TIME‐TEMPERATURE INDICATOR TO MONITOR COLD CHAIN DISTRIBUTION OF FRESH SALMON (SALMO SALAR)

Abstract

This article summarizes the application and validation of a specific temperature‐time indicator (TTI) to monitor the shelf life of refrigerated salmon throughout its cold chain distribution. Reaction kinetics of the spoilage process was characterized by determining the kinetics for microbial population growth and chemical degradation (break down of nucleotides). The combined effect of these reactions on perceived organoleptic quality deterioration (appearance, odor, texture, gapping and color) was measured by a trained sensory panel. The TTI color change reaction from green to yellow was monitored with a colorimeter. The activation energies (Ea) for the spoilage reactions in the salmon and the TTI color change reaction were determined and compared for the required similarity. The color change reaction in the TTIs had Ea of 22–23 Kcal/mol, while the microbial growth and chemical degradation reactions were found to have Ea in the order of 17 and 15 Kcal/mol, respectively. Performance of the TTIs was tested under controlled constant and variable time‐temperature storage histories by comparing TTIs color change readings with sensory panel scores. Additionally, TTIs and data loggers were placed in a shipment of refrigerated salmon that traveled from Puerto Montt, Chile, to Gainesville, FL, U.S.A. via a combination of truck and air. Results showed that the TTIs used in this study with Ea of 22–23 Kcal/mol were capable of predicting the shelf life of refrigerated salmon within 10% error in cases of moderate temperature abuse (0–7C). However, TTIs with lower Ea closer to 18–19 Kcal/mol would be needed to accurately predict shelf life if product were to be subjected to more extreme temperature abuse with temperatures reaching 12–14C. PRACTICAL APPLICATIONS The list of products monitored by time‐temperature integrators or indicators (TTIs) has been steadily increasing, these include: fresh fruits and vegetables, fresh fish, flowers, frozen foods, dairy products, chocolates, photographic films, medical films, drugs and vaccines, cosmetics, beer, dog food, etc. TTIs can be used to monitor the distribution, and food and biological materials, and more diverse products. A tentative classification of the various applications of TTIs in food products would be: monitoring the distribution and storage; optimization of inventory management; shelf‐life prediction; and sanitary and quality prediction. Several studies have focused on the application of indicators for frozen and chilled foods. Our studies in the evaluation of chilled fish fillets have shown that indicators can be used satisfactorily to evaluate the quality of the product during distribution. The distribution of fish is one of the areas that had the greatest potential for implementation of the TTIs.

Process capability index Cpk for monitoring the thermal performance in the distribution of refrigerated products

“…A number of papers on refrigerated food transport address time-temperature evaluation along the cold chain process (Gigiel et al, 1998;Giannakourou et al, 2005;Estrada-Flores & Eddy, 2006;Pereira et al, 2010;Simpson et al, 2012). TTI data for such studies are usually gathered in field surveys (Pereira et al, 2010), in performance laboratory tests (Moureh & Derens, 2000;Tso et al, 2002;Estrada-Flores & Eddy, 2006;Jedermann et al, 2009), or with the help of computer based simulations (Gigiel et al, 1998;Food Refrigeration & Process Engineering Research Centre, 2000).…”

“…(James & James, 2010). But, since temperature largely determines the rate of microbial activity, which is the main cause of spoilage of most fresh food products (Borch & Arinder, 2002), continuous monitoring of the full time temperature history usually allows for an adequate control of the process along the short and medium distance distribution routes (Simpson et al, 2012;Flick et al, 2012). The quality of these products might change rapidly because they are submitted to a variety of risks during transport and storage that are responsible for material quality losses.…”

Intelligent Packaging and Food Safety

“…Critical prerequisites for the valid application of this approach are the systematic study and kinetic modelling of the temperature-dependent reactions that establish shelf-life criteria of the product as well as the response kinetics of the TTI (Simpson et al, 2012). When the food and the device become exposed to the same temperature-time history, the extent of reaction that occurred in the TTI can be related to the extent of reaction that occurred in the product and the integral effect of temperature can quantitatively be translated to food quality.…”

Evaluation on home storage performance of table grape based on sensory quality and consumers’ satisfaction

“…It has been widely adopted (e.g. Cyprian et al 2008;Simpson et al 2012) although it has lower accuracy than the physics and chemistry experiment in some aspects (Sipos et al 2011). For example, Mohapatra et al (2011) employed sensory approach to estimate the shelf life of fresh products.…”