In recent years, advancements in wash water sanitation have created questions as well as answers. New developments have occurred both in the field and in research findings, leaving some companies to wonder how to decide which technology is best for them. I’ve increasingly fielded questions from buying companies as they consider rewriting product specifications to require use of one sanitizer over another. I’ve also received several calls from producers wanting to understand how to determine if they should change their systems. My purpose in this post is to highlight a few of the factors each company should consider in evaluating their wash water system.

The first step in evaluating any wash water scheme is to test the products in your system and validate what works in your specific operation. Validation is an extremely important concept. Past measures have often revolved around adding a sanitizer to water and then measuring the level of sanitizer at some time interval that meets a specific HACCP requirement. But, indirect measures of sanitizer (such as oxidation reduction potential) while convenient and continuous do not accurately reflect actual sanitizer levels, especially when organic loads accumulate during the production run.

In today’s world we must understand how effective a particular wash water system is in controlling the bacteria that could accumulate in wash water over a wide variety of treatment conditions and time. In evaluating whether new technologies will work for a specific operation, it’s crucial to conduct experiments on each possible technology. An operation must validate that the practices used for wash water sanitation actually achieve microbial control or reduce the risk of cross-contamination under the conditions typically encountered in their production environment. A generalized or “one size fits all” approach is simply not appropriate or effective.

From a buyer perspective, the key issue is not so much which program is being used, but rather if the system used by the suppler is validated. Can a supplier show the data that validates its treatments are working? And, can the supplier provide verification data demonstrating adherence to its wash water sanitation program?

Before employing or requiring any wash water sanitizer, it is important to fully understand how or if its use will improve product safety and wash water quality, change the microbial ecology of the finished product, impact the operational aspects of the process and affect quality of the finished product. 

Thus, in evaluating the efficacy of a new wash water sanitizer from a scientific perspective, several questions should be addressed. First, consider how effective the product is in controlling or killing suspended microorganisms (primarily bacteria and viruses) in the wash water and how its effectiveness could be impacted by organic load, material surface, pH, dwell time, or temperature. Then look at how the new sanitizer compares to other established wash water sanitizers and how the effective level can be monitored. Consider what the mode of action for the sanitizer is. What are the chemical, physical and biological interactions? Can they be reversed? What are the consequences of concentration?  Under what conditions is equilibrium achieved or lost? Lastly, is the product labeled as a processing aid or a disinfectant, sanitizer, pesticide, etc?  Has the product been approved by FDA and/or EPA?  Are the ingredients GRAS?

As far as microbial ecology goes, consider that all microorganisms might not be equally susceptible to the sanitizer. Look at how continued use of the sanitizer could result in the evolution of resistant microorganisms. In looking at operational impact, see if the sanitizer is effective under normal processing conditions.  Take into consideration the practical logistical aspects as well. For example, how is the sanitizer mixed and delivered to the wash system?  What are the training requirements? How versatile is the new sanitizer? What is the environmental impact of sanitizer use?  Will the sanitizer impact waste water removal?  Is the sanitizer compatible with the construction of your equipment?

Lastly, consider the finished product quality taking into account the impact on shelf life and if the postharvest physiology of the finished product changed. These are just a few of the many questions involved in truly analyzing a wash water system. For more details and a comprehensive list of the questions to consider, stay tuned for my Wash Water Paper being produced in 2012.

Remember, food safety is not passive, food safety is personal.  Each company must accept the responsibility to experiment and validate different technologies with its specific system. This is an area of developing technology and I look forward to sharing new development and information with you in future posts. Please contact me at AskDrBob@pma.com with any comments or questions. Your feedback is always valuable.

PMA’s Chief Science & Technology Officer, Dr. Bob Whitaker interviewed epidemiology expert, Dr. Michele Jay-Russell to introduce her to PMA members and provide a snapshot of her background and her passion for epidemiology.

BW: What drew you into epidemiology?

MJR: My interest in epidemiology probably started as a kid. I was always curious about animals and nature. I did my own little epi-investigation as a kid into die off of tadpoles in our neighborhood pond. After doing interviews, I discovered it was because a neighbor was putting gasoline and doing some dumping in the pond. So that was stopped. I always had a curiosity, and going into my education I was very interested in applying to veterinary school, but I didn’t take the traditional route as an undergrad. I went through medical entomology and theater as well as focusing on writing. Eventually I went into vet school and at UC Davis they have a combined program in preventive medicine and epidemiology, so I signed up for the duel degree program and knew that I would ultimately end up having a role in public health and doing epidemiologic investigation.

BW: What do you think is most misunderstood about the role of epidemiology in public health and the combination of art and science that makes up its practice? You did a great job writing these two companion papers, but what do you see most often as industry misperception of what epidemiology does?

MJR: I think the misperception relates to the strength of the association and the understanding of how statistics can be used. Having the science of epidemiology isn’t as straight forward as having for example a laboratory test. Not that all microbiology test are unambiguous but it is a lot easier to understand that you cultured E. coli O157:H7 out of a food or you didn’t versus discussing the nuances of an epidemiology investigation where you have outliers and statistical criteria. You have people that ate the contaminated food and didn’t become ill, and people who appeared not to have eaten the food and are part of the community and had an exposure. So the level of uncertainty in epidemiology is much greater than what you typically find in a standard microbiological test. Also, along that line, there is an expectation by some in the industry that you are always going to truly prove the cause of a foodborne outbreak. Sometimes that is just not possible because of the perishability of our products and the sampling limitations for testing for pathogen presence.  You have to rely on epidemiology and not having that laboratory result should not ever be an excuse not to protect public health if your epidemiology is strong. Where things get difficult is that not all epidemiology investigations are the same.  Some are stronger than others, some have weakness and uncertainty.

