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 Smart Food Distribution with Xsense
July 2009
According to Dr. Jean Pierre Emond of the UF/IFAS Center for Food Distribution and Retailing, University of Florida, the use of systems like Xsense that monitor temperature and humidity and transmit their data in real time is probably the most significant change in the produce industry in the last 20 years. Retailers can now implement First Expired First Out (FEFO) management, potentially saving millions of dollars annually.
Fresh perishables are a great challenge for retailers, they must be transported as fast as possible in order to provide consumers with the best quality goods. For some produce a delay of only a few hours in the cooling process or in the distribution chain can sufficiently reduce their marketability. Today, new knowledge and technologies allow for better control of the distribution chain from field and processing to the store.
Consumers rate supermarket by quality of fresh produce
For many retailers the best way to keep or to gain market share is by presenting an attractive produce section. A positive image of the produce department gives customers a better perception of the quality of the business. In the minds of many customers, if a store provides a high quality fresh produce section then they probably maintain the same high quality for other products in the store. The visible attributes of the produce are the most important factor when determining the market value of fresh fruit and vegetables. In an early study, consumers said the ripeness, freshness and taste of fruits and vegetables was the most important criteria (96%) for selecting an item while appearance and condition of the product was the second order of importance (94%). Although not visually perceptible, nutritional value was considered by about 66% of consumers to be the decisive factor for buying the product. However, the price retailers pay to keep the “image of freshness” is to have an inventory turnover of almost 50% per day. This is the highest percentage in a retail store followed by the meat and fish sections. One of the reasons is the perishable aspect of the produce. Most of the time, conditions found in the store are far from the recommended temperature and humidity needed to maintain optimal produce quality. Often, a short exposure of one or two hours to inadequate conditions (i.e. too high or too low temperatures, too dry or too moist) is enough to cause a dramatic drop in the visual quality of a produce.
Temperature is key
In fact, temperature is the element of the distribution environment that has the greatest impact on the storage life and safety of fresh perishables. Effective temperature management is the most important and simplest procedure for delaying product deterioration. For example, optimal temperature storage retards aging, softening, textural and color changes, as well as slowing undesirable metabolic changes and moisture loss, and inhibits pathogen invasion. Temperature is also the factor that can be easily and promptly controlled. Preservation of perishables quality and safety can only be achieved when the product is maintained under its optimal temperature as soon as possible after harvest or production. For sensitive products like strawberries and sweet corn that require low temperatures during handling, a short exposure to temperatures above 0ºC might reduce their normal shelf life from 2 weeks to 1 week or less.
Furthermore, University of Florida found in previous work that in many refrigerated displays, temperatures might vary between a minimum temperature of 3 to 8.5 ºC and a maximum temperature of 13.0 to 14.5ºC depending on the area inside of the display, even when the thermostat is set at 4ºC. Such temperature fluctuation is adequate for most fruits or vegetables sensitive to low temperature like tomatoes, cucumbers, mangoes or papayas since they all require a storage temperature of above 10ºC, but definitely not adequate for grapes, strawberries or lettuce which require a temperature of 0ºC. For example, one of the studies showed that the quality of broccoli stored at the wrong temperature was impaired after 2 to 6 hours and the broccoli was no longer acceptable for sale after that time. A small variation of 2ºC may reduce the “display life” of the produce by a factor of 2 or 3. Therefore, it seems obvious that even a small adjustment in the temperature setup (cold rooms and/or merchandising displays) may help to maintain the fresh appearance and nutritional value of fresh fruits and vegetables by at least three times. For example, a simple improvement made by our researchers in a refrigerated display layout reduced product losses for grapes by as much as 50%.
Humidity control important, too
Additionally, most fruits and vegetables contain more than 80% water, with some such as cucumbers, lettuce and melons containing about 95% water, which contribute to their turgid and crispy appearance. However, after harvesting, water lost by evaporation may be very fast, particularly in leafy vegetables such as spinach or lettuce. This leads to a rapid shriveling and wilting of the produce and turns the vegetable tissue into a tough, unattractive, and eventually inedible product. Thus, water loss results not only in appreciable weight loss but also in less attractive produce of poor texture and with lower quality. Moisture losses ranging from as little as 3% to 6% are enough to cause a noticeable loss of quality for many types of produce.
Needed: better understanding of cold chain distribution
Beside temperature and water loss, many other factors are known to be responsible for affecting in-store quality and safety. Among them are packaging, transportation, distribution center (DC) and store operations. Individually, these factors are not responsible for a total loss of quality, but a combination of a few of these parameters can produce significant losses. For example, initial quality requirements set the maximum level of quality the entire distribution process will have to maintain.
Understanding more about the entire distribution chain is important. Knowing in advance what it is happening is critical. Any systems that can communicate advanced information regarding shipment quality and safety aspects before it gets to the DC are essential from a quality assurance perspective. Currently, most digital temperature loggers have to be connected to a host device in order to download data, and because of this, they have limited ‘real-time’ data interactivity, and result in after-the-fact analysis for claims, quality analysis and related issues. RFID temperature loggers add wireless communication to read the temperature logger in real-time. The RFID tag, with associated hardware and software will add the benefit of having a pallet/tag scanned on receipt, so that if an alert (alert trigger programmable prior to shipping) is activated, the receiver knows immediately (not after-the-fact) that there is a potential problem with the shipment and can spend the time required on specific shipments rather than use random inspections.
For example, based on previous projects done by University of Florida, a better knowledge of the pre-cooling process for strawberries (implementing new requirements), as well as transit temperature monitoring can lead to rejection of one trailer load of quality-impaired strawberries per week at the DC. These strawberries would normally have been accepted at the DC, but under a more complete system of knowledge of the entire cold chain process the strawberries could be rejected. In this case a RFID temperature tag system was used to alarm the inspector of problematic pallets of strawberries. This can prevent a retailer from losing $11,126 per trailer/week per DC, which translates to $578,552 per year per DC. However, understanding the importance of better pre-cooling process as well as identifying weaknesses in the cold chain can result in $41,368 in profit per trailer/week per DC (loss from unsold strawberries due to waste: profits + price of the strawberries) which transforms into an annual profit of $2,151,136 per year per DC.
FEFO management becoming a reality
Today smart RFID systems that monitor temperature and humidity allow for the collection of information in “real time” that was not possible a few years ago. This is probably the most significant change in the produce industry in the last 20 years. The potential with these new systems is endless. Now it is possible for a fresh produce retailer to envision managing all his/her products using a “First Expired First Out (FEFO)” system rather than the traditional “First In First Out (FIFO).” Although, it is still a daily battle to convince retailers that their traditionally run operations based on “human intuition” cannot measure up with these new systems. The cost of these new systems may often be minor compared to the full benefit of using them in terms of waste reduction, quality consistency and customer satisfaction.
This is why University of Florida is teaming up with Xsense to demonstrate the benefits of smart RFID systems in the food retail industry. The Xsense system is the only commercial solution that can monitor temperature, humidity and GPS location from field to store. These parameters allow us to successfully integrate the FEFO system at any point on the distribution chain.
Jean-Pierre Emond, Ph.D., Professor and Co-Director,
UF/IFAS Center for Food Distribution and Retailing, University of Florida
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