How NIR Spectroscopy and Gas Analysis Can Improve Food Security  

Avoiding food loss and waste could be one way of fixing food security. According to new estimates, about 40% of food goes to waste, of which 50% is lost on farms. Of course, consumers have to tackle food waste, but food loss between farms and retailers needs to be collectively fixed by the food production industry. Accurate quality control and monitoring can be one of the approaches. Today, we discuss several ways in which precision gas analysis instrumentation (measuring CO2, O2, and C2H4) and NIR spectroscopy-based quality assessment tools can be used throughout the food supply chain to save food. 

Problems Leading to Food Loss 

Food loss amounts to 1.2 billion tonnes annually, according to new estimates released in 2021 by a joint study by WWF (World Wildlife Fund) and Tesco. Most losses, about 764 million tonnes, occur on farms, and 436 million tonnes of food loss occurs in the post-harvest stage, during transport, storage, manufacturing, and processing.  

There are several critical points in the food supply chain where precision tools can help: 

• More than half of vegetables are lost on the farm, where uneven ripening is one of the main reasons, besides harvest processes.  
• Post-harvest, wrong shape of produce, packaging, and storage conditions, lead to food loss. 
• At the retailers, confusion over packaging labels, “best before” dates, and “use before” dates cause customers to reject good food. 

Food Losses at the Farm  

NIR spectroscopy can reduce food losses at the farm due to uneven ripening and harvest damage and help in efficient sorting and grading to improve shelf-life. 

What is NIR Spectroscopy 

Near-infrared (NIR) spectroscopy is the interaction of the NIR band of light between 760–1400 nm with plant and animal tissue.  

Among all the light bands, NIR is ideal for use with organic or carbon-based compounds which constitute tissues because this band interacts with the hydrogen bonds formed with carbon (C-H), oxygen (O-H), and nitrogen (N-H). Depending on the compounds and their concentrations, the light is absorbed, reflected, or transmitted in varying amounts. Since each compound will also react with specific wavelengths of NIR light, it is possible to detect the identity of the compound and its levels in plant and animal tissue. 

NIR spectrometers, which measure these three interactions, are widely used to detect crucial compounds that influence the quality of plants and animals. NIR spectroscopy’s use is widespread for plants, especially for fresh produce. The following sections discuss how it can help the food industry achieve food security through quality control.   

 

Food loss in an apple orchard, Tasty misfits. (Image credits: https://medium.com/@Tastymisfits/food-waste-in-a-local-british-farm-eb2c2a85959f) 

Fixing Harvest Time 

It is difficult to determine the ripeness of fruits and vegetables based only on exterior color and firmness. Climacteric fruits, which need ethylene production to ripen, can reach harvest maturity and remain green and hard. Many of these fruits can be easily stored for weeks to months and artificially ripened later. When farmers wait too long to ensure their fresh produce is ready, they reduce the storage time. Harvesting fruits later when they are growing soft also increases bruising risks during harvest and storage. 

NIR-based quality meters can estimate internal physiology and quality parameters like dry matter (DM) content, soluble solids content (SSC), and acidity. For example, the Felix portable NIR Quality Meters can non-destructively estimate the levels of compounds precisely and rapidly to fix the right time to harvest. This can aid farmers in taking full advantage of their yield and extending storage time. 

The optimal DM percentage and Brix for SSC are established for each type of fruit and vegetable and the main varieties. For example, scientists recommend that mangoes are harvested when 90% of the crop reaches a DM of 14-16.5 percent. This ensures even ripening later that meets consumer taste preference, reducing rejection risks by retailers and suppliers.  

In the case of non-climacteric fruits, BRIX and internal color are essential for deciding harvest time. In addition, BRIX is useful for determining the ripeness of climacteric fruits later in the supply chain. 

Chemometric Analyses Help 

In all these cases, model building for chemometrics to analyze the complex spectral data is crucial in customizing a single tool, like the F-750 Produce Quality Meter, for specific fruits and their varieties. Or, because each parameter, like the optimal DM, will vary depending on varieties, region, soil, and cultivation methods, it is also possible to build models that are robust enough to handle a wide range of values for a fruit.   

This way a single commercial tool can be adapted as necessary. Often a company like Felix Instruments Applied Food Science will supply starter models and also provide support through initial training data. Connecting them to apps and field maps using the GPS further extends the value these tools can give to farmers. 

Sorting and Grading 

Portable tools like Felix NIR Quality Analyzers or online sensors can help quickly detect ripening and maturity stages in fresh produce to sort and grade them. This way, fresh produce of even quality is packed together, reducing ethylene-induced over-ripening or bruises. In addition, grading and sorting can prevent the rejection of goods by retailers as less mature, and ripe produce can be sold later. However, policy and social changes can only address the problem of so-called “ugly food” or wrong-shaped and sized fruits.  

Post-Harvest Stages 

Fresh produce, as well as animal and dairy products, can be sold fresh for consumption or get processed. Sorting can help segregate farm products based on freshness for processing, sales, or storage. 

