Nuts, tomato sauce, or coconut milk: all examples of products with a shelf life of 5 months or longer. Typically, such long-life products remain safe to consume for some time even after their best-before date (BBD). “To prevent food waste and loss of revenue, food manufacturers frequently ask us for guidance on extending the BBD for these shelf-stable products. However, you cannot simply change the date on the label; it requires solid scientific justification. Sometimes we succeed in extending the shelf life from 6 months to 1 year,” explains Sylvia Mol, Microbiology Project Leader at Eurofins Food Safety Solutions. In this article, we explain how to approach extending a best-before date and what key factors to consider.
Whether extending a shelf life is feasible depends on several parameters, including ingredients, the manufacturing process, heating and cooling durations and temperatures, storage conditions, packaging methods, and any post-packaging pasteurisation. “Those parameters provide our starting point. In long-life products, it often turns out that very little happens regarding pathogenic microorganisms, with product deterioration over time being primarily sensory/organoleptic. We are, of course, referring to products with an extended BBD ('best before') of several months, not perishable products with a strict ‘use-by’ date (UBD) that must be consumed by a specific deadline. The NVWA states that you must thoroughly substantiate the BBD for such shelf-stable products. A microbiological risk assessment provides this scientific backing and ensures regulatory compliance. Simple statements like ‘we use modified atmosphere packaging’ or ‘we hot-fill the product’ are not sufficient,” Mol explains.
“Some time ago, a tomato soup manufacturer asked whether their products' shelf life could be extended from 6 to 9 months. That was ideal for their logistics, as the product would remain saleable even after the Christmas period. Through a microbiological risk assessment, we mapped out which intrinsic characteristics could trigger spoilage and confirmed that extending the BBD posed no food safety risk. We kick off such an assessment using analytical data on the product's chemical and physical parameters, such as pH and water activity, and occasionally moisture content, salt, or organic acids, depending on the product matrix.
The microbiological risk assessment is based on a scientific literature study, complemented where possible by predictive mathematical modelling. This allows us to evaluate whether a product's shelf life can be safely extended. These results provide a strong indication, but they remain theoretical estimates. If you want absolute certainty regarding whether a specific microorganism can grow in your product, you should perform a challenge test. Based on the formulation and the production process, we subsequently deliver an initial baseline estimate for the potential shelf-life extension.”
Why can’t you simply rely on end-of-shelf-life random sampling? “If a specific pathogen was not present in the batch immediately after production, you cannot evaluate its growth potential via end-of-shelf-life sampling alone. What isn't there cannot grow. Therefore, a negative test result from a single spot check reveals nothing about the shelf life of other production batches,” explains the microbiology specialist. “A comprehensive microbiological risk assessment validates the entire process and verifies that production controls are properly calibrated to keep microbiological risks under control. You know precisely which high-risk microorganisms could potentially proliferate in your matrix. That insight also delivers direct operational benefits. If the risk assessment reveals that only Salmonella presents a potential hazard, you only need to monitor that specific parameter going forward. You no longer have to run an exhaustive, costly testing suite throughout the product's shelf life, resulting in clear cost savings.”
If you produce multiple product lines, you can achieve additional cost efficiencies by grouping them into product clusters. Mol: “By establishing product categories and conducting a unified microbiological risk assessment for each group, you significantly reduce required testing. However, you must prove through chemical analyses that the grouped products share comparable pH and water activity values and undergo an identical manufacturing process. Only then can they be evaluated under a single framework. We regularly assist clients with this clustering process.”
A thorough microbiological risk assessment identifies which pathogens could potentially grow and produce toxins in your product, and calculates the severity and likelihood of that risk. The impact of the processing steps on these relevant pathogens is carefully evaluated.
Mol: “Recently, I evaluated the production line for a dairy-based product. The milk was heat-treated sufficiently to eliminate all vegetative microorganisms. Afterward, the product was cooled down and filled into containers. The filling process was the critical control point. Was the packaging material sterile? Could post-process recontamination occur during filling? Was it hot-filled? These are all factors we investigate. As the manufacturer utilised Ultra-High Temperature (UHT) processing and hot filling, we determined that post-process contamination was eliminated. Consequently, we were able to extend the BBD by 3 months, from 6 to 9 months.”
While a microbiological risk assessment may confirm food safety over an extended timeline, that does not mean a shelf life should automatically be prolonged. “You must independently verify whether the product maintains its taste, texture, and aroma after the extended period by conducting sensory evaluations or laboratory testing for spoilage microflora. Consider nuts becoming stale or the flavour profile of a tomato sauce shifting over time,” Mol notes. “The final sensory acceptability always remains up to the manufacturer to assess.”
Would you like to extend the shelf life of your shelf-stable product, or do you have specific questions? Contact Eurofins Food Safety Solutions via +31 (0) 888 31 03 30 or contractresearch@ftbnl.eurofins.com.