The previous article discussed the various decontamination options available to eliminate Listeria. It was explained why the physical properties of gaseous chlorine dioxide make it so effective. This article focuses on one company’s use of chlorine dioxide gas decontamination for both contamination response and for preventive control.
The summer of 2015 saw multiple ice cream manufacturers affected by Listeria monocytogenes. The ice cream facility detailed in this article never had a supply outage, but ceased production for a short amount of time in order to investigate and correct their contamination. After a plant-wide review of procedures, workflows, equipment design and product testing, multiple corrective actions were put into place to eliminate Listeria from the facility and help prevent it from returning. One such corrective action was to decontaminate the production area and cold storage rooms using chlorine dioxide gas. This process took place after the rest of the corrective actions, so as to decontaminate the entire facility immediately before production was set to resume.
The initial decontamination was in response to the Listeria monocytogenes found at various locations throughout the facility. A food safety investigation and microbiological review took place to find the source of the contamination within the facility in order to create a corrective action plan in place. Listeria was found in a number of locations including the dairy brick flooring that ran throughout the production area. A decision was made to replace the flooring, among other equipment upgrades and procedural changes in order to provide a safer food manufacturing environment once production resumed. Once the lengthy repair and upgrade list was completed, the chlorine dioxide gas decontamination was initiated.
The facility in question was approximately 620,000 cubic feet in volume, spanning multiple rooms as well as a tank alley located on a different floor. The timeline to complete the decontamination was 2.5 days. The first half-day consisted of safety training, a plant orientation tour, a meeting with plant supervisors, and the unpacking of equipment. The second day involved the setup of all equipment, which included chlorine dioxide gas generators, air distribution blowers, and a chlorine dioxide gas concentration monitor. Gas injection tubing was run from the chlorine dioxide gas generators throughout the facility to approximately 30 locations within the production area. The injection points were selected to aid its natural gaseous distribution by placing them apart from one another. Gas sample tubing was run to various points throughout the facility in locations away from the injection locations to sample gas concentrations furthest away from injection points where concentrations would be higher. Sample locations were also placed in locations known to be positive for Listeria monocytogenes to provide a more complete record of treatment for those locations. In total, 14 sample locations were selected between plant supervisors and the decontamination team. Throughout the entire decontamination, the gas concentration monitor would be used to continuously pull samples from those locations to monitor the concentration of chlorine dioxide gas and ensure that the proper dosage is reached.
As a final means of process control, 61 biological indicators were brought to validate that the decontamination process was effective at achieving a 6-log sporicidal reduction. 60 would be placed at various challenging locations within the facility, while one would be randomly selected to act as a positive control that would not be exposed to chlorine dioxide gas. Biological indicators provide a reliable method to validate decontamination, as they are produced in a laboratory to be highly consistent and contain more than a million bacterial spores impregnated on a paper substrate and wrapped in a Tyvek pouch. Bacterial spores are considered to be the hardest microorganism to kill, so validating that the process was able to kill all million spores on the biological indicator in effect also proves the process was able to eliminate Listeria from surfaces. The biological indicators were placed at locations known to be positive for Listeria, as well as other hard-to-reach locations such as the interior of production equipment, underneath equipment and inside some piping systems.
In order to prepare the facility for decontamination, all doors, air handling systems, and penetrations into the space were sealed off to keep the gas within the production area. After a safety sweep for personnel, the decontamination was performed to eliminate Listeria from all locations within the production area.
After being informed by its supplier Deutsch Kase Haus, LLC that its specialty Longhorn Colby cheese may be contaminated with Listeria monocytogenes, Sargento Foods, Inc. recalled several retail cheese products. The recalled Colby and Pepper jack cheeses (available on the company’s website) were packaged at Sargento’s Plymouth, Wisconsin plant. The company also recalled several other cheeses that were packaged at the same time “out of an abundance of caution”.
