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Development and use of a pepsin digestion method for analysis of shellfish for Cryptosporidium oocysts and Giardia cysts.
J Food Prot. 2008 May; 71(5):959-66.JF

Abstract

Investigation of shellfish for Cryptosporidium oocysts and Giardia cysts is of public health interest because shellfish may concentrate these pathogens in their bodies, and because shellfish are frequently eaten raw or lightly cooked. To date, the methods used for the analysis of shellfish for these parasites are based on those originally designed for water concentrates or fecal samples; the reported recovery efficiencies are frequently relatively low and the amount of sample examined is small. Here, we describe the development and use of a pepsin digestion method for analyzing shellfish samples for these parasites. The conditions of the isolation method did not affect subsequent parasite detection by immunofluorescent antibody test, and allowed examination of 3-g samples of shellfish homogenate, with recovery efficiencies from blue mussel homogenates of between 70 and 80%, and similar recoveries from horse mussel and oyster homogenates. Although exposure of the parasites to the conditions used in the technique affected their viability, as assessed by vital dyes, the maximum reduction in viability after 1-h incubation in digestion solution was 20%. In a preliminary survey of shellfish collected from the Norwegian coast, Cryptosporidium oocysts were detected in blue mussel homogenates in 6 (43%) of 14 batches and Giardia cysts in 7 (50%) of these batches. However, this relatively high occurrence, compared with other surveys, may be due to the higher recovery efficiency of the new method, and the relatively large sample size analyzed. A more comprehensive study of the occurrence of these parasites in shellfish would be of pertinence to the Norwegian shellfish industry.

Authors+Show Affiliations

Parasitology Laboratory, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, 0033 Oslo, Norway. lucy.robertson@veths.noNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

18522030

Citation

Robertson, L J., and B Gjerde. "Development and Use of a Pepsin Digestion Method for Analysis of Shellfish for Cryptosporidium Oocysts and Giardia Cysts." Journal of Food Protection, vol. 71, no. 5, 2008, pp. 959-66.
Robertson LJ, Gjerde B. Development and use of a pepsin digestion method for analysis of shellfish for Cryptosporidium oocysts and Giardia cysts. J Food Prot. 2008;71(5):959-66.
Robertson, L. J., & Gjerde, B. (2008). Development and use of a pepsin digestion method for analysis of shellfish for Cryptosporidium oocysts and Giardia cysts. Journal of Food Protection, 71(5), 959-66.
Robertson LJ, Gjerde B. Development and Use of a Pepsin Digestion Method for Analysis of Shellfish for Cryptosporidium Oocysts and Giardia Cysts. J Food Prot. 2008;71(5):959-66. PubMed PMID: 18522030.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Development and use of a pepsin digestion method for analysis of shellfish for Cryptosporidium oocysts and Giardia cysts. AU - Robertson,L J, AU - Gjerde,B, PY - 2008/6/5/pubmed PY - 2008/7/9/medline PY - 2008/6/5/entrez SP - 959 EP - 66 JF - Journal of food protection JO - J Food Prot VL - 71 IS - 5 N2 - Investigation of shellfish for Cryptosporidium oocysts and Giardia cysts is of public health interest because shellfish may concentrate these pathogens in their bodies, and because shellfish are frequently eaten raw or lightly cooked. To date, the methods used for the analysis of shellfish for these parasites are based on those originally designed for water concentrates or fecal samples; the reported recovery efficiencies are frequently relatively low and the amount of sample examined is small. Here, we describe the development and use of a pepsin digestion method for analyzing shellfish samples for these parasites. The conditions of the isolation method did not affect subsequent parasite detection by immunofluorescent antibody test, and allowed examination of 3-g samples of shellfish homogenate, with recovery efficiencies from blue mussel homogenates of between 70 and 80%, and similar recoveries from horse mussel and oyster homogenates. Although exposure of the parasites to the conditions used in the technique affected their viability, as assessed by vital dyes, the maximum reduction in viability after 1-h incubation in digestion solution was 20%. In a preliminary survey of shellfish collected from the Norwegian coast, Cryptosporidium oocysts were detected in blue mussel homogenates in 6 (43%) of 14 batches and Giardia cysts in 7 (50%) of these batches. However, this relatively high occurrence, compared with other surveys, may be due to the higher recovery efficiency of the new method, and the relatively large sample size analyzed. A more comprehensive study of the occurrence of these parasites in shellfish would be of pertinence to the Norwegian shellfish industry. SN - 0362-028X UR - https://www.unboundmedicine.com/medline/citation/18522030/Development_and_use_of_a_pepsin_digestion_method_for_analysis_of_shellfish_for_Cryptosporidium_oocysts_and_Giardia_cysts_ DB - PRIME DP - Unbound Medicine ER -