  
The sample shall be taken at random from the lot and in order to achieve this, a random number table 
agreed upon between the buyer and seller should be used.  If such table is not available, the following 
procedure shall be adopted:  
  
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a) Starting from any bag/bale, count the bags/bales as 1, 2, 3… etc. up to r and so on. Withdraw 
from the lot every rth bag/bale thus counted for sampling, the value of r is equal to 
𝑟=𝑁
𝑛 
where:  
 
N is the total number of bags/bales in the lot;  
n is the number of bags/bales to be taken (see Table E.1) 
 
b) If r is a fractional number, its value shall be taken as equal to the integral part of it.  
 
 
E.3.1  When the product is in movement, samp les may be taken at the time of loading or unloading of 
the bags/bales. For this purpose, the number of bags/bales to be taken shall also be in accordance with 
Table 2. The value of r shall be calculated as indicated above, and every rth bags/bales counted  during 
loading or unloading shall be removed for sampling.  
 
E.3.2  Take primary samples, by means of an appropriate sampling instrument, from different parts of 
each bags/bales selected.  
 
E.3.3  A series of primary samples should be taken from different positions in the lot.  
 
E.4 Bulk sample  
 
E.4.1  Thoroughly mix all the primary samples taken as described above to form the bulk sample.  
 
E.4.2  The size of the bulk sample shall be more than three (3) times the quantity of sample required 
to carry out all the tests required in the speci fication.  
 
E.5 Laboratory samples  
 
E.5.1  Divide the bulk sample into three (3) or more equal parts. Each part thus obtained constitutes a 
laboratory sample; one (1) of these samples is intended for the buyer and another for the seller. The 
third sample, bearing the seals of the buyer and of the seller (or of their representatives) if they were 
present at the time of sampling or of the person who sampled the lot, shall constitute the reference 
sample to be used in case of dispute between buyer and seller; it shall be kept at a place acceptable to 
both parties.  
 
E.5.2  Samples for test shall be one (1) kilogram.