BW: Is there anything that makes fruits and vegetables more difficult when doing epidemiological studies versus another food group? I know that you have been involved across the board in different food groups. Is there anything about produce that is particularly different or any key learnings that you have gained over the years in cases where fruits and vegetables have been involved? 

MJR: The difficulty can be when you have an emerging vehicle or any food product that has not been seen before with a certain bacterial pathogen. For example, when strawberries were implicated with E coli. O157 earlier this year, that was not an expected vehicle. Also early on with sprouts, it took a number of repeated epidemiological studies before sprouts were actually linked to outbreaks. Some of that work was done in California by some of my colleagues, and one of their major clues was having a disproportionate number of women that were eating that produce item. The other part relates to what I was saying about having laboratory evidence. With milk, dairy, produce, and those items by time you identify the outbreak and start interviewing people that product can be long gone. And because contamination can be intermittent or in a short period of time, not ongoing, you may never isolate the implicated strain out of the food product.

BW: Ok switching gears, you just recently completed a PhD at UC Davis correct?

MJR: Yes, I did.

BW: Can you describe to PMA members what your current research interests are and how does that relate to some of the work you have done recently in the epidemiological field?

MJR: Well currently I am working as the project director in the Western Center for Food Safety at UC-Davis. I have been in this position for a little over 3 years now. The center was created with FDA to be what they call a “center for excellence” and is funded by CFSAN. Our center focuses on the interface with animal and plant agriculture as well as the environment. We in particular focus on pre-harvest food safety with an emphasis on produce. There is some dairy but the dairy component relates more towards manure management. So we do have strong produce research effort right now. Because I am a veterinarian, with a background in epidemiology, I am doing studies that primarily look at domestic and wild animals, and whether or not they are carries of foodborne pathogens, and what potential risks and mitigation strategies are available to prevent direct transmission of pathogens onto produce plants out in the field or to protect watershed from contamination by animals.

BW:  Thanks Michelle.  Also, thank you for preparing two excellent papers on epidemiology.  These papers can be found on pma.com in the “Information” section of the Food Safety Resource Center.

The 2011 Fresh Connections series on food safety is at an end. We accomplished six successful seminars covering major regions in the U.S. and I’ve gotten to meet and talk with dedicated industry professionals from all parts of the supply chain. As we draw this series to a close, it is important to reflect on what we learned from these six forums.

First, let’s look at what we learned from the presenters and the importance of truly understanding how to handle internal and external communication. We addressed how to communicate effectively with the outside world and especially with customers, about the expectations related to food safety issues. The sessions highlighted the importance of communicating internally with all employees on food safety and putting practices in place to actually measure success. 

We tackled the issue of communication and crisis management and the importance of having a crisis management plan in place. The role of people in sales, marketing and production was emphasized with respect to the worth they bring to support their company’s food safety objectives. People in the sales and marketing side are valuable tools to utilize when dealing with a food safety crisis.

Traceability is an integral part of any comprehensive food safety program, and we had a constructive update on the issues involving traceability and the Produce Traceabilty Initiative (PTI). Ed Treacy, PMA’s vice president of supply chain efficiencies, shared the most current information about the industry’s efforts to develop a common language for product coding and encouraged companies to meet the traceability challenge head-on.

However, perhaps even more valuable than the facts presented in the seminar was how the involvement of such a wide variety of people reflected our industry’s commitment to food safety. I was encouraged by the number of participants that attended these Fresh Connection events and those numbers reiterate the focus our industry has on taking food safety seriously.

As I observed the people that attended, their enthusiasm and interest reflected a sincere desire to delve into the topic and rise to the challenge. The level of questions posed and the depth of discussion demonstrated how people in our industry are doing a lot of thinking about food safety. They’re taking responsibility, looking for and finding solutions, and listening to key collaborators. We welcomed retailers, foodservice distributors, regulatory officials, state health department representatives, and third party food safety solution providers to share their perspective and experiences.

The participation from FDA and state officials was extremely beneficial. Anything we can do to increase exchange between the industry and those who regulate us is always positive. We had a chance to “look behind the curtain” and view things from a regulator’s perspective, including the challenges they face. That type of learning helps us better do our jobs. I’ve had a lot of positive response about the participation of these regulators and we’re very thankful that they are willing to take the time and engage with us.

While these Fresh Connections events resulted in a fair amount of engagement, they are in many ways just step one. The events provided a formal forum to engage various people across the industry at various points along the supply chain. However, of even greater value is how these events result in further correspondence by email, phone and in some cases direct visits to discuss food safety programs and address specific issues some companies might have. Personally, I find the connection I make with people whose food safety thinking has been stimulated to be the true merit of such events.

Although we’ve traveled this road for a while, the journey is really just starting. If you want to have an effective food safety program, you must be involved and educated. Our industry is fortunate to have available a wealth of resources including those from the Center for Produce Safety, agricultural extension, and local trade associations. You can also count on PMA for a variety of tools and information on food safety. If you’re interested in knowing more about what was presented at the Fresh Connections events, you can find my Fresh Connections food safety presentation on-line at the PMA Food Safety Resource Center. I look forward to even greater engagement with the industry as we continue to advance through this frontier of food safety.