Photo: Efra Figueroa
#2
Selecting Seafood
Seafood intended for human consumption must be appropriately handled and refrigerated as soon as possible, otherwise, they quickly begin spoiling and degrading. Eating spoiled food can be hazardous to human health. Therefore, obtaining food of the highest quality and freshness can make a huge difference not just in a person’s health, but in the enjoyment of said food. This document provides a series of observations you may use when purchasing fish and shellfish, whether they are frozen, fresh or alive. The characteristics mentioned in this document may vary from one organism to the other; nonetheless, the suggestions may still provide help when selecting products. Make sure you visually inspect the product and check the expiry date when available (particularly in imported or frozen goods) before purchasing anything. Similarly, check the meat’s firmness and that the smell is pleasant. We recommend knowing local fishing regulations as they pertain to fish and shellfish sales, since these establish fishery management for
marine species. During fishing closures, certain species are forbidden from being caught, sold, bought and distributed. Fishing closures usually exist as a protected period in which species breed and/or lay eggs to procreate the next generation. These reproductive processes ensure a population that will continue to exist in the future. Therefore, obeying these regulations is vital to preserve ecologic and economic longterm benefits so that fishers can have healthy fish and shellfish populations to ensure their future livelihoods. It also guarantees local fish and
Careful! Some fish, especially those caught in lakes and streams (although by no means restricted to just these bodies of water) may contain dangerous levels of polychlorinated biphenyls (PCBs). These pollutants accumulate in fish fatty tissues and can cause health complications in people. However, the risk is diminished when removing a fish’s skin and fat prior to preparation and consumption.
Iced or refrigerated products Whole fish The fish you purchase should be refrigerated and placed on a thick layer of ice while it is on display. Furthermore, it is preferable that the fish be covered. The product should also have a pleasant, fresh smell like ocean water. Fish that is not very fresh will smell unpleasant, sour or like ammonia. The eyes should be bright and clear, and they should be whole and slightly bulging and not sunken. If the gills have not been removed, the consumer should check that they still look fresh (red or bright pink) and not oozing any milky or slimy discharge. If the fish has not been scaled, the scales should be firmly attached to the skin. Finally, the meat should be firm, slightly elastic and glossy.
Choosing fresh fish is important when avoiding health complications. High temperatures endured during transport (poorly refrigerated fish) and exposure to direct sunlight foster toxin development in some fish species. These compounds are naturally formed by bacteria and are known as scombrotoxins (histamines). Consuming products with high levels of these toxins can result in illnesses to the gastrointestinal (digestive), cutaneous (skin) and neurological (nerves) systems.
Fish fillets Top-quality fish fillets should be bright and colorful. The meat should never look opaque, discolored and/or pale, since this would indicate that the fillet is old. Another spoilage indicator would be fillets that look brownish, yellowish or greenish. Besides, you should check that fillets are not dried out or too soft; these, along with the rest of the fillet, should be firm and glossy. Crustaceans The crustaceans you want to buy should be brightly-colored and the meat should be firm. If they are pre-cooked, they should look pink. If the meat is raw, on the other hand, the meat should be white or translucent. Crustaceans shouldn’t have too strong of a smell, but if they do, it should be a fresh scent. These organisms should have their heads firmly attached to their bodies, if sold whole. The carapaces shouldn’t have any abnormal black spots or borders. However, it is important to know some of these species, since there are several which do naturally feature 2
Dato Marino #2 / Sea Grant Puerto Rico / 2018
Photo: Efra Figueroa
List of useful observations when selecting and purchasing seafood
Why is freshness important?
Photo: Efra Figueroa
seafood availability. It is worth mentioning that every fisher should know about fishing closures and areas in which fishing is allowed.
Squid Fresh squid should be firm. The eyes should be whole and have a bright appearance. A squid with wrinkled, torn skin is not fresh, and shouldn’t be purchased. On the outside, squid should be cream-colored, with spots that range from brown to red. As the squid grows older, the skin turns pink and the meat becomes yellowish.
