In the past few decades, there has been a growing demand for fish (wild-caught and aquaculture), especially in developing countries, due to increased knowledge of their health benefits, urbanization and rising incomes. In 2016, the world’s per capita consumption was about 20.3 kg (compared to 10 kg in 1960s) annually. Fish are an important source of animal protein and provide nutrients to more than 2.6 billion people in developing countries. Fish provide about 20-50 percent of the average per capita animal protein intake for people in some developed countries. Fish are excellent sources of high-quality protein, long-chain omega-3 polyunsaturated fatty acids, essential minerals (e.g., calcium, iodine, iron, phosphorus, selenium, zinc), and vitamins (e.g., A, B, D). These elements/components are very important in the first 1,000 days of a child’s life. They are also important in reducing the risks of non-communicable diseases.

However, fish are a highly perishable food, they can accumulate pathogens and natural toxins and can be a vehicle to potential risks and foodborne diseases. For example, fish can be contaminated with food safety hazards from sewage-contaminated waters. Fish can also be contaminated during handling, processing, or preparation from an infected food handler, or cross-contamination through contact with contaminated fish, water, or instruments. The causes of foodborne illness associated with fish fall into two major categories: biological hazards and chemical hazards. 

Fish can be contaminated with biological pathogens including bacteria (Vibrio cholerae, V. parahaemolyticus, and V. vulnificus, Salmonella species, Aeromonas species. Listeria monocytogenes, Clostridium botulinum, Staphylococcus aureus), viruses (norovirus, Hepatitis A, Norwalk-like viruses, etc.), and parasites (Anisakiasis). These biological pathogens are commonly associated with poor water quality and inadequate waste-water management, or poor siting and spatial planning. 

Fish can also be contaminated with biochemical hazards such as naturally occurring shellfish biotoxins including paralytic shellfish poisoning (PSP) toxins, neurotoxic shellfish poisoning (NSP) toxins, diarrhetic shellfish poisoning (DSP) toxins, azaspiracid shellfish poisoning (AZP) toxins, and amnesic shellfish poisoning (ASP) toxins. Wild or farmed shellfish become contaminated with these toxins by feeding on certain toxic algae in the water during algal blooms. Some countries have established systems to monitor lake and coastal waters for occurrences of toxic algal blooms in order to issue warnings and ban harvests to reduce health risks. Toxins like ciguatera and tetrodotoxin (pufferfish toxin) can be formed in certain fish that have been harvested from certain areas where fish feed on toxic algae. It is unclear however whether the fish itself produces tetrodotoxin or if it is formed in the fish by eating toxic algae. Certain fish species including scombroid fish (tuna, mackerel) and non-scombroid fishes (e.g., mahi-mahi, bluefish, amberjack, swordfish, herring, sardines, anchovies) can form histamine poisoning (scombrotoxin). Histamine is usually formed in marine fish which have undergone some degree of spoilage or unsatisfactory storage conditions by certain types of naturally-occurring bacteria. These bacteria can grow and produce histidine decarboxylase enzyme. This enzyme can convert histidine (amino acid) to histamine (a biogenic amine). Once histamine has formed, it cannot be removed or destroyed. At 32°C, unsafe levels of histamine (the histamine threshold limit is 50 PPM in the U.S.) may appear within six hours. At 21°C the toxic conditions may appear within 24 hours. Other health risks can occur when fish are exposed to heavy metals (e.g., mercury), pesticides, intentionally added chemicals (e.g., preservatives, nutritional additives, color additives), and unintentional or incidental chemical (e.g., pesticides, sanitizers, chlorine, lubricants, paints).

Figure 1: Food associated with foodborne outbreaks in the U.S. between 2009 and 2016 (CDC).

For example, fish are responsible for an important proportion of foodborne outbreaks in the United States (these outbreaks can cause serious socio-economic damage for the fish industry). According to the Centers for Disease Control and Prevention (CDC), fish and fish products were responsible for about 26 percent of all outbreaks in the U.S. between 2009 and 2016 (Figure 1). There were two outbreaks associated with oysters imported from Mexico & tuna imported from Vietnam in the U.S. in 2019, so far. 

Chemical hazards are generally heat-stable, processing including cooking methods do not destroy them, therefore monitoring [applying seafood hazard analysis critical control points HACCP, good manufacturing practices (GMPs), good aquacultural practices (GAQPs), good hygiene practices (GHPs), good handling practices (GHPs), sanitation control procedures (SCPs), etc.] of fish or shellfish is the most important measure to protect people from chemical hazards. However, biological hazards can be reduced, prevented or completely eliminated by applying specific measures (e.g., interventions, processing, technologies). See measures taken by the fish industry and consumers below. Food safety is everyone's business including governments, the seafood industry, consumers, and donors. Foodborne illnesses associated with fish can be controlled, reduced, eliminated or prevented by developing and implementing proper food safety control programs and measures.

