End users of food packaging: Beware, be forewarned and be ready to make use of functional opportunities to proactively identify and solve product-package interaction risks such as scalping and migration.       

The editors of Packaging Digest sent me a release recently advising that Stephen Klump, Ph.D, Nestlé S. A., global technical expert for Packaging Quality & Safety, will be a panel member discussing the subject of food packaging “migration” at the May 2016 RadTech Conference in Rosemont, IL.

I do not know Dr. Klump personally, but his reputation and expertise in the disciplines of packaging scalping, migration, material suitability characteristics and related test methodologies are exceptional. Under his direction, Nestlé applies a cutting-edge approach to package/product interaction, combining practical techniques and scientific principles to develop, improve and implement test protocols and methodologies designed to control packaging materials quality and identify non-conformances. Their processes are surely destined to become benchmarks in the food industry.

Within the discipline of packaging science, migration is the term used to describe physical and/or chemical transfer of odors, flavors and components from packaging materials into the food products they contain. Physical and chemical mechanisms which facilitate migration vary based on multiple factors such as packaging material systems, foods, processing, storage, handling and others. A related product/package interaction risk mechanism is scalping, wherein packaged food volatiles or components are absorbed or through uptake are drawn into the packaging material(s); for example, when flavor-rich components transfer from a citrus product to the packaging, leading to accelerated reduction in product flavor impact, leading to accelerated reduction in product flavor impact and possible consumer dissatisfaction.    

Not all migration and scalping encounters and mechanisms are undesirable. Under controlled conditions, packaging structures are designed and engineered to intentionally migrate targeted materials into a product or scalp (attract, absorb, remove or facilitate the egress of) unwanted substances from the product or headspace. Examples include the controlled migration or introduction of preservatives, hosted by packaging, into the contained food to improve shelf-life and product quality, as well as the use of active scavengers to attract and absorb undesirable substances (e.g. oxygen, carbon dioxide) from the food or package headspace.

The emphasis of this article focuses on unwanted and deleterious instances of migration and scalping and opportunities to identify same in advance of an unwanted and costly in-market failure.  

Migration is one of the more insidious product/package interactions, in the event that unwanted components evolve into the contained food, ingredient, intermediate or package headspace. Language can be found in 21CFR [174.5(b)] and the Food, Drug and Cosmetic Act [402(a) (3)] referencing regulated food packaging found to have imparted odors or flavors to a specific food. Regardless of technical determination as to whether any specific package material or component is under direct or indirect control from federal regulations, including FSMA, no seller or user of consumer packaging desires to grapple with interpretive scope or be forced to distribute self-serving denials when faced with a suspected packaging-related product non-conformance.   

The development and maintenance of safe, quality packaged foods is based on process “ownership” partnerships facilitated by qualified representatives from each internal and external support function. Traditionally, that partnership is composed of a product developer and a packaging technologist supported by internal QC/QA and production representatives as well as (external) vendor technical support. Together, they form a team responsible for developing, commercializing and continuously monitoring the quality of packaging, food and the combined finished product-in-package. 

Wide-reaching control and influence across these combined functions creates multiple opportunities to observe, communicate and react to product-package interactions or defects such as scalping and migration, some of which may affect consumer safety and/or product suitability.  Specific opportunities exist following:    

(1)   Preliminary plant trials I sponsored by “R&D” with support from Quality, Operations and key vendor representatives. These activities provide an opportunity to perform experiments designed to assess the effectiveness and performance of food formulations, packaging components and commercial equipment process variables. During plant trials, experimental variables or iterations can be added, removed or adjusted based on team observations and dialogue.

Upon conclusion, representative “time-zero” samples of each packaged product variable are collected, analyzed and control-tested.  Additional representative packaged products are placed into multiple, controlled storage conditions (time, temperature, humidity, altitude, compression etc.).  Samples are withdrawn at meaningful intervals, then evaluated and analyzed. Results are compared against time-zero results and various quality expectations.

As the evaluation process progresses, sample combinations may be removed from consideration due to incompatibility, ineffectiveness or some other aspect that fails to meet targeted expectations or technical criteria for success. Sometimes, those failures are caused by observed scalping of flavor or migration of components into the food or headspace, identified via organoleptic evaluation and confirmed following state-of-the-art rapid throughput chemical analysis.

(2)   Focused plant trials II of packaged product “finalists” composed of limited variants using production-equivalent materials and equipment. Again, finished packaged samples are subjected to another round of testing and analysis over a longer period of time and once again, sensory, analytical or machinability trial failures may disqualify particular products or packages from achieving commercialization.