Recommendations when buying fresh products Determine the fish’s freshness by checking the elasticity of the meat. Press down on the meat with a fingertip and lift your finger. If the meat quickly returns to its natural shape, it is fresh. If, on the other hand, the indentation remains, then the meat is not very fresh.
Live Products Clams, oysters and mussels The consumer must check that the shells are complete. An organism with a cracked or broken shell shouldn’t be purchased. The interior should be creamy-colored and either have a pleasant smell or no smell at all. The liquid around the flesh should be clear. Bivalves tend to have a small opening between the shells, which moves when the organism is alive. These animals should never be bought if they have already died. These, as well as others, quickly decompose and become toxic.
Photo: Efra Figueroa
Scallops Just like the crustaceans, scallops should be firm and have a pleasant, fresh smell. At no moment should a fresh scallop ever smell sour or like iodine. Small scallops come in a variety of colors – creamy, white, pink or light orange. Bigger, deep-water scallops have very similar colors to the smallest ones.
Photo: Efra Figueroa
black striations or dark colors in their carapaces. Therefore, spots and dark color streaks don’t necessarily indicate spoilage; it is just something to keep in mind.
Recommendations when choosing live oysters, clams and mussels Do the “knock test”. Lightly tap them on the shell. If the organism closes its shell, it is alive and therefore fresh. If it doesn’t close, or if it has always remained closed, don’t take it, since this might mean that the organism is deceased. Dato Marino #2 / Sea Grant Puerto Rico / 2018
Photo: Efra Figueroa
It is very important to know, as a consumer, where bivalves were harvested. Bivalves are filter-feeders,
3
Photo: Efra Figueroa
so they can accumulate pollutants from their surrounding environment. You must take care to not buy bivalves that were harvested in waters contaminated with Escherichia coli (E. coli), a fecal coliform. E. coli levels are high in areas in which raw sewage is discharged into the sea. As a consumer, you must be vigilant about this, and be careful and selective when purchasing.
Photo: Efra Figueroa
Lobsters and crabs If lobsters and crabs are sold fresh, they should be alive. This is because, left unfrozen, dead crustaceans decompose very quickly. You can determine freshness by judging movement – if the animal moves its legs, it is alive and therefore, fresh.
Choose products that are in completely sealed packages that aren’t broken, torn or crushed at the edges. Similarly, observe that the products are frozen solid inside the package. The package interior should be free of frost and ice crystals, since these indicate that the product has been frozen for a long time or that the product has been Recommendation when buying frozen products Avoid selecting and purchasing seafood above the “frost line” or “freezer line”; that is to say, on the freezer limit at the top of the freezer. Products found here often have frost crystals clustered on the package, and the product may be freezer-burned. These conditions dehydrate the product and alter its taste. However, they are safe to eat. 4
Escherichia coli (E. coli) is a pathogenic bacterium. It has been known to cause urinary tract infections, diarrhea, pneumonia, and other illnesses. This type of bacteria usually inhabits the intestinal tract in humans and animals.
Dato Marino #2 / Sea Grant Puerto Rico / 2018
Illustration: Deifchiramary Tirado Choque
Photo: Efra Figueroa
Frozen products Fish and shellfish Seafood sold from a freezer should retain its natural color. The exterior should preferably be glossy. However, gloss is often diminished because freezing dehydrates the products. Nevertheless, opaque skin isn’t a definite indicator of lack of freshness. Discolorations, white spots of blackened areas, on the other hand, are to be avoided.
Foto: Gerick Bergsma 2011/Marine Photobank
thawed and refrozen sometime previously. There must be no frozen liquid inside the package. Fish fillets Frozen fish fillets should be firm and have cleancut edges. Shrimp The shell on the shrimps, whenever sold as a frozen product, should be colorful. Depending on the species, they can be grayish green, orange-pink or pale pink. Always follow the closure limits, whether you are a consumer or a fisher. This information is crucial from the ecological and commercial standpoints. Please take into consideration the information and suggestions provided here. The results will be the procuring of safe products that guarantee best quality and enjoyment.
