Foreign Material and Off-Odor and Flavor Testing: Sources of Contamination
Have you ever uncapped a drink only to find strange black particles floating around or opened a yogurt with an unpleasant smell and tangy taste? Foreign materials and off-odor or flavor complaints can spoil a product and damage a brand’s reputation. In the worst cases, they can be unsafe and cause harm to customers. Testing for contamination, processing, and production errors is the key to avoid these outcomes and produce high-quality, reliable products.
There are many benefits to foreign material and off-odor/flavor testing, including increased quality, performance, and label claims, improved brand reputation, and identification of affected products prior to distribution. On the other hand, failing to test your product can result in food fraud, packaging failures, legal action, or harm to consumers, which collectively contribute to a negative brand image and can even be dangerous.
Improving product quality and consistency starts at the very beginning; testing raw ingredients and materials is the first step to ensuring untainted and safe products. Even with trusted suppliers, it is critical to evaluate materials before product production each time a new lot is obtained.
If the raw materials meet your specification, the next step is a critical evaluation of packaging and processing procedures.
Packaging issues:
Understanding your product is essential to determining the best packaging procedure – packaging incompatibility is a common source of materials and aroma issues. For example, a product with high acidity can degrade aluminum or the wrong kind of ink can bleed through the packaging and onto a product, otherwise known as leaching. Improperly packaged products can also lead to degradation, especially with light or heat-sensitive materials or nutrients. To ensure the optimal packaging procedure is in place, perform analytical and quality testing with packaging options in different storage conditions.
Production issues:
Production issues often contribute to foreign material and off-odor/flavor complains. The figure below shows examples of production issues. Other sources can include improper cleaning or sterilization. Prior to distribution, batch or lot testing is typically performed to ensure nothing unexpected has ended up in the final product. In other words, testing is not a one-and-done event; it must be done consistently and often.
Chemical and microbial contamination:
Chemical contaminating your product can range from cleaning solutions to lubricants from machines during packaging. No matter the source, chemical contamination can result in product degradation and loss of quality and lead to toxic materials reaching consumers. Contamination can alter the smell and taste of a product and lead to undesired texture and material changes. Sources of chemical contamination include storage issues (like leaching from a holding tank or packaging), improper cleaning, or user errors (like excess lubrication used on an instrument in the production line).
Microbial contamination can lead to biofilms or microbial colony growth and unpleasant aromas in all kinds of products. Improper storage temperature, poor hygiene and improper handling, cross contamination, or processing failure (like incomplete pasteurization) can result in microbial contamination.
Testing for contamination before products reach shelves is important to protect customers and maintain a reputation for high-quality goods. By utilizing personalized testing plan, you can stop product contamination and identify the source or location of contamination from the start.
Testing approaches to detect and identify foreign materials and off-odors or off-flavors
A selection of tests exist to identify foreign materials and off-odor or flavors and their sources in the manufacturing process. Each test described below provides a different insight into the chemical, physical, or structural components of a substance, so they are usually used in combination. The right testing laboratory will have the expertise to formulate the ideal testing plan for every product and will tailor them to each situation, as they are all unique.
Testing options include:
- Imaging: The first method used for foreign material identification is always imaging. Sometimes, a simple macroscopic picture is enough to identify an object. More often, a microscopic image, collected via light or electron microscopy, provides more vivid structural detail, which hints to a material’s identity. Scanning electron microscopy (SEM) uses an electron beam to scan the surface of solid objects to provide an image of the microscopic topography of an item. SEM combined with energy-dispersive X-ray analysis (SEM-EDX) generates both topology and chemical distribution information in a non-disruptive imaging approach. Imaging is sometimes applicable for off-odor and flavor analysis when a visual cue (like a biofilm or foam) is present.
- Spectroscopy: Spectroscopy uses light waves to analyze the chemical composition of an unknown material. Light of a specific wavelength (which isn’t always visible to the human eye) passes through the object and the patterns of refraction, absorption, and transmittance are used to determine the unique chemical makeup of the material. Fourier-transformed infrared spectroscopy (FTIR) is often used for large, bulk materials, and microFTIR is used for small particles, which means spectroscopic approaches are not limited by sample size or availability. Notably, Raman spectroscopy can measure water soluble materials, even through glass or plastic bottles.
- Thermal Analysis: Thermal analysis, including Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA), can illustrate phase changes like melting point, softening point, and crystal structure. These techniques can also determine if a product has been exposed to temperature extremes (e.g. freezing, boiling at 100-120C during a retort process) which may be indicative of failure mode or cause of foreign material in the product or packaging
- Inductively Coupled Plasma (ICP): ICP is a common technique for elemental detection. This method uses a laser to excite elements and measures the energy emitted as they return to their neutral state. ICP is coupled with either optical emission spectrometry (ICP-OES) or mass spectrometry (ICP-MS) depending on the range of compounds and their detection limit. This is an exceptionally useful approach for nutritional mineral measurement and metal detection.
- Chromatography: Liquid and gas chromatography are standard methods for measuring chemical constituents in a sample. Liquid chromatography is most useful for non-volatile compounds, like organic acids, proteins, dyes, or sugars, while gas chromatography is best for volatile compounds, like solvents or oils. In either case, coupling chromatography with mass spectrometry or another detector allows for the quantification of compounds for foreign material identification. Gas chromatography is particularly useful for off-odor and flavor analysis, since volatile compounds are associated with aromas.
- Microbial screening/DNA analysis: Sometimes a foreign material or off-odor/flavor issue in a product is the result of microbe contamination. Not all microbes are harmful to consumers, but it is never worth the risk to omit this testing. In some cases, microbes can cause biofilms or thick clumps that ruin a product. Microbial screening includes growing the microbe in/on different media types in various conditions to determine the composition based on growth habits. This can be coupled with DNA analysis, like 16S PCR or metagenomics, for a more specific identification.
- ELISA/ICT assays: ELISA and ICT are both assays used for evaluating protein and protease characteristics using specific antibodies. These, and similar, assays are used to determine if foreign materials are a result of guar/xanthan gum or other thickening agents or if off-odor/flavors are associated with protein based contamination.
No matter where you are in the production process, it is a good time to start preventative foreign material and off-odor/flavor testing. Testing early and often is the best way to prevent future issues. At Eurofins, we have the experience and expertise needed to create the right testing plan for you. Contact us today at ESFA_Project@eurofinsus.com or call +1 (262) 754-5300 extension 3 to learn more!
