Identification of acceptability limits for shelf life studies by integrating sensory and analytical data: the case study of packed almonds

Identifying acceptability limit is the essential condition for carrying out shelf life studies. Accurate quantification of the acceptability limit is a key factor to ensure a correct food dating while minimizing the risk of unnecessary food waste. In the case of shelf stable foods prone to oxidation, such as almonds, consumer sensory response constitutes a highly sensitive indicator to depict product quality decay during storage time. Accordingly, relevant acceptability limit is a sensory threshold. However, assessing consumer sensory acceptability requires complex and costly experimental designs, which are not feasible at industrial level for routine shelf life studies. In the present investigation, oxidation of packed almonds subjected to storage at 23, 35 and 45°C was assessed by monitoring the kinetics of peroxide values (PVs) and the corresponding evolution of consumer sensory rejection during storage times. The experimental findings evidenced a significant correlation (r > 0.98) between consumer sensory rejection and PV, irrespective of storage temperature. Demonstrated relationship between sensory rejection and PV makes it possible to turn a sensory threshold into analytical acceptability limits, expressed in PV. Using a simple quality indicator such as PV, for which the corresponding acceptability limit is based on consumer sensory response and is known, makes routine shelf life assessment activities carried out at industrial level in R&D and Quality Assurance frameworks easier and more cost-effective. Furthermore, the outcome substantiates the applicability of Accelerated Shelf Life Testing (ASLT) as a methodological approach to establish such correlations, thereby markedly reducing the time requirements for shelf life studies.