Time temperature indicators as devices intelligent packaging

PAVELKOVA ADRIANA: Time temperature indicators as devices intelligent packaging. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 1, pp. 245–251 Food packaging is an important part of food production. Temperature is a one of crucial factor which aff ecting the quality and safety of food products during distribution, transport and storage. The one way of control of food quality and safety is the application of new packaging systems, which also include the intelligent or smart packaging. Intelligent packaging is a packaging system using diff erent indicators for monitoring the conditions of production, but in particular the conditions during transport and storage. Among these indicators include the time-temperature indicators to monitor changes in temperature, which is exposed the product and to inform consumers about the potential risks associated with consumption of these products. Time temperature indicators are devices that show an irreversible change in a physical characteristic, usually color or shape, in response to temperature history. Some are designed to monitor the evolution of temperature with time along the distribution chain and others are designed to be used in the consumer packages. packaging, intelligent packaging, time temperature indicator, food quality Food is packaged for storage, preservation, and protection traditionally for a long time. These three are the basis functions of food packaging that are still required today for better maintenance of quality and handling of foods (Galic et al., 2011). A modern quality and safety assurance system should prevent contamination through the monitoring, recording, and controlling of critical parameters during a product’s entire life cycle, which includes the post processing phase and extends over the time of use by the fi nal consumer (Koutsoumanis et al., 2005). An important indicator for monitoring the quality of packaged food is temperature. Time/ temperature indicators or integrators (TTIs) are used as cost-eff ective and user-friendly devices to monitor, record, and translate the overall eff ect of temperature history on food quality in the chill chain down to a product unit level (Taoukis, 2001; Taoukis, Labuza, 2003; Giannakourou et al., 2005). Depending on the working principle, TTI systems are classifi ed as chemical, physicochemical, or biological systems, with their integrated time-/ temperature-dependent change being manifested as an irreversible visible color development, a movement toward a color change, or a mechanical change in consistency. The indicators can give information about the product quality directly, the package and its headspace gases and the storage conditions of the package (Gestrelius et al., 1994; Smolander et al., 1997; Ahvenainen, Hurme, 1997; Ahvenainen et al., 1998; Ohlsson, Bengtsson, 2002; Coles, Kirwan, 2011). In this article, we focus on aspects of intelligent packaging concepts, which provide information on the quality and safety of food products packed by the time-temperature indicators. Smart packaging concept Intelligent packaging (also described as smart packaging) is packaging that in some way senses some of the properties of the food it encloses or the environment in which it is kept and is able to inform the manufacturer, retailer, and consumer of the state of these properties. Although distinctly diff erent from the concept of active packaging, intelligent packaging can be used to check the eff ectiveness and integrity of the active packaging systems (Hutton, 2003). Yam et al. (2005) describe 246 Adriana Pavelkova a package is “intelligent” if it has the ability to track the product, sense the environment inside or outside the package, and communicate with the consumer. For example, an intelligent package is one that can monitor the quality/safety condition of a food product and provide early warning to the consumer or food manufacturer. Intelligent packaging refers to a package that can sense environmental changes, and in turn informs the changes to the users (Summers, 1992). Rodrigues and Han (2003) defi ned intelligent packaging as having two categories: simple intelligent packaging (as defi ned by Summers, 1992), and interactive or responsive intelligent packaging. In thelater, the packaging contains sensors that notify consumers that the product is impaired, and they may begin to undo the harmful changes that have occurred in the food product (Karel, 2000; Rodrigues, Han, 2003). Such packaging systems contain devices that are capable of sensing and providing information about the functions and properties of the packaged foods (Han et al., 2005), and/or contain an external or internal indicator for the active product history and quality determination (Ohlsson, Bengtsson, 2002). These types of devices can be divided into three groups. 1. The external indicators, which are attached outside the package, and include time temperature indicators and physical shock indicators. 2. The internal indicators, which are placed inside the package placed in the headspace of the package or attached to the lid – for example, oxygen leak indicators, microbial indicators (Ahvenainen, 2003). 3. The indicators that increase the effi ciency of information fl ow and eff ective communication between the product and the consumer, for example special bar codes that store food product information such as use, and consumption date expiration. Product traceability, anti-the , anticounterfeiting, and tamperproof devices are also included in this category (Coles et al., 2003). Intelligent packaging could be defi ned; as a packaging system that is capable of carrying out intelligent functions (such as sensing, detecting, tracing, recording and communicating) to facilitate decision making to extend shelf life, improve quality, enhance safety, provide information, and warn about possible problems (Otles, Yalcin, 2008). Examples of external and internal indicators and their working principles used in intelligent packaging are showed in Tab. I. While active packaging incorporates robust ways to control oxidation, microbial growth, and moisture, smart packaging designs facilitate the monitoring of food quality (Kerry et al., 2006). TTIs, ripeness indicators, chemical sensors, biosensors and RFID are all examples of components in smart packaging. Most of these smart devices have not had widespread commercial application. For example TTIs can play a critical role in indicating the freshness and safety of a food product. They monitor and communicate which food products are safe to consume, and which are not. This becomes extremely important when food is stored in less than optimal conditions such as extreme heat or freezing. In the case of foods that should not be frozen, a TTI would indicate whether the food had been improperly exposed to cold temperatures. Conversely, a TTI could specify whether foods sensitive to heat had been exposed to unnaturally high temperatures and the duration of exposure (Kuswandi et al., 2011). Principle of intelligent packaging In packaging, “smartness” can have many meanings, and covers a number of functionalities, depending on the product being packaged – food, beverage, pharmaceutical, household products etc. Examples of current and future functions that are considered to have “smartness” would be packages that: 1. Retain the integrity and actively prevent food spoilage (extend shelf life). 2. Enhance product attributes (look, taste, fl avour,