AFRICAN 
STANDARD  CD-ARS  
1132-3 
First Edition 2023 
 
 Reference No. CD-ARS 1132-3:2023(E) 
ICS 67.120.30  
 
 
© ARSO 20 23 
 
 
 
 
 
 
 
 
 
 
 
Test methods for fish and fishery products — Part 3: Determination 
of parasites in finfish by candling  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CD-ARS  1132-3:2023 
ii © ARSO 20 23 — All rights reserved   
Table of contents  
 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ .....................  1 
3 Equipment and materials  ................................ ................................ ................................ ................  1 
4 Sample preparation  ................................ ................................ ................................ ........................  1 
Bibliography  ................................ ................................ ................................ ................................ ............  5 
 
  CD-ARS 1 132-3:2023 
© ARSO 20 23 — All rights reserved  iii Foreword  
 
The African Organization for Standardization (ARS O) is an African intergovernmental organization 
established by the United Nations Economic Commission for Africa (UNECA) and the Organization of 
African Unity (AU)  in 1977 . One of the fundamental mandates of ARSO is to develop and harmoniz e 
African Standard s (ARS) for the purpose of enhancing Africa’s internal trading capacity, increase 
Africa’s product and service competitiveness globally and uplift the welfare of African communities.  The 
work of preparing African  Standards is normally carried out through ARSO  technical committees. Each 
Member State  interested in a subject for which a technical committee has been established has the 
right to be represented on that committee. International organizations, Regional Economic Communities 
(RECs), governmental and non-governmental  organizations , in liaison with ARSO , also take part in the 
work.  
 
ARSO  Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.  
 
The main task of technical committees is to prepare ARSO  Standards. Draft ARSO  Standards adopted 
by the technical committees are circulated to the member bodies for voting. Publication as an ARSO  
Standard requires approval by at least 75 % of the member bodies casting a vote.  
 
Attention is drawn to the possibility that some of the elements of this document may be the subject of 
patent rights. ARSO  shall not be hel d responsible for identifying any or all such patent rights.  
 
This African Standard was prepared by ARSO/TC 03, Fish, fisheries and aquaculture . 
 
 
 
 
 
© African Organisation for Standardisation  2023 — All rights reserved* 
 
ARSO Central Secretariat  
International House 3rd Floor  
P. O. Box 57363 — 00200 City Square  
NAIROBI, KENYA  
 
Tel. +254 -20-2224561, +254 -20-3311641, +254 -20-3311608  
 
E-mail: arso@arso -oran.org  
Web: www.arso -oran.org  
  
 
* © 2022 ARSO — All rights of exploitation reserved worldwide for African Member States’ NSBs.  CD-ARS  1132-3:2023 
iv © ARSO 20 23 — All rights reserved   
Copyright notice  
 
This ARSO document is copyright -protected by ARSO. While the reproduction of this document 
by participants in the ARSO standards development process is permitted without prior permission 
from ARSO, neither this document nor any extract from it may be reproduced, sto red or 
transmitted in any form for any other purpose without prior written permission from ARSO.  
 
Requests for permission to reproduce this document for the purpose of selling it should be 
addressed as shown below or to ARSO’s member body in the country of  the requester:  
 
 
© African Organisation for Standardisation 20 23 — All rights reserved  
 
ARSO Central Secretariat  
International House 3rd Floor  
P.O. Box 57363 — 00200 City Square  
NAIROBI, KENYA  
 
Tel: +254 -20-2224561, +254 -20-3311641, +254 -20-3311608  
 
E-mail: arso@arso -oran.org  
Web: www.arso -oran.org  
 
Reproduction for sales purposes may be subject to royalty payments or a licensing agreement. 
Violators may be p rosecuted.  
 
 
 
  CD-ARS 1 132-3:2023 
© ARSO 20 23 — All rights reserved  1  
Test methods for fish and fishery products — Part 3: Determination 
of parasites in finfish by candling  
 
1 Scope  
 
This draft African standard specifies the method of test for determination of parasites  in fish and fishery 
products  by candling. This applies to  white flesh processed as fillets, loins steaks, chunks or minced  
 
2 Normative references  
 
The following referenced documents are indispensable for the application of this document. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
 
CAC/GL 21, Principles for the establishment and application of microbiological criteria for foods  
 
CAC/RCP 1, Recommended international code of practice — General principles of food hygiene  
 
CAC/GL 30, Principles and guidelines for the conduct of microbiological risk assessment  
 
CAC/GL  31, Guidelines for the sensory evaluation of fish and shellfish in laboratories  
 
CAC/GL 48, Model certificate for fish and fishery products  
 
CAC/RCP 52:2003 Code of practice for fish and fishery products  
 
CAC/GL 53, Guidelines on the judgement of equivalence of sanitary measures associated with food 
inspection and certification systems  
 
ARS 56, Labelling of pre-packaged  foods — Specification  
 
3 Equipment and materials  
 
3.1 Sharp knife 
 
3.2 Candling table — Rigid framework to hold light source below rigid working surface of white, 
translucent acrylic plastic or other suitable material with 45 -60 per cent translucency. Length and width 
of working surface should be large enough to permit examination of entir e fillet, e.g ., 30 × 60 cm sheet, 
5-7 mm thick.  
 
