Seafood freshness

Because of the global nature of the industry, uniform standards for seafood freshness are needed. The U.S. imports large quantities of shrimp from other nations. Some of these countries have advanced technology, while others are fairly primitive in operation and troublesome both with quality and health-related matters (2). Thus, quality standards may be difficult to implement on a worldwide basis. 

Currently available methods for determining seafood freshness have been reviewed (2,3,4,5). In general, sensory and microbiological quality of seafoods are the standards most often utilized for determining freshness. There are, however, several limitations with these methods such as the need for trained technicians, problems with subjectivity, or long analysis times. Consequently, several new methods have been proposed using chemical indices of freshness that attempt to overcome these difficulties. The purpose of the present paper is to first review these methods with particular emphasis on shrimp freshness determinations and, secondly, to present experimental evidence showing that impedance can be used to denote shrimp freshness. 

Cheeses, conjugated dienoic derivatives of linoleic acid, 263,267r Chelators, 57-58 Chemesthesis, sensation based on generalized membrane response, 15,16/ Chemesthetic stimulants, description, 21 Chemical analysis of seafood freshness indicators, 250... 

Fish and seafoods Fresh or frotcn boiled broiled or baked . scalded cannerf tuna or salmon oysters fresh nr canned. Smoked, preserved or pickled fish, crab, lobster, or sardines, other sahed fish or fatty fish such es herring or mockeiet. 

Armenta, S., N. M. M. Coelho, R. Roda, S. Garrigues, and M. de la Guardia. 2006. Seafood freshness determination through vapour phase Fourier transform infrared spectroscopy. Anal. Chim. Acta 580 216-222. 

Botta, J. R. 1995. Chemical methods of evaluating freshness quality. In Evaluation of Seafood Freshness Quality, ed. J. R. Botta, pp. 9-33. New York, USA VCH Publisher Inc. 

Conducting polymers have been demonstrated to be an important material for electronic nose apphcation. Demonstration of their properties has been provide in the assessment of seafood freshness, the detection of streptomyces in potable water, and the quality of ohve oils. ... 

Gonzalez-Martin A, Lewis B, Raducanu M, Kim J (2010) An array based sensor for seafood freshness assessment. Bull Korean Chem Soc 31 3084... 

Seafood. Sorbates are used to extend the shelf life of many seafood products, both fresh and processed (103,104). For smoked or dried fish, an instantaneous dip in 5 wt % potassium sorbate or a 10-minute dip in 1.0 wt % potassium sorbate prior to drying or smoking inhibits the development of yeast and mold (105,106). For fresh fish, sorbates can be incorporated at approximately 0.5 wt % into the ice, refrigerated seawater, or ice-water slush in... 

Like plants, marine and fresh water organisms vary significantly in their response to zinc. The range of concentration among species is relatively narrow, except for oysters, which tend to accumulate zinc to very high levels. The zinc content of most seafoods ranges from 3—30 ppm. Oysters contain from 100—2000 ppm. 

Seafoods, safe level, Australia Adverse effects <40 mg/kg fresh weight (FW) 14... 

In 1824, Yohei Hanaya of Edo (now called Tokyo) eliminated the fermentation process, and began serving fresh slices of seafood on (35) bases of vinegared rice. The vinegar was probably used to mimic the taste of fermented sushi. In fact, the word sushi actually refers to any vinegared rice dish, and not to the fish, as many Americans believe (the... 

Even a single HAB episode can be extremely costly. In Maryland in 1997, reported eases of human disease associated with exposure to water containing Pfiesteria piscicida cost the seafood industry alone an estimated 46 million in lost revenue (Anderson et al., 2000). Lewis (1986) found that CFP in the South Paeifie depressed both the local and export fishing industries, affected tourism, and indirectly affected human health (because people avoided eating fresh fish). 

Over the last eight years, most of the estimated cases of world-wide poisoning in humans due to the three major kinds of seafood toxins that are found in fresh and unspoiled marine organisms, namely, paralytic shellfish poison (PSP-saxitoxins/ gonyautoxins), ciguatoxin(s), and tetrodotoxin, (13-16) were caused by ciguatera (Table I). 

Advances in maintaining seafood quality are now allowing Iceland and Norway to ship fresh fish directly into the U.S. market and sell it for a premium price. U.S. producers will have to make changes in their methods in order to avoid invasion from foreign markets (12). 

In summary, from the stanc int of risks and benefits, the benefits far outweigh the risks. Tliere are many health benefits to be derived from eating fish and shellfish as long as the nutritional quality is assured. Seafood and fresh water fish, as well as shellfish, are excellent foods. They are a renewable... 

Molluscan shellfish play an important role in human nutrition and the world economy (Wild and Lehrer, 2005). Table 4.2 provides data on the worldwide production/catch of various molluscan shellfish species for 2005. The most widely available species are oyster, squid, clam, mussel, and scallop. Aquaculture has become an important contributor to the production of molluscan shellfish with the exception of the cephalopods. However, the popularity and frequency of consumption of various molluscan shellfish varies widely across various countries and cultures. Accurate information on comparative consumption patterns for molluscan shellfish in various countries does not exist. Molluscan shellfish are consumed as freshly cooked or even raw seafood items particularly in coastal communities. But mollusks also are consumed as processed foods in a variety of forms. 

Torres, Z. Bemuy, B. Zapata, G. Vivanco, M. Kahn, G. Guzman, E. Leon, R. In Irradiation to Control Vibrio Infection from Consumption of Ra-w Seafood and Fresh Produce, International Atomic Energy Agency Vienna, 2001 37 pp. 

Sensory. Sensory analysis is one of the oldest accepted methods forjudging seafood quality and freshness. Although fairly accurate, it unfortunately requires trained, experienced panelists to attain accuracy. Perez-Villarreal (( u evaluators experienced in sensory analysis of fish to judge freshness and quality. Results of the study showed sensory scores were better correlated with microbiological analyses, especially total viable counts, than with chemical analyses such as trimethylamine or enine nucleotide decomposition (6). 

Another chemical method for measuring freshness, that is more rapid, continuous, and less destructive than other methods is the detection of volatile trimethylamine (TMA), dimethylamine (DMA), monomethylamine (MMA), and ammonia 14,15). Trimethylamine oxide (TMAO) is a decomposition product of proteins as well as present in excretions of fish 16). Spoilage bacteria can reduce TMAO to TMA plus small amounts of DMA, MMA, and ammonia. Tissue TMA levels have be correlated with the pungent odor associated with spoiled seafood as well as total bacterial counts 14). Researchers incorporated a test strip... 

When appraising these techniques for freshness determination, there is clear evidence that sdAough many of the methods are accurate, they frequently require uncooked grossly spoiled products and trained personnel for valid results. Another inconvenience is the inability to perform these tests outside of a laboratory setting. Many of the analyses take 1-2 d to obtain results. The seafood industry would benefit from a method that was rapid, sensitive during early stages of spoilage, simple to perform, and useful with both raw and cooked products. 

Boyle JL, Lindsay RC, Stuiber DA (1992) Bromophenol Distribution in Salmon and Selected Seafoods of Fresh- and Saltwater Origin. JFood Sci 57 918... 

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