If you wish to obtain more information about courses and workshops related to the resources and topics presented in this Ocean Fact, go to Facebook and ‘Like’ the Agricultural Extension Service in Moca’s Facebook page. The Agricultural Extension Service in Moca is part of the UPR-Mayagüez College of Agricultural Sciences.
Glossary Ammonia - colorless, gaseous chemical with an irritating smell, sometimes perceived in salts and some cleaning products. Pathogenic - something which causes disease.
Dato Marino #2 / Sea Grant Puerto Rico / 2018
5
References Administración de Drogas y Alimentos de los Estados Unidos: Centro para la Seguridad Alimentaria y la Nutrición Aplicada. (2006). Pescados y mariscos frescos y congelados: Cómo seleccionarlos y servirlos de forma segura. Retrieved from http://www.multivu.com/players/Spanish/7594351-fda-seafood-safety/ Anderson, K. J., Whitlock, J. E., Harwood, V. J. (2005). Persistence and Differential Survival of Fecal Indicator Bacteria in Subtropical Waters and Sediments. Applied and Environmental Microbiology, 71(6), 3041-3048. Retrieved from http://aem.asm.org/content/71/6/3041.short Briones, A. Toxinas naturales de origen animal: Mitilotoxinas, Ictiotoxinas. Universidad Autónoma de Madrid, Departamento de Farmacología: Toxicología Alimentaria. Retrieved from https://www.uam. es/departamentos/medicina/farmacologia/especifica/ToxAlim/ToxAlim_L11d.pdf Corrales Venegas, M. (2015). Acumulación de metales pesados en bivalvos y sus efectos tóxicos en la salud humana: Perspectivas para el estudio en Costa Rica. Revista Pensamiento Actual, 15(25), 173-181. Department of Health and Human Services: Public Health Service. (2004). Public Health Statement: Ammonia. Agency for Toxic Substances and Disease Registry. Retrieved from https://www.atsdr.cdc. gov/toxprofiles/tp126-c1-b.pdf National Oceanic and Atmospheric Administration: NOAA Fisheries: FishWatch. (2017). Buying and Handling. FishWatch: U.S. Seafood Facts. Retrieved from https://bit.ly/2H13o7e Programa de Colegio Sea Grant: Universidad de Puerto Rico. Datos Marinos: ¿Cómo sabemos que el pescado o marisco que estamos comprando está verdaderamente fresco? Real Academia Española. (2017). Amoniaco [Def. 1]. In Diccionario de la Lengua Española. Retrieved from http://dle.rae.es/?id=2OlqumF Real Academia Española. (2014). Inodoro [Def. 1]. In Diccionario de la Lengua Española. Retrieved from http://dle.rae.es/?id=Lhhw2Qa Real Academia Española. (2014). Patogenia [Def. 1]. In Diccionario de la Lengua Española. Retrieved from http://dle.rae.es/?id=SAWhSWg The Library of Congress. (2017). What is “Freezer Burn?”. Everyday Mysteries. Retrieved from https:// www.loc.gov/rr/scitech/mysteries/freezerburn.html United States Department of Health & Human Services: Centers for Disease Control and Prevention. (2017). E. coli (Escherichia coli). Retrieved from https://www.cdc.gov/ecoli/index.html United States Food and Drug Administration. (2017). Fresh and Frozen Seafood: Selecting and Serving It Safely. Retrieved from https://bit.ly/2IOlSK7 Credits Revised and modified by: Wanda M. Ortiz Báez and Verónica Santiago Text edited by: Mariana González González González and Cristina Olán Martínez Content revised by: Myriam Meléndez and Michelle T. Schärer Umpierre English translation by: Wilmarie Cruz Franceschi Drafted by: Oliver Bencosme Palmer Photography by: Efra Figueroa Acknowledgements: The University of Puerto Rico Sea Grant Program would like to thank Verónica Santiago and Myriam Meléndez, both from the Agricultural Extension Service, for their help in preparing this Ocean Fact. Published on: June 2018 UPRSG-G-292
6
Dato Marino #2 / Sea Grant Puerto Rico / 2018