Know: Product Shelf Life Determination

Sector-Specific Information

The Food Industry Hub knowledge centre delivers a wide range of sector-specific information for food industry professionals.

The below is one topic from our knowledge centre. You can return to all topics by clicking here.

Product Shelf Life Determination

Introduction

Product shelf life refers to the period during which a food product remains safe to consume, retains its desired sensory qualities (such as taste, texture, appearance, and aroma), and meets nutritional and safety standards. Determining the shelf life of a food product is crucial for food manufacturers to ensure consumer safety, compliance with regulatory standards, and product quality. Proper shelf life determination also plays an essential role in inventory management, waste reduction, and consumer satisfaction.

The determination of shelf life involves scientific methods and testing to estimate how long a product will maintain its desired qualities under specified storage conditions. The shelf life can vary based on product type, ingredients, packaging, storage conditions, and handling practices.

Importance of Shelf Life Determination

1. Consumer Safety: Shelf life determination ensures that food products remain safe to eat and free from contamination or spoilage throughout their expected period of consumption.
2. Regulatory Compliance: Many regulatory authorities, such as the European Food Safety Authority (EFSA) and the U.S. Food and Drug Administration (FDA), require food manufacturers to establish and label the shelf life of products to meet food safety standards.
3. Quality Control: Determining shelf life helps manufacturers predict how long a product will maintain its quality, enabling better management of quality during production and storage.
4. Supply Chain Efficiency: Accurate shelf life determination allows for effective inventory control, reducing the risk of product waste due to spoilage or expiration and ensuring products are sold at their best quality.
5. Brand Reputation: Consistent product quality throughout its shelf life builds consumer trust and enhances brand reputation.

Factors Influencing Shelf Life

Several factors affect the shelf life of a food product, including:

1. Product Composition: Ingredients, preservatives, and the overall formulation of the product can impact its stability. High-moisture foods tend to have shorter shelf lives, while foods with preservatives can last longer.
2. Storage Conditions: Temperature, humidity, and light exposure during storage directly impact the rate of chemical, microbial, and physical changes that occur in the product.
3. Packaging: Packaging materials can either protect or accelerate the degradation of a product. Modified atmosphere packaging (MAP), vacuum sealing, and light-resistant packaging can extend shelf life by controlling oxygen, moisture, and light exposure.
4. Microbial Growth: Some foods are more susceptible to microbial growth (such as bacteria, moulds, or yeasts), which can spoil products. The rate of microbial contamination depends on the product’s stability – determined by characteristics such as water activity, pH level, and preservative content.
5. Oxidation: Oxidative reactions can alter the flavour, colour, and nutritional value of food products. Products with higher fat content are particularly susceptible to oxidation, which can lead to rancidity.
6. Environmental Factors: Temperature fluctuations, relative humidity, and exposure to oxygen, light, or contaminants can shorten a product’s shelf life.

Methods for Shelf Life Determination

1. Accelerated Shelf Life Testing (ASLT)
• Principle: This method involves subjecting the product to accelerated conditions (such as higher temperatures, increased humidity, and higher levels of oxygen) to speed up the deterioration processes. The results from ASLT are then used to predict the product’s shelf life under normal conditions.
• Use: Often used for products that are difficult to test for long periods under normal conditions, ASLT allows manufacturers to estimate the shelf life quickly.
• Limitations: The relationship between accelerated conditions and real-world storage conditions may not always be linear, meaning ASLT may not fully replicate the natural degradation process.
2. Real-Time Shelf Life Testing
• Principle: This is the most accurate method for determining shelf life, where the product is stored under normal conditions (e.g., recommended storage temperature) and tested over time for signs of spoilage or quality degradation.
• Use: It provides the most reliable data for shelf life, as it considers the product’s stability under the exact conditions it will experience in the supply chain and at the consumer’s home.
• Limitations: Real-time testing is time-consuming and costly, especially for products with long shelf lives.
3. Microbiological Testing
• Principle: This involves monitoring the growth of microorganisms in food products to assess the potential for spoilage or foodborne illness over time. Microbiological testing can include pathogen testing (e.g., Salmonella, E. coli) and total microbial counts.
• Use: This testing is particularly important for products with high moisture content or low acid, as these are more susceptible to microbial contamination.
• Limitations: Results are often specific to the storage conditions and do not always reflect the overall sensory quality of the product.
4. Sensory Evaluation
• Principle: Sensory testing involves the use of human panellists to evaluate the appearance, texture, taste, smell, and overall acceptability of a product over time.
• Use: Sensory evaluation is particularly useful for products where consumer acceptance is important. It helps to determine the point at which the product no longer meets the desired sensory qualities.
• Limitations: Sensory evaluation can be subjective, and panellist bias or variability in responses may impact the results.
5. Chemical Testing
• Principle: This involves testing for changes in the chemical composition of a product over time, such as measuring pH, fat oxidation (rancidity), moisture content, and acidity.
• Use: Chemical tests are particularly important for products prone to oxidation, such as oils, nuts, and dried fruits.
• Limitations: Chemical tests may not fully account for all quality aspects (e.g., sensory changes) and may require specialised equipment.

Determining Shelf Life through Statistical Modelling

Statistical models, such as Arrhenius models, can be used to predict the shelf life of food products based on data from accelerated shelf life tests or real-time testing. Statistical models incorporate factors like temperature and humidity to estimate the time it will take for certain quality attributes (e.g., microbial load, oxidation level) to reach unacceptable levels.

Labelling and Shelf Life Communication

Once the shelf life of a product is determined, it must be communicated clearly to consumers through proper labelling. Labels typically include:

• Best Before Date: Indicates when the product is expected to be at its best quality (e.g., taste, texture, appearance). This is common for products that are not at risk of causing harm after the date has passed but may degrade in quality.
• Use By Date: This is more common for perishable foods (e.g., meat, dairy) that must be consumed before the date to ensure safety. After this date, there could be an increased risk of foodborne illness.
• Storage Instructions: These are critical to ensure that consumers store the product in conditions that help maintain its safety and quality (e.g., “Keep refrigerated,” “Store in a cool, dry place”).
• Batch/Lot Numbers: These allow for traceability in case of recalls and enable the identification of products that may have exceeded their shelf life.

Conclusion

Accurately determining product shelf life is vital for food manufacturers to ensure product safety, quality, and regulatory compliance. By understanding the factors that influence shelf life and employing a combination of testing methods such as accelerated shelf life testing, real-time testing, and sensory evaluation, manufacturers can provide products that meet consumer expectations and reduce waste. Proper shelf life determination also supports effective product labelling, inventory management, and overall brand trust.

About The Food Industry Hub Knowledge Centre

The Food Industry Hub knowledge centre delivers informative content on a variety of topics pertinent to the food manufacturing industry.