Browsing by Author "De-Los-Santos, Estrellita Rojas"

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Influence of Fat Content on the Salt-Ripening Process of the Peruvian Anchovy (Engraulis ringens)
(Asian Fisheries Society, 2025-6-30) Valverde-Vera, Verónica; De-Los-Santos, Estrellita Rojas; Mondragón-Martínez, Aarón; Vela, Jessica; Olivares, Fabiola; Albrecht-Ruiz, Miguel
The study evaluated the influence of fat content on the salting ripening process of Peruvian anchovy (Engraulis ringens) at an industrial scale. Two batches of two tonnes each of E.ringens were processed, with heads and viscera removed before placing the fish in barrels with salt for ripening. The first batch contained 9.0 % fat, and the second 6.8 %. Sensory qualities were evaluated and the documented ripening times revealed no significant differences between batches; however, the higher-fat batch exhibited a slower decrease in water activity (aw) and reached sensory ripe slightly later than the batch with lower fat content. Physico-chemical analyses within each batch showed average increases in the proteolysis index (PI), total volatile basic nitrogen (TVB-N), and trimethylamine (TMA), but no significant differences between batches. The high variability inherent to industrial-scale processing limited the establishment of a direct correlation with fat content. Regarding amino acid composition, the initial histidine content in raw fillets was 2.1 g.100 g-1, representing 81 % of free amino acids; however, during salting, most histidine diffused into the brine, leaving only 0.3 g.100 g-1 in the ripened product. Ripening led to an increase in free amino acids, particularly leucine, lysine, and glutamic acid, while the total amino acid content in the muscle decreased due to osmotic processes, salt-induced protein solubilisation, and proteolytic activity. Histamine levels in both batches remained below 50 mg.kg-1 at the end of ripening, complying with food safety standards.
Molecular and morphological identification of Adenocephalus pacificus (Cestoda) isolated from South American sea lion Otaria byronia stranded on the northern Peruvian coasts
(Polish Parasitological Society, 2021) Mondragón-Martiínez, Aarón; Martínez-Rojas, Rosa; Cruz-Neyra, Lidia; De-Los-Santos, Estrellita Rojas; Delgado-Candela, Abraham
The most frequent etiologic agent of diphyllobothriosis in South America and the only one confirmed by molecular data in human cases in Peru is Adenocephalus pacificus (syn. Diphyllobothrium pacificum). This cestode is transmitted by ingestion of the plerocercoids found in marine fish, causing a parasitic zoonosis. The objective of the present study was to identify two cestodes isolated from two specimens of the South American sea lion (Otaria byronia) stranded on the beaches of Huacho and Barranca cities, located on the northern Peruvian coasts, in the department of Lima. Tapeworms were confirmed by morphological characteristics due to the presence of transverse papilla-like tegumental protuberances in proglottids and small sized eggs, as well as by sequencing of the partial cytochrome c oxidase subunit 1 (mtDNA-COI) gene that are congruent with additional available A. pacificus sequences. Even though sea lions in Peru are distributed along the coast and in areas of difficult access, generally located in protected natural areas, the fortuitous finding represented an opportunity to confirm the presence of A. pacificus in South American sea lions. This report of tapeworm A. pacificus could allow future monitoring of the occurrence and geographical distribution of this causative agent in epidemiological studies, since it is one of the main species of zoonotic importance in Peru. © 2024 Elsevier B.V., All rights reserved.
Molecular identification and epidemiological data of Anisakis spp. (Nematoda: Anisakidae) larvae from Southeastern Pacific Ocean off Peru
(Elsevier BV, 2021-12) Martínez-Rojas, Rosa; Mondragón-Martínez, Aarón; De-Los-Santos, Estrellita Rojas; Cruz-Neyra, Lidia; García-Candela, Enrique; Delgado-Escalante, Abraham; Sanchez-Venegas, J.R.
The objective of this study is to determine the infection status of nematode larvae and record epidemiological molecular data in commercial fish from the southeast Pacific off the central coast of Peru. Anisakiasis is a fish-borne zoonosis caused by Anisakis larvae, parasites of relevance in the fishery resources that have negative impact on public health. Between January 2012 to December 2014, 345 specimens of four fish species (Trachurus symmetricus murphyi, Scomber japonicus peruanus, Merluccius gayi peruanus and Seriolella violacea) were examined for Anisakis sp. larvae. A total of 997 Anisakis sp. larvae were found in the body cavity of 196 fish (total prevalence 53.7%, total mean intensity 5.08). After morphological analysis, 958 (96.08%) larvae were identified as Type I and 39 (3.92%) as Type II. Specimens were identified by molecular analysis of the mitochondrial cytochrome c oxidase subunit II (cox2) gene, confirming that A. pegreffii is the predominant species and the most important agent of human anisakiasis off the Peru Central Coast. In addition, we revealed the occurrence of A. physeteris (s.l.) in S. japonicus peruanus (P = 18.0%; MI = 2.17). Therefore, the results obtained in the present study improve the knowledge of the occurrence of Anisakis species in the commercial fish from the Southeastern Pacific Ocean, highlighting the importance of considering a potential hazard for humans and the necessity of further research in other fishes of greater preference by the Peruvian population. © 2021 Elsevier B.V., All rights reserved.