Anisakid Parasites in Commercial Hake Ceviche in Southern Chile

摘要

The objective of this research was to determine the occurrence of anisakid nematode larvae in hake ceviche sold in restaurants in Valdivia (39°48′S, 73°14′W) and Niebla (39°49′S, 73°22′W), Chile. Between August and November 2012, 78 portions of ceviche were collected (6 from each of the 13 restaurants that sell this product). Each portion was weighed and divided into approximately 30-g samples, which were placed in petri dishes with 0.15 M NaCl. All samples were manually shredded and then examined with a stereomicroscope. Muscles of 41 southern hake (Merluccius australis), a fish sold fresh in Valdivia, also were examined by candling to determine the presence of anisakid larvae. The presence of Pseudoterranova larvae in ceviche sold in Chile was identified for the first time. The pH of ceviche ranges from 4.1 to 4.8, which favors the presence of viable anisakid larvae that tolerate the acid pH similar to that found in the stomach of their mammalian host. No significant differences (P ＞ 0.05) in the prevalence, mean abundance, and mean density of anisakid larvae in ceviche were found between localities. Larvae were detected in ceviche from 3 of 6 restaurants in Valdivia and 4 of 7 restaurants in Niebla. Of the 78 examined portions of ceviche, 21.8% had larvae. The prevalence of viable larvae was 16.7 and 7.1% in the examined portions from Valdivia and Niebla, respectively. In the 41 hake muscle samples from Valdivia, the prevalence (4.9%), mean abundance (0.1), and mean density (0.03) was the same for Pseudoterranova and Anisakis larvae. No inspection processes or pretreatments are currently in place for raw fish to achieve safe conditions for ceviche in restaurants from Valdivia and Niebla.