Cold chain management in cut flower supply chains is now of major importance due to markets which are far apart. A research carried showed possible ways to realise the added value of investing in cut flower cold supply chains.

It suggests that in addition to the external quality parameters currently being used in the grading system at flower auctions, internal quality attributes such as vase life should be considered. It is assumed that considering internal quality attributes such as vase life will result in the realisation of the value of investing in cold chain management. Flowers from a well-managed cold chain are likely to have a longer vase life and also likely to attract higher prices. The use of predictive modelling to predict vase life and three predictive models that have been put forward in literature are discussed.

Temperature also has an effect on the rate of metabolism, water loss, tissue deterioration and growth of Botrytis cinerea in harvested cut flowers. Although the development of B. cinerea is mainly influenced by the presence of condensed water on the flower as it allows spores to germinate, temperature also play a role in the germination of the spores.

The presence of B. cinerea and other physiological defects seem to have great repercussions in the cut flower supply chain. A few or minor defects on the flowers can render them undesirable on the market for aesthetic reasons.


A minor quality remark by quality controllers at the auction floor can lead to a decrease in price of 5% to 10%. Therefore, cold chain management (CCM) is an important issue in the cut flower business. So what needs to be done for growers to realise the added value of investing in a cold supply chain as practising a strict cold chain comes along with a lot of costs to the grower. These costs should also translate into higher prices and more profit for the grower.

Cold chain management

CCM is defined as the process of planning, implementing and controlling efficient, effective flow and storage of perishable goods, related services and information from one or more points of origin to the points of production, distribution and consumption in order to meet customers’ requirements. Cold chain management is essential for preserving the harvested quality of cut flowers. Maintaining the cold chain is important for several reasons, all of which relate to maintaining product quality.

Effective CCM begins on the farm and ends once the product reaches the customer. Therefore, a cold chain is definitely a strategic competitive advantage in the floriculture business. CCM requires careful temperature control and quick reactions should be taken when anomalies appear in temperature or time delays occur. Temperature control at each stage of the supply chain is essential to maintain the required quality of a product until it reaches final consumer. Investment in CCM is therefore vital to cater for temperature abuse that often arises in the cold chain. Investment in CCM is therefore vital to cater for temperature abuse that often arises in the cold chain.


Temperature monitoring

Temperature has a significant influence on the development of physiological defects in many fresh produce, it is therefore of paramount importance to monitor timetemperature conditions in the chain and this information can be used to predict quality loss in the chain. Temperature monitoring and control is judged to be the solution to 90% of the quality problems, starting when the product is harvested on farm. Experiments show a dramatic reduction in vase life of cut flowers as storage temperature increases. In the experiments, the respiration of cut flowers increased exponentially as the temperature increased from 0°C to 20°C. The vase life of flowers of the ‘potomac pink’ cultivar stored dry at 0°C was 10.8 days longer than that of flowers stored at 7.5°C. The decrease in vase life of the flowers was matched by an exponential increase in the respiration of flowers at increasing storage temperatures. The experiments therefore demonstrated the importance of proper temperature control in the postharvest handling of cut flowers. In a detailed study of a wide range of cut flowers undertaken found that holding cut flowers at 7.2°C for five days reduced their vase life by an average of 30%.

The use of time-temperature indicators (TTIs) has helped growers to pin point problem areas in their supply chains. TTIs make it easy to identify temperature fluctuations in the cold chain. The importance of using TTIs to monitor temperature conditions in fresh produce supply chain. TTIs are effective in monitoring temperature hours in fresh produce supply chains. Information from TTIs can also be used to adjust and/ or improve management of temperature conditions in the cold supply chain and achieve required optimum temperatures. TTIs measure both time and temperature and integrate them into a single visible result and have the advantage of indicating the cumulative time-temperature history of the products.