The recall involving Deutsch Kase Haus is not limited to Sargento. Guggisberg Cheese, Inc., Meijer and Sara Lee have recalled their Colby and Pepper jack cheeses. According to a release by US Foods, the product recalls were initiated after a notification by the Tennessee Department of Agriculture that some products manufactured on November 3, 10 and 18 could be contaminated with Lm.
Taylor Farms also recalled products that contained the cheese products—the company’s Class I recall involved 6,630 pounds of chicken and pork salad products that were produced and packaged from February 6–9, 2017.
Every year, FDA conducts thousands of food safety inspections and issues approximately 2,500 Form 483s to food companies. When the FDA investigators complete their inspection, they use the Form 483 to list the violations about which they are most concerned. Sometimes, if the violations are serious enough, and the company does not provide an adequate written response, FDA will send a follow-up warning letter threatening to shut the company down. The information contained in the 483s and warning letters issued to companies can be a useful tool to predict what FDA investigators will be looking for when they visit your own facility.
To see what FDA has been up to, we took a close look at some higher-profile 483s and warning letters recently issued by the agency.
Shawn Stevens will lead the webinar, “Who’s Getting FDA Form 483s? Recent Issues You Can Learn From” on February 23, 2017 at 1 pm ET Just recently, FDA issued a warning letter to a raw cookie dough manufacturer, threatening to shutter the company. The inspection was extremely extensive and lasted a total of eight business days. During the inspection, FDA investigators collected more than 100 environmental samples and tested them for the presence of Listeriamonocytogenes (Lm). Four of the samples, collected from a ladder, pallet jack and other non-food contact surfaces, were positive. The company also had a handful of recent positive Lm samples from its own in-house testing program. FDA insisted on access to the company’s own isolates and conducted whole genome sequencing on all the positive samples. The strains of the environmental samples matched, and FDA urged the company to recall all products produced over a four-month period. In the warning letter that followed, FDA warned the company that “it is essential to identify harborage sites in the food processing plant and equipment where [Lm] is able to grow and survive and take such corrective action as necessary to eradicate the organism by rendering these areas unable to support the growth and survival of the organism.”
This pattern is reflective of FDA’s new investigational approach during routine inspections. During a similar inspection of SM Fish Corp. last summer, FDA collected and tested 105 environmental samples (many of them taken from Zone 3 and Zone 4 areas, which were far-removed from the production of food) for the presence of Lm. When 29 of the 105 environmental samples collected tested positive for Lm, the agency withdrew the company’s registration and urged a massive recall. FDA adopted this aggressive stance even though no food contact surfaces or finished products tested positive for Lm during the routine inspection.
More recently, while FDA was performing a routine inspection of the Sabra Dipping Company, LLC’s manufacturing facility in Colonial Heights, Virginia, the agency adopted a nearly identical approach. After performing extensive microbiological sampling within the facility, the agency confirmed that 27 samples of more than 100 collected tested positive for Lm. Although none of the samples were collected from food contact surfaces or finished products, the agency nevertheless urged the company to announce a recall of hummus products that it had shipped.
These are just a few examples highlighting the significant consequences that can result from any routine FDA inspection. FDA is moving increasingly closer toward a zero-tolerance attitude toward Lm in the processing environment, and companies should heed the message contained in these most recent 483s and warning letters. With some careful preparation, you can avoid the mistakes of others and increase the likelihood that your own FDA inspection will end with much better results.
Building the right food safety culture around environmental monitoring requires a realistic approach to your processes. “Culture starts with understanding your process,” Zephyr Wilson, product manager at Roka Bioscience told Food Safety Tech at the 2016 Food Safety Consortium. “You need to ask questions—a lot of questions.”
In the following video, Wilson talks about food safety culture in the context of environmental monitoring and how companies should approach environmental monitoring. “Understand all of your processes,” she said. “Take an honest look at your metrics and make sure you’re encouraging your employees to find the Listeria.”
She also reviews the steps a company should take when undergoing self-auditing, and encourages companies to work under the direction of an attorney to ensure that all results are confidential.
