Reducing Food Waste with NIRS

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One way of increasing global food security is by reducing food loss throughout the supply chain. According to new estimates, about forty percent of food goes to waste, of which 50% is lost on farms. While consumers have some part to play in tackling food waste, farm and retail food loss must collectively be addressed by the food production industry. Accurate quality control and monitoring is an approach that has been proven effective.

Here, we discuss some ways that precision gas analysis and NIR spectroscopy instrumentation can be used throughout the food supply chain to lower the rate of waste.

Problems Leading to Food Loss

Food loss amounts to 1.2 billion tons annually, according to new estimates released in 2021 by a joint study by WWF (World Wildlife Fund) and Tesco. Most food loss, about 764 million tons, occurs on farms. 436 million tons 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 agriculture tools can help:

• More than half of vegetables are lost on the farm, where uneven ripening is one of the main causes, besides harvest processes.
• Post-harvest, poor packaging and incorrect storage conditions can lead to food loss. Often, misshapen, or “ugly,” produce is also discarded.
• At the retailers, confusion over package labeling, “best before” dates, and “use before” dates cause customers to reject good food.

Food Losses at the Farm

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

Why NIR Spectroscopy

Near-infrared (NIR) spectroscopy is based on 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. This band is ideal because it 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 individual compounds and their concentrations 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.

In the following sections we will address 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)

Determining Harvest Time

It is difficult to determine the ripeness of fruits and vegetables based on external color and firmness alone. Climacteric fruits, which need ethylene production to ripen, can reach harvest maturity while remaining 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 be certain their fresh produce is ready, they reduce the commodity’s possible 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 Instruments line of portable NIR Quality Analyzers can non-destructively estimate the levels of internal compounds precisely and rapidly to determine the right time to harvest. The ability to accurately gauge harvest time can aid farmers in taking full advantage of their yield and extending storage duration.

Optimal dry matter percentage and ºBrix (a measure of soluble sugars) are established not only for each type of fruit and vegetable but also for the main varieties within a single commodity. For example, scientists recommend that mangoes are harvested when 90% of the crop reaches a DM of 14-16.5 percent. This ensures that, even with later ripening, the fruits will meet consumer taste preferences, reducing rejection by retailers and suppliers.

In the case of non-climacteric fruits, ºBRIX and internal color are most important for deciding harvest time. 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 is used to analyze the complex spectral data collected by the spectrometer. This method is crucial for customizing a tool, like the F-750 Produce Quality Meter, for specific fruits and their unique varieties. Though the optimal level of each parameter, like DM, will vary depending on variety, region, soil, and cultivation methods, it is 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 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 in the rapid detection of ripening and maturity stages in fresh produce, to sort and grade them. This way, fresh produce of even quality are packed together, reducing ethylene-induced over-ripening, or bruising. Grading and sorting can prevent the rejection of goods by retailers, as less mature fruit can be held back and sold later.

Unfortunately, though proper monitoring and growing methods can help normalize a crop, the problem of so-called “ugly food” or wrong-shaped and sized fruits can ultimately only be dealt with by policy and social changes.

Post-Harvest Stages

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

Processing

NIR food quality meters can help processors in their choice of grains, oilseeds, fruits, vegetables, meat, fish, and milk for processing. NIR tools can also be for authentication of sources of raw materials to avoid later rejection 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 vital to meeting 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, and O2 analysis used for constant monitoring of the atmosphere in simple or complex storage can extend storage time and maintain fresh produce quality.

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 levels of oxygen and carbon dioxide will vary depending on the storage method and product type.

Fixed tools, such as the Felix F-901 AccuStore & AccuRipe – Precision Atmosphere Controllers, will monitor and regulate 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 tools can detect microbial spoilage that produces aflatoxin 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. Methods like Modified Atmosphere Packaging (MAP) use targeted atmosphere mixtures to prevent microbial spoilage and odor development, and increase shelf life.

Each kind of food product has an ideal storage atmosphere with defined ratios of oxygen, carbon dioxide, nitrogen, etc. In active MAP, these specified ratios are maintained by suitable packaging material, emitters, and scavengers. In contrast, passive MAP uses the interaction of food with its atmosphere to reach the desired air mixture.

In both these cases, regular assessment 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 measurement devices like the Felix handheld headspace & MAP analyzer, the F-920 Check It! Gas Analyzer precisely measure oxygen and carbon dioxide in real-time without damaging the integrity of MAP.

This vital tool is currently used by suppliers and retailers to ensure their products have an appealing color, freshness, and quality to meet consumer preferences.

Waste Not Want Not!

Food loss is a global problem that occurs in both developed and developing nations. Even in European and North American countries with heavily mechanized farm systems, food waste is as high as 58% of the global harvest.

At the same time, total global food production must increase by 30% and regions like South Asia and sub-Saharan Africa will have to double production by 2050 to keep up with population. With no waste, additional food production would essentially be a non-issue. While zeroing out waste entirely may not be feasible, even a modest reduction in food waste would significantly reduce or even eliminate the need for expanding food production in many regions of the world. Besides the use of quality control, numerous other technological, policy, and social solutions must be in place to end food waste and loss, and help in achieving 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