Safety and quality of water used in fish production and processing

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By Milthon Lujan

Safety and quality of water used in the production and processing of fish and fishery products – Meeting report
Safety and quality of water used in the production and processing of fish and fishery products – Meeting report

FAO and WHO published a report on the safety and quality of water used in the production and processing of fish and fishery products. It is a summary:

Background and Objectives

In 2020, the 43rd Session of the Codex Alimentarius Commission approved the “Development of Guidelines for the Safe Use and Reuse of Water in Food Production” proposed at the 51st Session of the Codex Committee on Food Hygiene (FAO and WHO, 2020a). To support this work, JEMRA was asked to provide scientific advice on sector-specific applications and case studies for determining appropriate and fit-for-purpose microbiological criteria for water sourcing, use and reuse in:

• fresh produce;
• fish and fishery products from primary production to retail; and
• the dairy sector from milk harvest to manufacturing.

The purpose of this meeting was to develop clear and practical guidance on the criteria and parameters that can be used to determine if water is fit-for-purpose for sourcing, use and reuse by applying risk-based approaches in the fisheries and aquaculture sector. The scope includes the harvesting and production of fish and fishery products across the food chain, from primary production to processing, including fishing vessels, freshwater production sites and processing facilities.

Situation analysis concerning water use and reuse in the production and processing of fish and fishery products

Water is a key element in the production and processing of fishery products. Water can be sourced from the sea, estuaries, deltas and lagoons, or, in the case of land-based fish farming systems, from springs, wells, rivers, lakes, surface runoff, groundwater or municipal sources. These waters are subject to many detrimental
effects from climate change, pollution associated with population growth and development, and increasing demands for food production and other uses. In the fish and shellfish production and processing industry, water is used:

• for rearing or harvest;
• as an ingredient;
• to transport/convey products;
• to wash, cool down and cook food;
• to clean and sanitize facilities, utensils, containers and equipment; and
• to make ice and glazed products.

There is a need to implement more sustainable practices for the management and efficient use/reuse of water resources in the fish production process, as well as a need to preserve and protect aquatic ecosystems. Any source of water can be used in primary production of fish and other aquatic organisms, provided that the risks are previously assessed, water quality is monitored, and the water complies with quality criteria defined by a risk assessment. The experts agreed that there are multiple opportunities for reusing water in the fish and fishery sector, especially in processing activities, many of which have not yet been materialized by the industry. While there are commercially available water treatment technologies to achieve the desired safety and quality attributes for specific applications, economic and environmental impact assessments are needed to facilitate decision-making by fish processors. The application for which water is intended to be reused determines whether that water is fit-for-purpose and/or a specific treatment is required before it can be used.

Fish and fishery products are generally regarded as safe, healthy, and nutritious foods. However, these products have been associated with infections and intoxications mediated by viruses (principally norovirus and Hepatitis A), bacteria (principally Vibrio spp. and Salmonella spp.), protozoans (principally Giardia sp. and Cryptosporidium sp.), and helminths (principally Anisakis spp.). In addition, intoxication by histamine associated with scombroid fish has frequently been reported. The causes of such seafood safety concerns are diverse, ranging from indigenously present microorganisms and parasites to contamination of primary production environments or poor hygiene practices during processing and consumption.

The global burden of illnesses associated with fish and fishery products is uncertain although it is thought to be substantial. It is evident from epidemiological data that water (including direct contact, indirect contact, and unintended contact) is a very important vehicle for attribution purposes, often acting as a vector to transmit pathogens among food items, thus increasing the number of people exposed to the pathogens. Depending on the pathogen, they can remain infectious in sources of water for a considerable period of time and affect the suitability of a site to produce or harvest fishery products. Populations, communities, fish producers and processors served by inadequate levels of water treatment are potentially more vulnerable to the microbiological hazards relevant to seafood products.

To mitigate these health risks, the use of water in the production and processing of fishery products should be subject to a risk-based approach covering the whole water system from the source or catchment area to storage, distribution and up to the point of use (from “source to tap”). In this context, sanitary surveys/profiling and a hazard analysis and critical control point (HACCP)-based approach such as water safety plans (WSPs) are important to determine water fitness and the likelihood of contamination in the production and processing systems. To prevent contamination, good hygiene practices should be applied to all steps of the chain, from harvesting, processing, storage and distribution. The requirements for hygienic practices constitute the prerequisite programmes that are essential for any food operation prior to the implementation of HACCP systems.

It was noted that, in many parts of the world, existing regulations limit the use of fit-for-purpose water and may not reflect current technological capabilities of water treatment. Additionally, many regulations do not sufficiently consider the widespread use of brackish water and seawater in the fisheries and aquaculture
sector. Development of new regulations and/or improvement of existing ones on quality and safety criteria for water sources, as well as minimum requirements for use in fish production and processing would assist the definition of fit-for-purpose water from different water sources and reuse applications.

Analysis of case studies for different risk-based water use and reuse processing scenarios and species

The experts were asked to appraise international case studies representing a range of risk-based water use and reuse scenarios and fish and shellfish species. From the selected case studies, the experts noted the following:

• In aquaculture, selecting a source of continuous high-quality water is critical to any successful farm operation as the source determines the quality of production water. Fish require large quantities of unpolluted water to grow rapidly and maintain their wellbeing.

• While integrated aquaculture-treated wastewater systems are becoming more common in geographies with limited access to public and municipal sources or private wells, presently there is insufficient evidence to consider the use of treated municipal wastewater as a suitable source of safe water for fish farming.

• To preserve the sanitary quality of fish and fishery products on board vessels and in processing factories, precautionary measures must be applied to control any cross-contamination and temperature abuse occurring from capture to market.