“Drop the Mop! Take a Clean New Look at Condensation Control in Food Processing Facilities” is available on-demand Little beads of water on overhead surfaces can cause big problems. Remember the Listeria contamination that affected Blue Bell Creameries? FDA investigators spotted condensation dripping right into food and food contact surfaces. In a response to an FDA Form 483, Blue Bell wrote “As part of our internal review, we are extensively reconfiguring lines and equipment to eliminate the potential for condensation forming on pipes above processing equipment”.
Condensation can form on overhead surfaces during sanitation processes, which poses potentially serious issues. During an upcoming webinar, “Drop the Mop! Take a Clean New Look at Condensation Control in Food Processing Facilities”, experts from the University of Nebraska, Maple Leaf Foods, General Mills, Smithfield Foods, and 3M Corporate Research Materials Laboratory will discuss tips on how to manage condensation, along with the challenges associated with condensation.
Between 1996 and 2016, sprouts have been responsible to 46 outbreaks in the United States, which has led to nearly 2500 illnesses and three deaths, according to FDA. They have presented a consistent challenge to operators, because sprouts are most often produced in conditions that are ideal for bacteria growth.
Today FDA issued a draft guidance to assist sprout operators in complying with the FSMA Produce Rule, which requires “covered sprout operations take measures to prevent the introduction of dangerous microbes into seeds or beans used for sprouting, test spent sprout irrigation water (or, in some cases, in-process sprouts) for the presence of certain pathogens, test the growing, harvesting, packing and holding environment for the presence of the Listeria species or Listeria monocytogenes, and take corrective actions when needed.”
Large sprout operators must comply with the Produce Rule (applicable provisions) by January 26. Small business must comply by January 26, 2018 and very small businesses by January 28, 2019.
Any food facility that manufactures, processes, packs or holds ready-to-eat (RTE) foods should view FDA’s update on its draft guidance, Control of Listeria monocytogenes in Ready-To-Eat Foods. Consistent with FSMA, the draft focuses on prevention, and includes best practices and FSIS’s seek-and-destroy approach. Other recommendations include controls involving personnel, cleaning and maintenance of equipment, sanitation, treatments that kill Lm, and formulations that prevent Lm from growing during food storage (occurring between production and consumption).
“This guidance is not directed to processors of RTE foods that receive a listericidal control measure applied to the food in the final package, or applied to the food just prior to packaging in a system that adequately shields the product and food contact surfaces of the packaging from contamination from the food processing environment.” – FDA
The agency will begin accepting comments on January 17.
The 2016 Food Safety Consortium was a big success, from the preconference events that included the STOP Foodborne Illness fundraiser honoring heroes in food safety and the education workshops (SQF Information Day and preventive controls courses) to the record-breaking attendance we saw during the main program (with keynotes from FDA Deputy Commissioner for Foods and Veterinary Medicine Stephen Ostroff, M.D., Walmart’s Vice President of Food Safety Frank Yiannas, and FBI’s Special Agent Scott Mahloch).
As the event winded down, the leaders of each session track shared their insights on lessons learned during the Consortium.
Understanding biofilm and how it forms. If you’re seeing peaks and valleys in the positives and negatives in your environmental swabbing program, you may have resident Listeria that has formed a biofilm, which requires a deep clean. Focus on biofilm, not just mitigation of the Listeria bacteria itself. – Gina Kramer, Savour Food Safety International. Read Gina’s column, Food Safety Think Tank, where she talks about the latest technology and innovations.
