Tomatoes

Research Results using Bluezone® Fresh Preservation Technology

Refrigerated Storage FFV Research Trials

Introduction

Tests of the anti-microbial performance of the Bluezone® Fresh Preservation Technology Model 2400 have been conducted in a packing shed where hydroponically grown tomatoes are packed and outbreaks of mould have been experienced leading to losses of product. 

The anti-microbial performance was evaluated by conducting before and after air sampling at several locations within the pack shed using standard bio-aerosol sampling procedures. Sample plates were then incubated and counts made of the resulting colony-forming units (CFUs). 

Equipment & protocol

The pack shed has dimensions of 45m x 35m and a ceiling height of 5.2m giving an air capacity of 8,190 cubic metres. Three Bluezone® Fresh Preservation Technology units were installed by placing these under conveyors and packing equipment. This was recognised as being fewer units than that recommended from earlier research by the manufacturer however there were only three units available at the time the trial was to commence. 

 A MicroBio MB1 Bioaerosol Sampler (http://www.cantiumscientific.com/MB1.html) was positioned inside the pack shed and connected to a vacuum pump. The sampling procedure was as follows: 

• Install a Potato Dextrose Agar (PDA) Petrie dish in the sampler and start the vacuum pump drawing 50 litre of air on to each dish. 
• Remove PSA dish from the sampler, put on the lid, tape the join and place in an incubator at 20°C for 72 hours. 
• After 72 hours, remove PSA dish and count the colony forming units (CFUs). 

Results

Examining these photos shows a clear reduction in number of CFUs with the Bluezone® in operation. 

Figure 1 – Sample plates before Bluezone® in operation

Figure 2 – Sample plates with Bluezone® in operation

Conclusion

Installation of the Bluezone® units in this environment has resulted in significant reduction of mould CFUs and retardation of their growth time, with quantitative reduction of at least 30% over the duration of the test.