Water Quality and Safety: Tips for Food Processors On Establishing Programs to Manage Water

Processors must establish specifications for water that is used as an ingredient and monitor water quality on a regular basis.

Water for Sanitation

Water is considered to be the universal solvent. The first step in most cleaning procedures is flushing to remove gross soil. Cleaning compounds are used with water to enhance the cleaning ability of the water. Water carries detergents to the soil to be removed, carries detergents and soils away from the surface, and can be used to sanitize a surface. Surfaces may be sanitized using hot water or a sanitizer that has been diluted in water.

The chemistry of the water, particularly water hardness and pH, affects the performance of cleaning chemicals. Water hardness affects detergent consumption and may cause the formation of films, scale, or precipitates on equipment surfaces. As an example, a cleaner designed for use in soft water may end up redepositing soil on the surface of the equipment if used in hard water (see Table 1). Failure to properly understand water chemistry can cost an operator money in both how much detergent is used and the time required for cleaning.

When working with a supplier of cleaning compounds, be honest with them as they work with you to develop your cleaning program. It is especially important to let them know if water is being drawn from multiple sources. The water chemistry of waters from each source must be fully understood. A reputable sanitation service/chemical supplier should do a water analysis for you before selecting chemicals.

Table 1

Water chemistry can also affect sanitizer performance. Chlorine is more effective at lower pH levels. The lower the pH of the system, the more hypochlorous ion in the system and, hence, the greater the antimicrobial activity. For example, if the pH of your water is 8.5, the efficacy of chlorination will be significantly reduced and….

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.

Water as a Transport Medium

Water is employed in many operations as a means to move products through the process. This is especially common with fruits and vegetables. The water used for this application often performs multiple functions. It cleans product, removing dirt and other soil, such as in tomato processing. Tomato processors unload gondola trucks into flumes, which convey the tomatoes into the plant and clean them in the process. These lines are usually built with collectors to remove mud and stones. The tomatoes are carried into the plant on conveyors and rinsed with water sprays in which chlorine levels are boosted. This operation is immediately upstream of the peelers, which usually use steam to loosen and remove the skin.

The water used to move and wash fresh-cut produce is an integral element for this industry. Water used for fluming fresh cut produce must include an effective antimicrobial, such as chlorine or peracetic acid, to prevent cross-contamination. In many operations, the processor sets up automatic monitoring systems that check pH and antimicrobial levels and will automatically signal meters to make adjustments to these two parameters.

One of the great myths in the industry is that adding antimicrobial to flume waters and maintaining that level makes fluming a “kill step.” Fluming or washing may reduce the counts on the product by one to two log cycles, but this reduction is due in large part to the physical action of the water in the washer or flume. The addition of antimicrobial maintains the microbiological quality of the water so this step in the process does not adversely affect the microbiological quality of the produce. A 2017 paper published in the Journal of Food Protection by Gombas and colleagues recommends three options for validating antimicrobial in wash water as a preventive control for leafy greens:

1. Use a surrogate for the microbial hazard and demonstrate that cross-contamination is prevented.
2. Use antimicrobial sensors and demonstrate that a critical antimicrobial level is maintained during worst-case operating procedures.
3. Validate the placement of antimicrobial sensors in the processing equipment with the demonstration that a critical antimicrobial level is maintained at all locations regardless of operating conditions.

Unfortunately, as noted in that publication and still true as of this writing, there are neither validated surrogates nor knowledge of critical levels for any commercially used wash water antimicrobials, so validating the effectiveness of these antimicrobials in a commercial operation remains an elusive goal.