• The canning industry uses large volumes of water in multiple processing steps (e.g. cleaning, washing, cooling, thawing, ice production and removal). Each of these steps should comply with internationally recommended standards to control physical, chemical and biological hazards that could affect the safety and quality of the products.

Water quality monitoring and the use of non-culture based microbiological methods

Water monitoring is a core element of food safety management systems and is required to ensure water quality and safety and to define fit-for-purpose water in the seafood sector (FAO and WHO, 2020b). Worldwide, most seafood industries monitor the quality of the water used in production and processing of fish and understand the concept of water fitness, but monitoring practices are not always incorporated into a safety management system. Ideally, such safety management systems should be risk-based and consider historical data and expertise of the safety manager. While much good practice guidance on monitoring has been elaborated for primary production environments, there is no agreed definition of what constitutes an appropriate monitoring programme for direct and indirect contact waters in the fish processing environments.

Indicator species (e.g. E. coli) have been used in monitoring programmes to indicate the presence of pathogens for assessing the microbiological fitness of water used in fish production and processing. The use of indicator microorganisms (process indicators, faecal indicators, index organisms) has been successful in assessing the fitness of water for its intended use(s) and in reducing human exposure to microbiological hazards. However, irrespective of the fish production and processing step, today we recognize that on a sample-by-sample basis, there is rarely a direct correlation between coliform bacteria and indigenous marine pathogenic bacteria such as vibrios, enteric protozoans or viruses.

Physical or chemical parameters provide more timely results on which to base ongoing monitoring than microbiological indicator species provide and can indicate the need to take corrective action. Given that the microflora relevant for the reuse of water is operation-specific, it is generally not appropriate to rely solely on testing of microbiological parameters when these are not relevant in the context of a particular fish processing operation. It is more appropriate to conduct an operation-specific assessment to determine which indicator(s) could be used to control the reconditioning treatment for water reuse or the need to take corrective action. Since water disinfection, in particular chlorination, is commonly used to ensure water safety in fish processing plants, frequent monitoring of this stage, or on-line measurement of the disinfectant residual, is recommended.

The experts also noted that despite significant developments in non-culture-based microbiological methods (polymerase chain reaction, whole genome sequencing, microbiome analysis) for detection and quantification of pathogens in water, there is currently insufficient information on method performance, harmonization and standardization to enable their use in regulatory monitoring.

Recommendations concerning the safety and quality of water used in fish production and processing

Water use and reuse needs to be tailored to the particular conditions of the specific fish production or processing operation it is applied to, considering the operation’s potential reusable water sources, the various applications of the reused water, available recovery and treatment technologies, and the capabilities of the operator.

Frequently, relevant information on source water quality can be obtained from water suppliers. For each possible water reuse scenario considered for implementation, it is recommended that operators consider the following in assessing and managing microorganisms in water use and reuse:

• Ensure the safety of water used in the production and processing of fishery products using a risk-based approach covering the whole water system from the source to the point of use. Additionally, characterization of surface or groundwater quality in abstraction points should be extended upstream, to include the whole water catchment area.

• Coastal sources, used for abstraction of seawater in land-based establishments, cannot be guaranteed to be free from pathogens from the marine biota or from faecal contamination, and cannot be classified as fit-for-purpose sources. Seawater from offshore sources are generally considered safe. However, depending on the geographical region and temperature, seawater can hold indigenous potentially pathogenic bacteria, such as Vibrio spp., that may require control.

• Elaborate and put in place risk assessment and management procedures and implement efficient monitoring plans according to recognized guidelines or standards. The risk management is validated by both compliance with official control limits and standards in water or finished products and additional self-controls of production and processing steps.

• In the risk assessment, consider the specific waterborne hazards (e.g. marine microbiological contaminants) that may impact the safety and quality of the fishery product(s). Where necessary, develop and apply a risk-based approach such as a water safety plan (WSP).

• Where disinfection forms part of the water treatment, validate the efficacy of the disinfection step. The same applies to any other water treatment that may be applied to the water used in the industry.

• Hazards and hazardous events at the level of the catchment area were found to determine water fitness for different sources of surface and groundwater. Operators should assess all possible contamination risks from the immediate area of the catchment and seasonal and climatic factors affecting source water quality through regular testing and development of farm-specific profiling and precautionary measures. Take every precaution to protect the source water from any contamination. In some regions, this can be particularly relevant during the rainy season.

• Implement operational monitoring of the water used in the production and processing of fishery products to provide insight into process performance and associated water quality issues, enabling rapid remedial action in the event of nonconformity.

• Control the microbiological stability of finished products to confirm that food safety criteria are respected before marketing.

• Implement good hygiene practices throughout primary production and processing. Provide training on good hygiene practices to all staff and eliminate the potential for littering and faecal contamination (e.g. in areas without sewerage systems or where open defecation is observed).

• Regulatory agencies and other relevant organizations should provide examples and training on how to use food safety plans and risk assessments to define water quality targets for fit-for-purpose water.

• Regulators, processors and consumers have a negative perception about the use of fit-for-purpose water. Strategies to overcome misconceptions should be considered.

• Some countries lack water management policies to protect and effectively use water sources. As safe water recycling and recuperation are currently improbable due to technical and financial barriers, ensuring the protection and sustainability of these sources should be of utmost importance. In remote areas, provision of water wells and toilets for the local population will further reduce the risk of human exposure to pathogens and help regulate access and use of water sources.

• Ensure that there is an adequate supply of drinking (potable) water and facilities for its storage and distribution to ensure the safety and quality of food.

Reference (open access)
FAO & WHO. 2023. Safety and quality of water used in the production and processing of fish and fishery products – Meeting report. Microbiological Risk Assessment Series, No. 41. Rome. https://doi.org/10.4060/cc4356en

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