Date of Award

Fall 12-2022

Document Type


Degree Name

Master of Science (MS)


Food Science

First Advisor

Rosalee Hellberg, Ph.D.`

Second Advisor

Anuradha Prakash, Ph.D.

Third Advisor

John Miklavcic, Ph.D


Raw, ready-to-eat (RTE) seafood products have become increasingly popular globally, but they are vulnerable to species mislabeling and substitution. DNA barcoding allows for fish species identification by extracting, amplifying, and sequencing a standardized gene target. A wide variety of fish products have been studied with DNA barcoding, but notably missing are ceviche and poke, particularly in the United States. Sushi is known to be a target of mislabeling but has not been extensively studied in Orange County, CA. The objective of this study was to investigate species labeling and use of acceptable market names for sushi, poke, and ceviche sold at restaurants in Orange County, CA. A total of 105 raw, RTE seafood products were collected, including sushi (n = 35), poke (n = 35), and ceviche (n = 35). All samples were sequenced utilizing DNA barcoding or mini-barcoding. The identified species were compared against the menu names, verbal declarations by staff, and the Food and Drug Administration (FDA) Seafood List to verify whether acceptable market names were used for each product. Of the 103 samples identified with DNA barcoding, species substitution was detected at a rate of 23.3% and unacceptable market names were found in 45.6% of samples. Overall, 63.1% of samples had some form of mislabeling. Six samples had an unacceptable market name based on the menu declaration and were also determined to be targets of species substitution based on verbal declarations by restaurant staff. When the mislabeling rates were divided based on product category, ceviche had the highest overall mislabeling rate (85.3%), followed by poke (61.8%), and sushi (42.9%). Mislabeling of ceviche and poke was primarily driven by the use of unacceptable market names, while species substitution was more common in sushi dishes. These rates reveal widespread mislabeling among raw, RTE seafood products and suggest the need for outreach efforts to ensure proper labeling of fish using acceptable market names.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Available for download on Monday, September 02, 2024