The amount of rejected products in the distribution system can be minimised using a TTI-based monitoring system as it enables the classification of products according to keeping quality/shelf life remaining. TTIs have a great potential to satisfy the thermal monitoring requirements. Hence, the use of TTIs is of great importance in maintaining a good cold chain in cut flower supply chains.

A more advanced monitoring system through use of radio frequency identification (RFID) is also being used in monitoring temperature hours in agri-food supply chains.

The primary advantage of RFID is that it can facilitate the automated data collection without human intervention throughout the supply chain. Whilst use of TTIs to monitor temperature is a great step towards achieving optimum temperature conditions in the cut flower cold supply chain, there is need to be able to measure the added value of maintaining a strict cold supply chain. Information from TTIs gives signals to problem areas only. Hence, more work needs to be done to quantify the added value from maintaining a good cold supply chain in which optimum temperature of 2°C to 4°C is achieved. Temperature monitoring in itself is not an answer to high quality flowers or a longer vase life, but it is only a tool to alert the supply chain on problem areas that need attention.

For the added value of investing in CCM to be clearly visible, there is need for the development of models that enable prediction of vase life of flowers right from the moment of harvest to the pointof- consumption (customers). Also, it is important to develop an integrated system that allows virtually everyone involved in the supply chain to have access to the temperatures hours of each batch of flowers so as to improve the use of the data for decision-making.

Realising the value of investing into CCM Whilst growers benefit from maintaining a cold chain through improvement in quality and a longer vase life for their flowers, the auction system that is mostly used in the flower trading business, does not bring out the real value of maintaining a strict cold supply chain as the vase life of the flowers is not considered during the auction floor marketing system. Cut flowers are classified after harvest based on their external characteristics such as stem length, stage of maturity, flower size and foliage quality and internal quality of flowers which include vase life has not been incorporated into quality classification of flowers, especially at auction floors. This makes it difficult to realise the value of investing or managing a strict cold supply chain as expected vase life of a given batch is not considered.

For growers or any actor in a cold supply chain to appreciate the added value of maintaining a strict cold supply chain of 2°C to 4°C, tangible benefits realised out of maintaining such supply chain should be visible. The argument is that flowers out of a __2°C to 4°C cold supply chain should fetch better prices than those that were exposed to above optimum temperature. There is need for use of predictive models to estimate expected vase life of a given batch. Use of predictive models is likely to make it easy to relate CCM with benefits realised out of investing into such supply chains.

To be able to realise the value of maintaining a good or strict cold supply chain, there is need to relate information from data loggers on temperature hours flowers are exposed to in the chain and expected vase life. Tagging each batch with the expected vase life or with its temperature hours at the auction floors can help bring forth the value of maintaining a strict cold supply chain. The assumption is that with the help of predictive models that relate temperature hours and vase life, buyers at auction floors are likely to also consider vase life or temperature hours of a given batch in addition to the usual external quality aspects which are normally considered.

However, to be able to consider vase life at auctioning of flowers, there is need to have a systematic and universally acceptable predictive model of vase life in cut flowers so that buyers can easily translate temperature hours into remaining vase life.


Summary and conclusions

Based on this overview it can be concluded that for growers to realise the added value of maintaining a strict cold supply chain vase life of flowers in addition to external characteristics should also be considered at the auction floors. However, to be able to relate vase life and temperature hours, there is need for predictive models that can help estimate vase life of cut flowers. It is suggested that predictive models that can be easily used to relate temperature hours to vase life should be developed and used at auction floors to determine vase life.

Another simple and easy way that can help realise the added value of a cold supply chain is to make it compulsory for all growers to use data loggers to monitor temperature hours of their flowers from the moment of harvest. Allowing buyers to have access to time-temperature data from these data loggers will help buyers consider temperature hours the flowers had been exposed to in their buying decisions. It is therefore recommended that there should be unlimited access to information on temperature hours and there is also need to automate data into vase life model/ prediction. Doing so will help informed decision making in the cold supply chain and those who will have invested in a good cold chain are rewarded accordingly through better prices on their flowers.