This is the first conference I’ve been to you where food fraud is being more widely acknowledged as a serious, important concern that is distinctly separate from food safety. One of the more significant takeaways is the number of tools that are now available for people to mitigate their risk to food fraud in the supply chain. – Steve Sklare, USP
A while back food safety was a nice-to-have but not a need-to-have. It’s certainly an absolute need-to-have now. There are three groups of individuals out there: The third that has picked up the baton and is proactive, the other third that are in the middle of it right now, and the other third have their heads in the sand. I come across a sizable portion that is in the bottom third, and it’s slightly scary… It’s the documentation that a lot of companies are having the biggest challenge in dealing with—the death by paper. The resources out there are immense. It’s a necessity to have right now in order to be effective and compliant. – Warren Hojnacki, SGS
FSMA regulations require us to be risk based, scientifically based and systematic in our approach to our concerns and issues. – Barb Hunt, Savour Food Safety International
There’s potential for greater data and actions: i.e., the microbiome study or particulate contamination analysis, PLM, IR spectroscopy, SEM EDS, [and] raman spectroscopy…Lab customers may need to depend more greatly on contract labs as FSMA develops and in return, labs need to work more closely with the customers to get dependable, defensive data results. – Eric Putnam, Wixon, Inc.
We need to do a better job of messaging upstream to our corporate senior officials so we get the money and resources we need—there’s still a gap there. We need to find ways to communicate to them. – Trish Wester, PA Wester Consulting
Attend the Food Safety Supply Chain Conference, June 5–6, 2017 in Rockville, MD | LEARN MOREA recent study from The Hartman Group on the topic of transparency found that consumers are becoming more concerned about imports and the safety standards behind companies producing food and beverage products beyond U.S. borders.
So with the drastic rise in consumer expectations for food quality and safety in the past few years, how can companies ensure they’re mitigating risks in the supply chain while fostering transparency to meet consumer expectations?
To our benefit, the focus of the broader food industry and the government, as well as innovations in technology, are making it easier than ever to comprehensively track the supply chain.
Another Day, Another Food Recall, Another Listeria Scare
In today’s reality, whether we like it or not, food recalls are an inevitable part of the food industry, and adulteration in the supply chain is a key safety issue. With the wellbeing of consumers at stake, if a contamination finds its way into a brand’s supply chain, the best possible course of action is to take action on a recall using impeccable supply chain records and monitor the affected product moving throughout the chain.
With recalls being here to stay in the food industry, companies need to be prepared to handle these issues quickly and effectively. By implementing supplier management and whole-chain traceability software, allergens and impurities can be pinpointed to a specific lot of product as opposed to being limited to processing/issue date, and not knowing the source or country of origin of every ingredient (as many suppliers can contribute to one product) within the supply chain.
Additionally, with these technologies, brands can keep their supply chain transparent and compliant with growing industry regulations. With consumer standards on the line, proactive transparency can ensure that a company has a plan of attack when the inevitable hits.
A Targeted and Precise Plan
Companies and brands need to broaden their definition of food safety in order to manage and satisfy an expanded set of consumer expectations. The traditional, linear “one-up and one-back” (OUOB) approach to supply chain is no longer acceptable when it comes to comprehensive supply chain transparency.
Consumers need a targeted and precise plan when dealing with the safety of their food—it’s no longer just about whether the food safe to eat. The definition has expanded to include safety around ingredients and country of origin. Awareness of where a product came from and where it is going next is not an acceptable method if a company wishes to foster transparency with customers and effectively manage recalls. In addition, these standards are emphasized by federal regulations like the FSMA and FSVP—the industry is now shifting towards preventative approaches to safety matters, as opposed to reactive. FSMA requires food manufacturers to increase focus on prevention rather than response to contamination incidents, which will require a comprehensive view of the entire supply chain.
Brands will need to develop strong food safety plans with streamlined audits and compliance records, verifying supply chain partners and executing corrective actions for suppliers that are not in compliance with the process and food safety plan set in place. In establishing this process, having the technology to support it is paramount in ensuring that suppliers are sticking to the food safety practices necessary to follow industry regulation and exceed consumer expectation.
Transparency in Today’s Complex Food Paradigm
As the global food supply continues to grow in volume and complexity, brands have an opportunity and an obligation to adapt to the food paradigm. According to a Label Insight study, 94% of consumers say transparency from food brands is the #1 factor that impacts purchase. Brands are no longer able to blame a supplier’s lack of transparency or unreliable records for exposing consumers to unsafe products but instead, the brand is solely held accountable.
