ADVANCEMENT OF THE PRACTICE
Open Access
THE PRACTITIONER’S TOOL KIT
Field pH Monitoring 101
James J. Balsamo, Jr., MS, MPH, MHA, RS, CP-FS, CSP, CHMM, DEAAS Nancy Pees Coleman, MPH, PhD, RPS, RPES, DAAS
Brian Collins, MS, REHS, DLAAS Gary P. Noonan, CAPT (Retired), MPA, RS/REHS, DEAAS Robert W. Powitz, MPH, PhD, RS, CP-FS, DABFET, DLAAS Vincent J. Radke, MPH, RS, CP-FS, CPH, DLAAS Charles D. Treser, MPH, DEAAS
Editor’s Note: The National Environmental Health Association (NEHA) strives to provide relevant and useful information for environmental health practitioners. In a recent membership survey, we heard your request for information in the Journal that is more applicable to your daily work. We listened and are pleased to feature this column from a cadre of environmental health luminaries with over 300 years of combined experience in the environmental health field. This group will share their tricks of the trade to help you create a tool kit of resources for your daily work. The conclusions of this column are those of the authors and do not necessarily represent the ocial position of NEHA, nor does it imply endorsement of any products, services, or resources mentioned.
We admit that proficiency in conducting field measurements and the ability to feel comfortable when monitoring and interpret- ing findings during an inspection requires practice through trial and error. Here is our best advice for pH. As a start, familiarize yourself with pH val- ues of common foods and ingredients (see Sidebar). This knowledge shows us where and how to look. We begin assaying foods using prescreen- ing tools. For liquids and slurries, wide- range (1–14) pH test papers have numerous uses. The best test papers for food applica- tion are ones that measure pH between 3 and 5. If the food being tested obscures the color reaction after immersion, simply rinse the test paper with distilled or deionized water. For solid foods such as sushi rice, we prefer a liquid pH indicator that is applied directly on food that is placed in an easily cleanable and inert white porcelain well. The indicator responds to food pH and color change is vis- ible on the porcelain well. Most often, color indication is apparent, particularly when testing for a pH value ≤4.6. When the screening result is questionable, greater accuracy is required. To do achieve this accuracy, we rely on pH pens and por- table pH meters made specifically for food. Both pens and portable meters require cali- bration and care that is no more dicult or complex than validating thermometers, which we will cover in a little more detail later in this column. Whether prescreening or requiring a pre- cise reading, always measure “equilibrium” pH. Equilibrium pH is the pH of a food prod-
I t has been 20 years since pH and water activity (a w ) were introduced into the 2005 version of the Food and Drug Ad- ministration (FDA) Food Code . It broadened the definition of potentially hazardous food (PHF), now known as time/temperature control for safety (TCS) and included two pH and a w interaction tables in Chapter 1. Then, as now, tables in the 2022 Food Code show interaction between pH and a w in con- trol of spores in heat-treated packaged foods, and control of vegetative cells and spores in food not heat-treated or heat-treated but not packaged foods. After the introduction, it was hoped that this addition would be em- braced to meet inspection goals. Those of us who work with institutional, catering, and small artisan production kitchens welcomed the addition of pH and a w as a way to expand food safety where time, temperature, and hot/ cold holding facilities were at a premium and where unique cooking methods require addi- tional monitoring. The first reaction to our welcome came from FDA, whose spokesperson stated quite emphatically that this information was sim- ply meant as a guideline. With the emerging popularity of ethnic foods, new ingredients, and the introduction of some 33 dierent cooking techniques and processes, monitor-
ing pH and a w has taken on new significance, and TCS has taken on a broadened and updated interpretation. In a previous issue, we published a column about water activity (Balsamo et al., 2025). We will now try to tackle the other half of the TCS definition and hopefully give pH a greater role in our food inspection processes. We must admit that until recently, there was a lack of information about our inspec- tion application of pH and the use of field measuring tools for food. You will be amazed, however, at the information now available through a simple online search. University-based extension services (e.g., the University of Wisconsin, University of Georgia, Oklahoma State University), FDA, and manufacturers of pH color indicator and instrumentation devices provide exception- ally well-written information on all aspects of pH measurement. We are now comfort- able and confident in their use, particularly since many measurement devices are made specifically for food analysis. The selection of simple screening methods, including inexpensive litmus papers and solutions that rely on color change, has been greatly expanded. Field instruments like pH pens and portable meters are now specialized, user-friendly, and adaptable.
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Volume 88 • Number 2
https://doi.org/10.70387/001c.144005
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