Assuring Water Quality and Safety in Food Processing (Part 2)

Most people take water for granted. In the United States, Japan and in Western Europe, all that an individual needs to do is turn on the tap at any time in the day or night to get clean, potable water. Part 2 of this article considers the uses of water.


The water must also be delivered to different areas within the plant at with sufficient pressure to do the job that needs to be done. For example, if a line contains a washer or washing step, the water pressure must be high enough to properly wash the product or unit operation. Operations that have problems with poor water pressure may be forced to install hold tanks with pumps to assure both adequate supply and pressure.

Most food processors use hot water for cleaning and other operations. Processors need to assure that they establish systems that allow them to heat sufficient quantities of water for all their needs. Ideally, these systems should allow them to control temperature to within the necessary parameters. For example, cleaners work best within set temperature ranges. If an operation is involved with the production of meat or meat products, U.S. Department of Agriculture (USDA) regulations mandate that there be sanitizing stations where the water is held at 82F or above to assure that utensils may be properly sanitized.

The first step for a processor is to be sure that there are complete and updated plumbing diagrams. Processors need to understand how fresh water comes into the factory, its source and, perhaps, most important, that there are no cross-connections with sewage or waste water lines. This is something that most new plants would have, but is not as common in older facilities. Understanding water and wastewater flow is absolutely essential. The plant engineers and/or maintenance people should conduct an internal audit to verify that plumbing diagrams are accurate and up to date. Experience shows that as plants expand or are modified, these operations tend not to make the necessary changes to their plumbing blueprints.

Processors should also examine all water lines and water handling systems to be sure that there is no potential for contamination within the operation. Do you have back-flow prevention devices on water lines? Are there air gaps between spigots or hoses and water sources? Are hoses handled properly so that their use in the process will not contaminate product, equipment or ingredients? Operators need to teach plant staff how to handle and store hoses. Line workers often drag hoses across the floor, over equipment and use them to fill blending or mix tanks. Wastewater and soil end up in the mix. Perhaps the greatest potential concern for contamination is cross-connections. Processors need to verify that plumbing diagrams are both accurate and current. The diagrams should show no cross- connections.

As noted, processors should conduct an audit of their water and plumbing systems. Such an audit will also help processors determine whether there are any “dead spots” or deadends in the lines. Water lines remain clean because they are constantly flushed. Unused lines off a main or a large reservoir below the floor will not be flushed properly. Water remaining in these dead areas can create potential health and quality problems. For example, a processor who relies on clean water for blending might experience off-flavor problems if there is a dead spot upstream of the blend tanks. Back-flow devices are designed to prevent dirty or contaminated water from flowing towards a clean source. They allow water to flow in one direction only. Operators must check to see that these are on lines as they can “disappear.” Air gaps are also basic good sanitary design. Water sources and tanks must be separated.

Indeed, back-flow prevention has become a hot button in third-party audits. The plumbing diagrams alluded to earlier should include all water systems and the locations of the back-flow devices in the system. Ideally, these devices should be included in a plant’s preventive maintenance program. There should also be an easily accessible back-flow device on all water mains coming into the plant. There are plants where the lines are under ground and, therefore, inaccessible. Yet, these plants tell the auditors that they are “checked annually.” In point of fact, there are many states where it is mandatory that a food processor contract with an outside firm to validate that the back-flow devices on their water mains are functioning as designed. These companies conduct pressure tests on the devices and make any adjustments that are needed. Their report will also serve as an auditable record to ensure that the work is being done.


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