Transparency and proactivity were optional in the past, but are now established as fundamental components of a brand’s safety plan if they are to adapt to the changing industry landscape as well as consumer demand. As recalls are bound to happen, proactivity and transparency can ensure that a company is one step ahead of an outbreak at all times.
The fact is, adapting to this shifting environment and aligning with these best practices and the technologies that enable them is critical to the success of the supplier, distributor and across the whole supply chain. Food companies must look to utilize big data analytics and intelligent supply chain mapping technologies in order to improve transparency and increase traceability. With the ability to track ingredients back and forth across the supply chain, these technologies enable a safer consumer experience as well as provide tremendous business value in eliminating inefficiencies, managing supply chain issues, and effectively protecting the brand with the insights offered.
Anyone who has attended a food safety conference in the last few years has experienced some type of whole genome sequencing (WGS) presentation. WGS is the next big thing for food safety. The technology has been adopted by regulatory agencies, academics, and some food companies. A lot has been said, but there are still some questions regarding the implementation and ramifications of WGS in the food processing environment.
There are a few key acronyms to understand the aspects of genomics in food safety (See Table I below).
Pulse Field Gel Electrophoresis
Technique using restriction enzymes and DNA fragment separation via an electronic field for creation of a bacterial isolate DNA fingerprint; PFGE is being replaced by WGS at CDC and other public health laboratories
Whole Genome Sequencing
The general term used for sequencing—a misnomer—the entirety of the genome is not used, and depends on the analytical methodology implemented
Next Generation Sequencing
NGS is the next set of technology to do WGS and other genomic applications
Single Nucleotide Polymorphisms
A variation in a single nucleotide that occurs in specific position of an organism’s genome; Used in WGS as a methodology for determining genetic sameness between organisms
Multilocus sequence typing
A methodology for determining genetic sameness between organisms; Compares internal fragment DNA sequences from multiple housekeeping genes
16s RNA sequencing
A highly conserved region of the bacterial genome used for species and strain identification
Joseph Heinzelmann will be presenting: Listeria Testing Platforms: Old School Technology vs New Innovative Technology during the 2016 Food Safety Consortium | LEARN MOREIn 1996, the CDC established the PulseNet program for investigating potential foodborne illness outbreaks. PulseNet has relied on using bacterial DNA fingerprints generated via PFGE as comparisons for mapping potential sources and spread of the outbreaks. Due to a number of advantages over PFGE, WGS is quickly becoming the preferred method for organism identification and comparison. Moving to WGS has two critical improvements over PFGE: accuracy and relatedness interpretation. Like PFGE there are nuances when defining the difference between two very closely related organisms. However, instead of defining restriction enzymes and comparing the number of bands, the language changes to either single nucleotide polymorphisms (SNP) or the number of alleles. The other important aspect WGS improves is the ability to determine and interpret the relatedness of organisms more broadly. The frequent Listeria outbreaks and incidence from 1983-2015 provide an insight to what the future might hold with WGS implementation.1 The incidence report shows the increased ability to quickly and more accurately define relatedness between clinical cases creates a link of potential cases much faster.
WGS also provides key practical changes for outbreaks and recalls in the food industry. Sequencing provides a much faster response time and therefore means the outbreaks of foodborne illness decrease, as does the number of cases in each outbreak. As the resolution of the outbreaks increases, the number of outbreaks identified increases. The actual number of outbreaks has likely not increased, but the reported number of outbreaks will increase due increased resolution of the analytical method.
WGS continues to establish itself as the go-to technology for the food safety agencies. For example, the USDA food safety inspection service recently published the FY2017–2021 goals. The first bullet point under modernizing inspection systems, policies and the use of scientific approaches is the implementation of in-field screening and whole genome sequencing for outbreak expediency.
