Extraintestinal acanthocephalans in skipjack tuna from Mati City, Philippines: Implications for food safety and quality risks

Skipjack tuna (Katsuwonus pelamis), a major export of the Philippines, comprising over 70% of the canned tuna production, faces food safety risks from acanthocephalan parasites contaminating its muscle tissues. This study evaluated the prevalence and quality risks of skipjack tuna (n=96) from Mati City using gross inspection, pepsin digestion, microscopy, and Site, Assurance, Density, and cdEpidemiology (SADE) assessment. Intestinal infections occurred in 55.21% of fish (mean abundance 1.67, mean intensity 3.02), while extraintestinal muscle infections affected 54.17% (mean abundance 0.83, mean intensity 1.54), the first such report of muscle localization in Philippine tuna. SADE scoring showed parasites present in hypaxial and/or epaxial musculature in 52.09% of samples (S0-S2) and absent in 47.92% (S3), with all fish classified as A2 (100%: no visible lesions or tissue damage), predominantly light or very light density (D1: 60.42%; D2: 32.29%), and mainly non-zoonotic status (E3: 78.13%). Overall, the risk was classified as negligible for human health but high for detection failure, sensory defects, product downgrading, and potential non-compliance with the Bureau of Fisheries and Aquatic Resources (BFAR), Hazard Analysis and Critical Control Points (HACCP), and Codex visual inspection standards. These findings highlight the need for enhanced inspection, risk-based monitoring, and surveillance of both intestinal and extraintestinal infections to ensure the safety, quality, and export viability of tuna.