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Assuring Water Quality and Safety in Food Processing (Part 4)

How do you go about interpreting water quality results?

Effects on Process Operations

Understanding water chemistry can benefit the processor in many ways. For example, baked goods do not contain large amounts of water but the chemistry of the water can affect doughs or batters, and eventually the finished baked good. Water acts as a solvent for salt, leavening chemicals, sugars, emulsifiers and all polar molecules.

Water may also contain dissolved minerals, organic matter, gases, and microbial contaminants. All of these factors are important to the bakery for overall quality assurance and sanitation. The amount and type of mineral salts present in water is very important to the baker. The degree of hardness is generally expressed as hard, soft, saline or alkaline. The specific composition is expressed in parts per million (ppm) of the dissolved hardness-causing minerals, mainly calcium and magnesium salts.

Cleaning and Sanitizing Water is almost a universal solvent. Flushing with water is the all-important first step in removing visible soil. According to Dennis Bogart of Randolph Associates, flushing is the most important step in cleaning. Bogart emphasized this point again and again at a recent symposium sponsored by the Institute of Food Technologists.[9] Cleaning compounds are used with water to enhance the cleaning ability of the water. Water carries detergents to the soil to be removed, it carries detergents and soils away from the surface and it can be used to sanitize a surface; assuming it is hot enough or contains antimicrobial compounds or sanitizers. Before selecting a cleaning compound, processors need to understand basic water chemistry and microbiology. Water used for cleaning should be of good microbiological quality.

The chemistry of the water, particularly water hardness, profoundly affects the performance of cleaning chemicals. Water hardness affects detergent consumption and may cause the formation of films, scale or precipitates on equipment surfaces. Failure to properly understand water chemistry can cost an operator money in both how much detergent is used and the time required for cleaning. Hardness is easy to measure, however, and is measured in grains or ppm.

When working with a supplier of cleaning compounds, be sure to be honest with them when they are developing your cleaning program. It is especially important to let them know if water is being drawn from multiple sources. The water chemistry from waters from different sources may differ significantly.

Water chemistry can also affect sanitizer performance. Chlorine is more effective at lower pHs. The lower the pH of the system, the more hypochlorous ion in the system, and hence, the greater the antimicrobial activity. If the pH of your water is 8.5, the efficacy of chlorination will be significantly reduced. If the water used is very hard, the processor may need to treat it. Water softening may be necessary for both processing and cleaning applications.

Plant Water Systems

Care must be taken when designing a factory to assure that there is not only enough water to meet the needs of processing, cleaning and employees, but that wastewater can be removed from the factory. This is something that needs to be done up front. If a plant adds production capacity without taking a close look at their water systems, significant problems can occur. The author has observed a factory whose toilets backed up and overflowed into the plant during peak production times. The wastewater systems simply could not handle both process water and sewage. It is a good practice to label all water and sewage lines. The use of colored tape, arrows or paint will provide plant personnel and visitors with a quick reference to what is flowing within the pipes and the direction of flow.

An integral part of wastewater disposal is the drains in the plant. Drains must be designed to not only handle peak water usage, but also to allow maintenance and cleaning. Of course, floors must be properly graded to allow drainage. The design and maintenance of floors and drains is a separate issue.

Operators also need to take look at their processes and products and be sure that the materials from which materials their pipes are manufactured are compatible. The one material that operators need to beware of is copper. Copper can be quite detrimental to certain foods and ingredients. Copper is a strong pro-oxidant, so it is not advisable to use copper if your foods are prone to oxidation. Copper will also react with certain flavors and ingredients. As an example, many years ago the author was involved in troubleshooting a problem on off-flavors in a blended product containing pineapple. It was determined that the copper water line to the blend tank added just enough copper to the product blend that the product quality began to deteriorate after a few days. The copper pipe was replaced with PVC and the problem disappeared.

Going With the Flow

Water is an integral part of almost all food processing operations, yet it is something that far too many operators take for granted. It can affect food safety, quality and sanitation. It is also the one material that each and every one of us needs to live. Processors need to understand how water is delivered to their plant, how it is removed, and the quality of the water entering the operation. Understanding water quality and how it moves through the factory is one part of the equation needed to produce safe, high quality foods.


This article was first published in Food Safety Magazine, and is reproduced with permission:  

About the Author
Richard F. Stier is a consulting food scientist with international experience in food safety (HACCP), food plant sanitation, quality systems, process optimization, GMP compliance and food microbiology. He has worked with a wide range of processing systems and products, including canning, freezing, dehydration, deep-fat frying, aseptic systems, and seafood processing. Rick served as Director of Quality Assurance for Dole Packaged Foods North American operations. In this capacity, he was responsible for building programs targeted at ensuring the quality of Dole value-added products packed in the U.S. While working on a USAID funded project in Egypt, programs and technical assistance provided by Rick’s technical services group resulted in more than 80 firms enhancing quality, safety and/or sanitation programs, which directly resulted in improved exports and an overall greater awareness of the importance of these three areas in international trade. He is a member of the Institute of Food Technologists and an editorial advisor to Food Safety Magazine. He can be reached at