New developments in controlled and modified atmosphere storage

The 13th International Controlled and Modified Atmosphere Research Conference (CAMA 2021) was held from 16 to 18 august 2021 to create a forum to discuss recent scientific and industrial developments of controlled and modified atmosphere technologies to fruit and vegetables. This online conference was organised under the aegis of ISHS and in collaboration with the EU RoxyCOST action. CAMA 2021 was attended by 176 attendees from 34 countries worldwide.? (D)CA and 1-MCPWhile the effect of (dynamic) controlled atmosphere storage and 1-MCP on extending storage life of different species and cultivars of fruit and vegetables is a recurring theme at conferences of the CAMA series, also new developments such as metal organic frameworks (MOFs) were introduced to bind ethylene and 1-MCP with the intent of evaluating their usefulness in regulating ethylene responses for packaged perishable produce. Dynamic controlled atmosphere techniques were also discussed, even in less common applications such as extending the storage life of cabbage. PhysiologyFruit that are stored under controlled and, to a lesser extent, modified atmosphere conditions may become hypoxic. Until now no much is known about the changes in the metabolism except that at some point there is a switch from respiration to fermentation that is associated with ethanol formulation causing off flavours and with the development of storage disorders. The discovery of biological oxygen sensors in model plants has also inspired postharvest physiologist to investigate whether such sensors are also active in apple fruit, and recent research has indeed shown that this is the case. It is conceivable that when this sensor detects low oxygen concentrations inside the fruit tissue an appropriate response would be fired to adapt the fruit to such conditions. This may explain why some fruit such as Conference pears need to be stored for three weeks prior to the application of CA. Such knowledge is very useful for the further development of dynamic controlled atmosphere technologies in particular in which sometimes oxygen levels as low as 0.2 kPa are reached. Several contributions addressed the molecular biology of oxygen signalling in pome fruit and changes in the respiratory metabolism during low oxygen storage. Interestingly, low oxygen storage may also be used to alleviate seemingly unrelated storage disorders such as chilling injury in tomato fruit. Sensors and methodsAroma development of fruit stored under CA, often in combination with the application of 1-MCP, has always been a concern, and even more so when DCA techniques are used. The use of novel techniques such as SIFT-MS,?Selected-ion flow-tube mass spectrometry, to monitor changes in the aroma of pome fruit during CA storage was illustrated during the conference. Aroma measurements can even be used in future DCA storage protocols to actively control the storage atmosphere. For this novel sensor principles such as multispecies gas tracing can be used. Other sensor techniques that were discussed focus on online respiration measurements and gas transport in fruit. Innovative optical techniques such as GAS-MAS can be used to measure oxygen profiles in intact fruit or vegetables. The gas diffusivity of fruit or vegetable tissue can be measured by means of X-ray CT, providing a means to estimate how fast oxygen diffuses within the fruit. Modified atmosphere packaging and minimally processed fruit and vegetablesCurrent trends of minimally processed fruit and vegetables are associated with lifestyle (food on the go, food available at any time and place, comfortable/convenient, ready-to-eat) and tailor-made products with high incentives for sustainability and local production. The need to re-evaluate the role of the packaging material was highlighted at the conference, especially in the light of the EU green deal that forces to minimize the use of packaging materials and to move towards more green, recyclable or compostable packaging materials.? The next CAMA conference will be organised in 2025 by Prof. Carolina Torres from Washington State University. ? On behalf of the KU Leuven organisation. More informationAnn Schenk, ann.schenk@vcbt.beMaarten Hertog,?maarten.hertog@kuleuven.be Pictures1 - Bart Nicolai, chair CAMA 20212 - Maarten Hertog, chair Organizing Committee3 - CAMA 2021 image, partial