Agencies and Adoption
The success of FDA and CDC Listeria project provides a foundation for implementation of WGS for outbreak investigations. The three agencies adopting WGS for outbreak investigations and as replacement for PulseNet are the CDC, FDA and USDA. However, there are still questions on the part of the FDA for when WGS is utilized, including under what circumstances and instances the data will be used.
In recent public forums, the FDA has acknowledged that there are situations when a recall would be a potential solution based on WGS results in the absence of any clinical cases.2 One critical question that still exists in spite of the public presentations and published articles is a clear definitions of when WGS surveillance data will be used for recall purposes, and what type of supporting documentation a facility would need to provide to prove that it had adequate controls in place.
A key element is the definition between agencies for sameness or genetic distance. The FDA and FSIS are using a SNP approach. A sequence is generated from a bacterial isolate, then compared with a known clinical case, or a suspected strain, and the number of different SNPs determines if the strains are identical. The CDC is using the Multilocus sequence typing (MLST) approach.
Simple sequence comparisons are unfortunately not alone sufficient for sameness determination, as various metabolic, taxa specific and environmental parameters must also be considered. Stressful environments and growth rates have significant impact on how quickly SNPs can occur. The three primary pathogens being examined by WGS have very different genetic makeups. Listeria monocytogenes has a relatively conserved genomic taxa, typically associated with cooler environments, and is gram positive. Listeria monocytogenes has a doubling time of 45–60 minutes under enrichment conditions.3 These are contrasted with E. coli O157:H7, a gram negative bacteria, associated with higher growth rates and higher horizontal gene transfer mechanisms. For example, in an examination of E. coli O104, and in research conducted by the University in Madurai, it showed 38 horizontal gene elements.4
These two contrasting examples demonstrate the complexity of the genetic distance question. It demonstrates a need for specific definitions for sameness within a microbiological taxa, and with potential qualifiers based on the environment and potential genetic event triggers. The definitions around SNPs and alleles that define how closely related a Listeriamonocytogenes in a cold facility should be vastly different from an E. coli from a warm environment, under more suitable growth conditions. Another element of interest, but largely unexplored is convergent evolution. In a given environment, with similar conditions, what is the probability of two different organisms converging on a nearly identical genome, and how long would it take?
MLST vs. SNP
As previously stated, the three agencies have chosen different approaches for the analytical methodology: MLST for CDC and SNP of the FDA and USDA. For clarity, both analytical approaches have demonstrated superiority over the incumbent PFGE mythology. MLST does rely on an existing database for allele comparison. A SNP based approach is supported by a database, but is often used in defining genetic distance specifically between two isolates. Both approaches can help build phylogenetic trees.
There are tradeoffs with both approaches. There is a higher requirement for processing and bioinformatics capabilities when using a SNP based approach. However, the resolution between organisms and large groups of organisms is meaningful using SNP comparison. The key take away is MLST uses a gene-to-gene comparison, and the SNP approach is gene agnostic. As mentioned in Table 1, both approaches do not use every A, T, C, and G in the analytical comparisons. Whole genome sequencing in this context is a misnomer, because not every gene is used in either analysis.
Utilizing WGS for companies as a preventive measure is still being developed. GenomeTrakr has been established as the data repository for sequenced isolates from the FDA, USDA, CDC and public health labs. The data is housed at the National Center for Biotechnology Information (NCBI). The database contains more than 71,000 isolates and has been used in surveillance and outbreak investigations. There is a current gap between on premise bioinformatics and using GenomeTrakr.
The FDA has stated there are examples where isolates found in a processing facility would help support a recall in the absence of epidemiological evidence, and companies are waiting on clarification before adopting GenomeTrakr as a routine analysis tool. However, services like NeoSeek, a genomic test service by Neogen Corp. are an alternative to public gene databases like GenomeTrakr. In addition to trouble shooting events with WGS, NeoSeek provides services such as spoilage microorganism ID and source tracking, pathogen point source tracking. Using next generation sequencing, a private database, and applications such as 16s metagenomic analysis, phylogenetic tree generation, and identification programs with NeoSeek, companies can answer critical food safety and food quality questions.