Fish Microbiology and Quality Assurance

Unit 7 - Sanitation and microbiological quality

7.5. Process water quality
7.5.1. Water requirement
Water is an important requirement for any food processing industry and is required in large quantity. Likewise, fish processing industries too have a requirement for large volume of good quality water for various activities. All fish processing industries should have uninterrupted water supply of potable quality which is free from diseases causing organisms, toxic substances, and objectionable odour and taste. However, depending on the availability, the quality of water used for different purposes could vary. Since the sanitary quality of food is affected by the quality of the water, there is a need to use good quality water.
In a fish processing industry water is required for activities such a unloading and storage of small sized fishes, bulk storage of fish (Ex. Refrigerated seawater, brine, ice flakes), r cleaning purpose (cleaning of processing facility, equipments, containers etc), washing of raw material and processed material, product preparation, ice making, cooling, generating steam for cooking, blanching, retorting etc.

7.5.2. Sources of water
Waters of all sources can be utilized for use in processing industry. These may include surface waters, seawater, ground water and rain water.
Surface waters
Any surface water from sources such as rivers, streams, lakes and ponds can be used in fish processing industries. However, the availability and quality varies greatly depending on the source and season. Generally, stagnant waters such as lakes and reservoirs have less sedimentable debris than flowing waters (rivers). However, pollution of surface waters due to decaying plant and animal matter, industrial wastes, sewage, fertilizer and agriculture waste could affect water quality. These aters often require treatment before using.
Seawater
Most seafood processing units situated near sea often use seawater for cleaning purpose especially when freshwater is scarce. Use of seawater could cause problems such as corrosion of equipments, water pipes, fixtures etc., difficulty in treating and threats due to waves, tides, small sea animals and weeds in intake water. However, seawater could be an effective unlimited source only if used after desalination.
Ground water
Underground sources such as well water and spring water form an important source because of their better quality than surface waters. Contamination of ground waters from sewage and presence of high dissolved salts may require treatment before use. The availability of this source of water depends on the season and geographical location.
Rain water
Rainwater may be used in processing industries when available surface waters become scarce or unfit for use due to pollution. Rainwater is collected during times of heavy precipitation, stored and used with or without mixing with other sources of water supply. The collected water needs to be protected from contamination from birds, animals etc., and may often require treatment before use.

7.5.3. Water quality requirements
The water used in processing industry should be of potable quality. As large quantity of water is required for various purposes, it should not affect the quality of food and contaminate with harmful organisms. The water used should meet physical, chemical and microbiologiucal quality requirements.
The physical quality requirement for process water used in processing industries is that it should be free from any noticeable colour, odour, taste and undissolved material. The type and concentration of chemical substances dissolved in water contribute for chemical quality of water. Presence of higher concentration of calcium and magnesium salts contributes for extent of hardness of water. The use of soft water is recommended in processing industries as it does not affect product quality.
Microbiologically the process water contains natural water microflora and may or may not with human pathogenic microorganisms. The natural flora of water contaminates the product and may involve in spoilage under suitable conditions. The presence of pathogenic microorganisms in water is mainly due to contamination with domestic sewage. Thus, water should be treated effectively using standard water treatment procedures to make it free from pathogenic organisms.
The standards for water quality used in fish processing industries should ensure that the water is free from harmful microorganisms, deleterious and toxic chemicals and objectionable colour, odour and taste.