Processing 

NIR quality meters can help food processors choose grains, oilseeds, fruits, vegetables, meat, fish, and milk for processing. NIR tools can be useful also for the authentication of sources of raw materials to avoid later rejection of products by retailers or suppliers. 

 Many processes continue to use portable, online, or inline NIR sensors to guide various processes by tracking the development of defining constituents. For example, in winemaking, beer-brewing, or olive oil extraction.   

NIR spectroscopy-based tools can once again help in grading finished goods based on signature composition, which is essential to meet strict regulations in international sales. For example, fat and water content in cheese. 

Storage and Ripening  

Fresh and processed food can be stored at room temperature or in cool, controlled atmosphere rooms.   

Handheld tools for ethylene, CO2, O2 analysis used for constant monitoring of the atmosphere in storage, simple or complex, can extend storage time and maintain the quality of fresh produce. 

If ethylene gas levels increase, the rooms should be scrubbed to prevent premature ripening. For example, monitoring ethylene levels can control respiration in potatoes to extend storage time with reduced power use for cooling. The oxygen and carbon dioxide levels will vary depending on the storage method and product type.  

Fixed tools, such as the Felix F-901 Accustore & Accuripe – Precision Atmosphere Control, will monitor, regulate and control the atmosphere, including scrubbing for ethylene. These tools are especially valuable in ripening rooms, where ethylene is introduced at controlled temperatures to ripen fruits and vegetables. 

Ethylene gas can also be used to detect the presence of certain fungal infections in thin-skinned fruits like tomatoes and grapes with gas analyzers. This can allow suppliers and retailers to cull spoiled food and protect the rest of the batch. 

Similarly, NIR spectroscopy-based tools can detect microbial spoilage that produces aflatoxins in rice and mycotoxins in maize. Regular checks followed by timely removal of spoilt portions can keep food safe and help to preserve staple grains.  

Packaging and Labeling 

Whether sold fresh or processed, foods are increasingly being packaged using innovative methods to protect the freshness of vegetables, fruits, fish, animal, and dairy products. Modified Atmosphere Packaging (MAP) uses targeted atmosphere mixtures to prevent microbial spoilage and odor development and increase shelf life.  

Each food product has an ideal storage atmosphere with defined ratios of oxygen, carbon dioxide, nitrogen, etc. These atmospheres are combined with suitable packaging material, emitters, and scavengers in active MAP to maintain modified atmospheres. In comparison, passive MAP uses the interaction of food with its atmosphere to reach the desired air mixture. 

In both these cases, regular checking of the enclosed atmosphere is necessary to look for gas leaks or changes in metabolites, as variations in temperature and length of storage can change the atmosphere. Gas analyzers like the Felix handheld headspace & MAP analyzer and the F-920 Check it! Gas Analyzer accurately measures oxygen and carbon dioxide precisely in real-time without damaging MAP’s integrity. This is a vital tool suppliers and retailers currently use to ensure their products have an appealing color, freshness, and quality to meet consumer preferences.  

The label “best before” date indicates quality, and food beyond this date is still safe to eat even though the quality is lower. The “use by” date is the date beyond which the package should be discarded. Consumers can get confused between the two labels and unnecessarily refuse food past “best before” dates.  

 Retailers can use gas analysis of headspace in packages and NIR spectroscopy quality estimates of available food to confirm that there is no microbial spoilage and that the food is safe. Raising awareness of this issue combined with discounts can overcome customers’ reluctance to pick up “best before” packages beyond the date. Such measures can potentially save food and increase retailers’ ROI. 

Waste Not, Want Not! 

Food loss is a global problem that occurs not just in developing countries but also in developed countries. Even countries in Europe and North America with heavily mechanized farm systems waste 58% of the global harvest. 

Meanwhile, the world must increase food production by 30%, whereas regions like South Asia and sub-Saharan Africa will have to double production by 2050. If there weren’t any food waste or loss, then many parts of the world would not have to worry about expanding food production. Therefore, besides quality control, numerous other technological, policy, and social solutions have to be in place to end food waste and loss to help achieve food security. 

Sources 

Johnson, L. K., Dunning, R. K., Bloom, J. D., Gunter, C. C., Boyette, M. D., and Creamer, N. G. (2018). Estimating on-farm food loss at the field level: a methodology and applied case study on a North Carolina farm. Resour. Conserv. Recy. 37, 243–250. DOI: 10.1016/j.resconrec.2018.05.017 

 

WWF. (July 21, 2021). Over 1 Billion Tonnes More Food Being Wasted Than Previously Estimated, Contributing 10% of All Greenhouse Gas Emissions. Retrieved from https://www.worldwildlife.org/press-releases/over-1-billion-tonnes-more-food-being-wasted-than-previously-estimated-contributing-10-of-all-greenhouse-gas-emissions 

 

UN. (February 4, 2022). UN Report: Food Systems “At Breaking Point.” https://populationmatters.org/news/2022/02/un-report-food-systems-breaking-point 

 

van Dijk, M., Morley, T., Rau, M.L. et al. (2021). A meta-analysis of projected global food demand and the population at risk of hunger for the period 2010–2050. Nat Food 2, 494–501. https://doi.org/10.1038/s43016-021-00322-9