3.3 Light source  — “Cool white” with color temperature of 4200 K. At least two 20 -watt fluorescent 
tubes are recommended. Tubes and their electrical connections should be constructed to prevent 
overheating o f light source. Average light intensity above working surface should be 1500 -1800 lux, as 
measured 30 cm above centre of acrylic sheet. Distribution of illumination should be in ratio of 3:1:0:1, 
i.e. brightness directly above light source should be 3 time s greater than that of outer field, and 
brightness of outer limit of visual field should be not more than 0.1 that of inner field.  Illumination in 
examining room should be low enough not to interfere with detection of parasites, but not so dim as to 
cause  excessive eye fatigue.  
 
4 Sample preparation  
 
Weigh entire sample and record weight on analytical reporting form.  
 
 
4.1 Fillets  
If fillets are large (200 g or larger), use one fillet for each of the 15 subsamples. If fillets are small (less 
than 200 g), randomly select fillets to prepare 15 subsamples of approximately 200 g each. Record 
AFRICAN STANDARD  CD-ARS 1 132-3:2023 
2 © ARSO 20 23 — All rights reserved  actual weight analysed for each subsample. If fillets are more than 30 mm thick, cut with a sharp knife 
into 2 pieces of approximately equal thickness (not to exceed 3 0 mm per fillet). Examine both pieces 
as described below.  If fillets have a thickness of 20 mm or less, examine whole.  
NOTE: Skin of fillets must be removed before examination.  
 
4.2 Fish blocks  
 
Analyse 15 subsamples randomly selected from 2 thawed and dr ained blocks. Prepare the subsamples 
as described for fillet, above. Note separately any parasites observed in minced fish added to block 
around subsamples.  
 
4.3 Steaks, loins, chunks  
 
Prepare as for fillets.  
 
4.4 Minced fish 
 
If frozen in blocks, analyse 15 subsamples randomly selected from 2 thawed and drained blocks. 
Prepare subsamples as described for fillets, above. Select portions from different parts of block. If not 
in blocks, analyse 15 -200 g portions. Do not further shred or chop minced fish.  
 
4.5 Breaded fish portions  
 
Thaw frozen products at room temperature in a beaker of appropriate size. After thawing, pour hot  
(50 °C) solution of 2 per cent sodium lauryl sulfate in water over fish in increments of 100 m l per 300 g 
of product. Stir with glass  rod for 1 min. Let stand for at least 10 min or until breading separates from 
flesh. Transfer individual portions to No. 10 sieve nested over No 40 sieve. Wash breading through No. 
10 sieve with gentle stream of warm tap water. Periodically examine No. 40  sieve containing the 
breading. Using UV light. Parasites will appear fluorescent under this light. Note any parasites detected 
and record on the analytical reporting form. Discard breading by backflushing the No. 40 sieve with tap 
water.  
 
Examine fish po rtions by candling, using white light.  If the flesh is pigmented, use UV light.  
 
4.5.1  Examination  
 
Parasites near the surface will appear red, tan, cream -coloured, or chalky white. Parasites deeper in 
the flesh will appear as shadows. Remove, representative types of parasites or other defects found. 
Record general location, size, identification, and other observations as outlined below. For minced fish, 
spread portion on light table to a depth of 20 -30 mm for examination. Select representative parasites 
for descriptive analysis.  
 
4.5.2  Ultraviolet examination of dark -fleshed fish  
 
Visually examine each portion (de -breaded or de -skinned, as necessary) on both sides under a desk 
lamp or similar light source. A magnifying desk lamp may be used. Report findings as described below. 
Conduct UV examination in darkened room. Examine each portion on both sides with reflected 
longwave UV light (366 nm wavelength). Parasites should fluoresce green under light of this 
wavelength. Fish bones and conn ective tissues, which also fluoresce blue, may be differentiated by 
their regular distribution and shape. Bone fragments will be rigid when probed.  
 
CAUTION ! Never expose unprotected eyes to UV light from any source either direct or reflected.  
Always wear  appropriate eye protection such as goggles with uranium oxide lenses, welder’s goggles 
etc. when such radiations are present and unshielded. Keep skin exposure to UV radiations to a 
minimum.  
 
 
ENCYSTED PARASITE IN THE MUSCLE OF FISH  CD-ARS 1 132-3:2023 
© ARSO 20 23 — All rights reserved  3  
Figure 1 A  
 
 
A. Prohemistominae metacercariae  
 
B. Heterophidae metacercariae  
 
C. Clinostomum sp. metacercariae  
 
 
 
 
 
  
 
 
 
 
CD-ARS 1 132-3:2023 
4 © ARSO 20 23 — All rights reserved   
Figure 1B  
 
A Digenea gen. sp metercariae  -1- 
 
B Digenea gen. sp metercariae  -2- 
 
C Digenea gen. sp metercariae  -3- 
 
D Digenea gen. sp metercariae  -4- 
 
 
 
 
 
 
 
 
 
 
 
  
CD-ARS 1 132-3:2023 
© ARSO 20 23 — All rights reserved  5 Bibliography  
 
 
Working Group to identify and acknowledge useful literature used in the preparation of this standard.  
 
 
 CD-ARS 1 132-3:2023 
© ARSO 20 23 — All rights reserved