(3)   Limited production runs using packaging and product which may be released to the trade for sale to consumers if all criteria for success are met and the Business Team agrees. Every variable is production-equivalent. Yet again, samples from these trials are placed in multiple storage conditions and subjected to shelf-life studies. Results are compared against observations from past studies and current or selected benchmarks.  If scalping and/or migration tendencies or precursors are observed or determined following evaluation or analysis of samples subjected to accelerated or abusive storage conditions, corrective actions may be made prior to extended production runs and broad trade release. 

(4)   Receipt of production packaging component lots, sampled by a packaging materials intake resource at the end-user manufacturing facility. Sensory and physical characteristics of representative production lot samples can be evaluated against and compared to valid reference standards in order to identify non-conforming packaging components prior to production use. Questionable lots may be placed “on hold” and undergo vendor testing in order to confirm suitability. This is a good packaging “best practices” opportunity to further evaluate packaging quality and safety, however resource limits and other challenges may preclude this process from being performed at the end-user production facility.  

(5)   Quality analysis of finished packaged product case samples obtained across the production day.  Plant QC collects random cases of packaged products during production. Product, headspace and packaging are each assessed against standards. Questionable results allow production lots to be embargoed and broader component tests to be performed before product is shipped to customers.  The limited value of these types of tests is that they are performed within 24 hours of production. Typically, only the most obvious or egregious defects are identified so soon after production. 

(6)   The collection and analysis of field audit products, possibly the most comprehensive post-production opportunity to identify evidence of scalping and/or migration. If packaged product test results from number 5 above are unlikely to uncover negative product/package synergies which take time to evolve, field audit samples may be the most likely. The benefits of securing samples from the “field” (customer warehouses, store shelves, manufacturer distribution centers) combine three critical variables:

In the event that analysis of field audit samples uncovers an unwanted, unexpected or undesirable product/package interaction, there are still going to be logistical and financial impacts associated with market withdrawal and/or recall, but probably not to the extent encountered when non-conforming goods are identified by consumers and communicated to the media or regulatory agencies.

Migration can be driven by a multitude of factors.  Some of the causes that I’ve encountered include:

A final product-package interaction risk is offered for your consideration. It has the potential to exist for any product or package, to extents which vary.  Thus, the risk severities and impacts upon occurrence vary widely, as described in this example: R&D performs its due diligence converting finished trial products-in-packaging using production-identical materials and equipment.  Samples from those production-equivalent runs are placed into multiple storage conditions and subjected to shelf life testing (organoleptic, visual and analytical chemistry).  Time-zero samples match standard references, line samples removed and tested by QA are perfect and the marketing “show and tell” concludes with all qualitative criteria being achieved. Approval is given to release the converted products for sale.

All steps appear to have been properly performed, however, in this scenario, the trials were based on an n that is statistically non-predictive.  One lot of each raw material was used to make the product, one lot of packaging components were converted using one lot of resin or film, one lot of hot melt carton and case adhesive was used to seal secondary packaging, one shift of production was overseen by one operator packed on one line evaluated by one product developer, one packaging engineer and one QC tech. If those efforts conclude with perfection, how may the results differ as production variables broaden?  

Problems are inevitable

History shows that even the most consistent and reliable product-in-package combinations will eventually encounter a quality deviation. The presumptions of “low risk” and “nothing changed” have fooled many a seasoned supply chain professional. With today’s limited resources, speed-to-market, extensive product versioning, corporate contractions and such, quality-impacting factors within each supply chain are bound to change, at times without prior notice to the end user. Supplier “X” is sold or merges manufacturing locations, the conversion process is changed, the packaging machinery is “adjusted” or retrofitted, a new ingredient is added, a “slight” change in the “slip package” formulation is made, the elastomer content is “increased slightly” to compensate for a reduction in the values obtained from the latest polystyrene puncture-resistance tests, the UV ink curing system malfunctioned and so on and so forth. 

Each organization has to grapple with the inevitability of those risks and the potential impact to the organization if the product/package system balance is negatively affected.  Oversight by the end user cannot be replaced alone by vendor diligence, because only the end user has access to the most comprehensive objectives and information. Therefore, unfortunate as is may be, end user quality oversight is placed in the hands of the functions with the knowledge and ability to assess and adjust on an ongoing basis. The lead entity on the functional team, based on technical capability, is R&D management. With ever-shrinking resources and lean manufacturing principles, it all becomes a daunting challenge, yet one that must be properly considered and addressed in order to apply adequate levels of control to mitigate the risks and impacts of scalping and migration.

Gary Kestenbaum has 40 years’ experience in the food and packaging industries, six as a supplier with National Starch, 18 as a product developer with General/Kraft Foods and 15 as a packaging engineer and developer with Kraft. As senior food packaging safety consultant with EHA Consulting Group, Kestenbaum provides guidance on packaging safety and suitability-related projects for raw material manufacturers, converters and associated supporting professionals. He can be reached at [email protected] or 410-484-9133. The website is www.ehagroup.com.