Actions that can be taken to improve the safety and quality of fish 

Governments: 

• Source country governments should commit to the sustainable, inclusive and transparent management of their fisheries and supply chains; require the use of electronic catch documentation and traceability systems to track fish products; and increase funding for fisheries and food safety management by capturing and reinvesting economic rents from fishing.
• Governments should develop and enforce the implementation of food safety regulations and standards (such as the Codex Alimentarius Commission standards) including good handling practices, good manufacturing practices, good hygiene practices, sanitation control procedures, traceability [a record-keeping system to track the flow of food products (one step back and one step forward) in the value chain from production to sale], regulations, and the HACCP program to improve the safety of fish (reduce the risk of fish safety hazards). In the U.S., the procedures for the safe and sanitary processing and importing of fish and fishery products regulation (21 CFR 123) requires that HACCP plans are prepared for all fish and fishery products if a significant food safety hazard is identified.
• Importing country governments should require transparent catch documentation and traceability information on all imported seafood products.
• Governments should work with small-scale fishing and processing associations to increase their capacity for safer post-harvest handling and processing.
• Governments, in partnership with industry, could establish monitoring systems for toxic algal blooms and proper response protocols to warn and protect public health.

Fish Industry/Businesses:

• Establish effective producer and processor associations, which function properly to solve real problems that face small producers and processors.
• Implement food safety regulations and standards (see measures under governments). 
• Use traditional processes including drying, salting, smoking, fermenting, canning, etc.
• Use novel technologies including electrolyzed water, high hydrostatic pressure, modified atmosphere packaging, ozone, irradiation (including X-ray), heat-cool pasteurization, ultraviolet (UV) radiation, etc.
• Use antimicrobials agents including organic acids, plant-derived substances (spices, herbs, essential oils, etc.), etc.
• Use ice and cold chains in conjunction with the use of secure tenure arrangements and contractual agreements with fishing associations that set and maintain sustainable harvest control levels. Requirements for secure tenure and harvest control levels are critical to prevent overfishing.

Consumers:

• Consumers (through consumer organizations) should demand that all fish products be required to include catch documentation and traceability information.
• Consumers should look for fish products that are third party certified as being sustainably and responsibly produced and tracked along its supply chain.
• Consumers should be aware of the health risks of eating unsafe fish. Consumers must handle fish properly during buying, preparing, and storing fish.
• Establish effective consumer associations, which understand and solve real problems that face consumers.
• Follow the four steps to food safety; 1) clean (always wash hands, utensils, and surfaces, 2) separate (don’t cross contaminate), 3) cook to an internal temperature of 63° C, and 4) chill (refrigerate and freeze food properly).
• Buy only high-quality fish (for example for fresh fish, eyes should be clear and shiny, gills should be red with no odor, fish should smell fresh, not fishy or ammonia-like, body has firm flesh; flesh should spring back when pressed, etc.).
• Do not leave fish at room temperature more than 1-2 hours.
• Do not eat raw fish, especially at-risk groups including elderly, children, pregnant women, and people with weakened immune systems (HIV, cancer, diabetes, etc.). Healthy people may eat raw fish (sushi, sashimi, oysters, etc.) but the fish must be first frozen to kill parasites. However, consumers should be aware that freezing doesn't kill pathogens. 

Donors:

Donors can also play an important role of ensuring the safety of fish and fish products in developing countries by building government and industry commitment and capacity to better manage fisheries and fish products. (see below for examples of the Feed the Future fish projects in developing countries). Given the importance of wild-caught fisheries, donors should invest more in fish and food safety related projects in developing countries, aligning assistance with sustainable fishing practices. Feed the Future has been investing in several fish projects that assist in building the capacity of local governments and businesses, including:

• The Feed the Future Innovation Lab for Fish (FIL). The FIL is a five-year project (US $15 million) that aims to support the sustainable development of fish systems in developing countries (presently in Bangladesh, Nigeria, Kenya and Zambia). 
• The USAID/Senegal COMFISH Plus project empowered women in artisanal processing of fisheries products in conjunction with improving sustainable fishing practices. 
• The USAID/West Africa BaNafa project built the capacity of the TRY Oyster Women’s Association.
• The USAID/Ghana Sustainable Fisheries Management Program works with women artisanal fisheries and processors.

If actors (governments, fish industry, donors, and consumers) engage as suggested, then the safety of fish (numbers of outbreaks and illnesses associated with fish will be reduced) will be ensured, post-harvest fish losses will be reduced, and fish will be more sustainably managed. These actions will improve nutrition, food security, resilience, and the livelihoods of millions of people.