We all want it fresh

NATURAL product retailers are likely to have their roots in this larger world of food. In fact, shoppers’ desire for all things fresh – the most significant trend and force in food retailing today – has been gaining momentum for the past 20 years. Behind this fresh trend is the consumers’ strong and growing belief that fresh tastes better, creates a more interesting food experience and is more nutritious than anything in a box.

As a result, for food retailers all across the spectrum, from mini-marts and high-end specialty stores to conventional supermarkets, fresh has become the dominant strategy to increase foot traffic and attract a larger percentage of households.

Increasing pressures of a growing global competition is pushing the industry towards constant innovation to stay in the game. Improvements in processing and packaging technologies have facilitated the proliferation of high quality, innovative food products with fruit and vegetables as a major component. These include pickled vegetables like onions, kimchi and peppers, frozen dinners and entrées, pizzas, breakfast products, juices and soups.

Behind this fresh trend is the consumers’ strong and growing belief that fresh tastes better, creates a more interesting food experience and is more nutritious than anything in a box

“The fresh produce market is driven in large part by increased consumer demand and sophistication and corresponding adaptations by streamlined supply chains. These changes are accompanied by consolidation of retailers, an expansion of product offerings and movement towards year-round supply,” says Edwin Bontenbal, director of Market Development Food, Corbion Purac (www.corbion.com).

Safety in a bag

While the demand for fresher, healthier and safer convenience foods has stimulated sales of fresh-cut fruit and vegetables which are sold either direct to consumers or processed in products like salads and ready-to-eat meals, the nature and origin of fruit and vegetables make these products an excellent source of microbes, which can cause spoilage and food safety issues when further processed.

Nutrition labels on items in the produce section tend to be short. Unlike cereals, soups and sauces that come with long lists of ingredients on their packaging, an apple doesn’t need an ingredient list for consumers to know what they are buying (although it arrived at the supermarket shelf in a labeled package), and the ingredients for bagged salad are only as varied as the different lettuces in the bag. Many consumers just buy and start eating off the bag although the product may not be intended as “ready to eat” and food safety is not assured for this purpose.

Food manufacturers and processors need to take into account variables such as shelf life, discoloration, texture improvement and food safety, as well as consumer behavior on how the product is used, says Mr. Bontenbal.

They also need to consider which substance can safely deliver the desired effect, e.g. pathogen reduction or freshness preservation, without changing the quality or taste of the food, he adds.

Extending shelf life

As fresh fruit and vegetables come straight from nature, without any form of processing to extend shelf life, these products are very susceptible to spoilage. Spoilage is easily recognizable and is perceived by consumers as quality deterioration. An example is the browning of cut fruit.

Due to their origin, these products are also a great source of microbes, which cannot be eradicated through a processing step. These microbes can result in decreased shelf life, and even food safety issues. For strong or hard vegetables, such as carrots, peppers, harsher treatments can be used to kill the microorganisms. The characteristics of other can be changed by controlling the water activity (Aw) and pH, a method that has been used by food producers for centuries to extend the shelf life. Food products typically using this method include kimchi, sauerkraut, peppers, gherkins and olives. Lower water activities are used to assure that natural lactic acid fermentation will occur.

Traditionally, natural fermentation and/or vinegar have been used as an acidulant but the usage level is limited due to its resulting flavor impact. Corbion Purac’s products, for example, can be used to control the pH of the brine, allowing the processor to create a low pH environment while having a mild sour taste. The highly purified acids impart a mild sour taste, typical to the food while replacing a large part of the harsh vinegar, and can at the same time reduce the need for high salt levels (to lower the water activity).

Discoloration and spoilage

Everyone knows that sliced apples turn an unpleasant brown color very quickly due to enzymatic activity under the influence of oxygen, and even though they are nutritious and otherwise palatable, brown apple slices usually end up in the bin.

Fruit and vegetables have skins that provide natural protection against drying out, discoloration and other forms of spoilage. Cutting and peeling remove that natural protection, allowing deterioration and spoilage to begin. It is visible within minutes for foods like apples and bananas, but occurs without any outward sign for other fruit and vegetables.

“Without a thermal process, the enzyme activity cannot be stopped, and changing the pH or temperature can slow down the enzymatic reactions quite well. The use of organic acid combinations and ascorbic acid, or the use of mineral sources like ferrous gluconate, are common solutions to stabilize and maintain the color. However, not all acids or minerals are suitable since the flavor must not be compromised,” Mr. Bontenbal points out.

The company has developed specific lactic acid and derivative products that have proven to be successful in preventing discoloration while preserving the flavor of the product. These products are currently being used in many applications including apples, peppers, carrots, onions and black olives. For lettuce, more and different approaches are necessary to maintain the texture.

Food scientists have recently devised other practical ways to completely stop the brown discoloration of fruit like apple slices, and these methods put a new twist to an old idea of adding a protective coating to food. They rely on the addition of a thin edible surface film (carnauba wax from palm tree leaves) to the cut fruit, which delivers ingredients to arrest the apple discoloration process. The “coating” is applied to the surface of a food product. This protective layer helps preserve freshness, and also offers the advantage of being a suitable carrier for other food ingredients that can prevent browning and increase shelf life.

Decontaminating produce

The microbiological contamination of fresh produce has been associated with foodborne illness worldwide. In 2012, outbreaks of Norovirus in Germany were linked to the consumption of frozen strawberries from China, and in 2011, sprouted seeds were implicated in Escherichia coli outbreaks reported in Germany and France.

The current methods for washing and decontaminating produce, including commercial washing systems, cannot guarantee that pathogens, if present, will be removed. Chlorinated water is most commonly used to reduce bacterial counts while other additives such as ascorbic acid are used to inhibit enzymatic browning. There are also many other solutions being used such as combinations of hydrogen peroxide and/or organic acid blends of octanoic and peroxyacetic acid.

Despite the fact that known decontaminants do not require labeling as a processing aid, environmental legislative pressure is pushing the vegetable processing industry in Europe and the USA to look for alternatives to replace these products with more environmentally friendly solutions.

Researchers from Patras University (Greece) recently investigated the effect of two disinfection non-thermal treatments, UV light and Ultrasound (US) on bacterial decontamination and colour in fresh-cut lettuce and strawberry. They evaluated the efficacy of UV and US on the sanitation of inoculated lettuce and strawberry with a mix of E. coli, Listeria innocua, Salmonella enteritidis and Staphylococcus aureus.

Results showed that UV treatment on fresh-cut lettuce significantly reduced the populations of E. coli, L. innocua, S. enteritidis, and S. aureus by 1.75, 1.27, 1.39 e 1.21 log CFU/g, respectively. In addition, the populations of E. coli and S. Enteritidis were reduced by > 2 log CFU/g using US treatment. Significant reduction of all bacteria was reached after 20 minutes by UV light and after 30 minutes by US treatment.

In terms of overall appearance, firmness, and color, UV light and US treatment applied for a maximum exposure time of 45 minutes do not negatively affect the product quality. As UV light and ultrasound are non-thermal, safe, non-toxic, and environmental friendly technologies, the results suggest their application in the fresh cut industry as potential and effective alternatives to the traditional chemical sanitizers, such as chlorine and hydrogen peroxide, which are widely used in minimal processing. The next stage would be combining these treatments with acid/salt washes, especially if they allow for milder treatments (higher pH, lower T, higher water activity) while maintaining the treatment efficacy.

Improving texture

When selling fresh or preserved fruit and vegetables, quality deterioration can occur such as loss of firmness. Processors cannot make use of traditional processes to ensure the product has a sufficient shelf life, so they are forced to make use of alternative ways to ensure the quality of their products.

Loss of firmness of fruit and vegetables is mainly caused by deterioration of the cells or pectin structure. Use of cat ions, which are often a mineral source like calcium, can prevent this kind of quality loss by binding with the pectin structure. To allow the cation to react with the pectin, the source needs to be highly soluble. The main disadvantage of common mineral sources is that they are perceived to have an off-flavor and appear to be chemical like calcium chloride.

“Our highly soluble calcium lactate allows processors to firm their products like tomato, potato, gherkin, strawberries, etc. whether they’re sold as fresh or canned or whether they’re to be further processed (sliced and diced),” Mr. Bontenbal shares. The soluble calcium should be applied to the step in the process that loses the most structure, be it blanching or storage, he further elaborates.

Fresh food culture

Health-conscious consumers are gravitating more towards a fresh food culture, heavily influenced by celebrity chefs and reality cooking shows that emphasize fresh ingredients and home cooking. Produce markets and vertical farms in cities have grown explosively in the past 15 years to meet the demand. Online stores selling fresh produce are on the rise, from individual growers to larger collectives, and they are changing the way we shop. Apart from the convenience of having food home-delivered, it’s fresh, locally sourced and seasonal. Fresh is considered the ultimate, convenient, ready-to-eat solution.

Over the next decade as consumers seek additional fresh and nutritious foods, retailers will seek partnerships with processed food manufacturers and ingredient specialists to deliver fresh and convenient meal solutions. Revisiting traditional foods, produced according to traditional recipes but with new processes and quality standards will also satisfy the demand for healthy foods, with regional preference.

Mr. Bontenbal predicts, “These trends are pivotal and will define the food industry of the future. Bold, innovative and creative solutions will allow savvy food companies to step up to the table and meet the challenges of the fresh age.”