Eva Almenar

Bio-based, breathable and antimicrobial packaging materials can affect in-package atmospheres and, consequently, the quality and safety of food products. Eva Almenar from the School of Packaging presents the materials’ challenges.

Deterioration in food is caused by physicochemical and microbiological changes since food products after harvest or slaughter are still active biological systems that interact with the environment (light, oxygen, moisture and others). This results in color, texture and flavor changes and, in some cases, can lead to toxicity of the food product.

Simple food packages provide a barrier to outside influences and protect the food from the environment (insects, dust, odors, light and others). Additional protection can be achieved by modifying the atmosphere inside the package. An adequate in-package atmosphere (including gases and vapors such as oxygen, carbon dioxide and water vapor) can extend food shelf-life, reduce food losses, improve food safety, open markets and increase options for consumers.

Currently, the most common technology used to modify the package headspace is active modified atmosphere packaging (AMAP): replacement of air with a single gas or mixture of gases that can slow down specific physicochemical and microbiological changes occurring as food deteriorates. However, limitations and deficiencies associated to AMAP (such as moisture control and residual oxygen) have led to the development of alternative packaging technologies. One current trend is the addition of specific additives to the package or packaging material that intentionally and dynamically change the amount of a target gas or vapor over time (such as moisture regulators and oxygen scavengers).

The packaging material is another factor that influences the in-package atmosphere, since the material permeability controls the exchange of gases and vapors between the package and the surrounding environment.

Although petrochemical-based materials dominate the food packaging market, environmental concerns over the use of these non-renewable and non-biodegradable packaging materials have led to a growing use of biodegradable alternatives originating from renewable sources. These materials tend to be more sensitive to environmental conditions than petrochemical-based materials because they are derived from biological systems and, consequently, they can more easily experience changes in permeability that result in undesired in-package atmospheres.

Therefore, the effects of the surrounding environment must be carefully examined and thoroughly understood when using these biodegradable alternatives originating from renewable sources to obtain atmospheres that can enhance food quality and safety.

Another type of packaging materials growing in use are “breathable” materials. Among these materials, microperforated films are used when high gas and/or vapor exchange through the package is required—as it is in the case of produce packaging. Changing the number, position, area and length of the microperforations allows the development of in-package atmospheres that match produce needs for shelf-life extension.

In the case of food products treated with an antimicrobial intervention prior to packaging, the type of antimicrobial intervention (such as chemical sanitizers) can modify the effect of the in-package atmosphere on quality and safety. Although new antimicrobial interventions are being used due to the increasing number of foodborne outbreaks, little is known about interactions between antimicrobial interventions and in-package gas compositions and their effect on the safety and quality of the food product. 

EDITOR’S NOTE: The research team led by Dr. Eva Almenar at the School of Packaging, Michigan State University, has been studying the effect of current packaging trends on in-package atmosphere and consequently, on the quality and safety of food products.

At Process Expo University at Process Expo 2015 (Chicago’s McCormick Place; Sept. 15-18), her presentation “Packaging Trends and Their Impact on In-Package Atmosphere: Effect on Food Quality and Safety” will cover how packaging trends affect in-package atmosphere including:

• the use of bio-based resins instead of petroleum-based ones;

• the interactions between antimicrobial interventions and in-package gas compositions;

• moisture regulators;

• microperforated films; and

• oxygen scavengers.

She will discuss the fundamental aspects of these packaging trends and their advantages and limitations. In addition, she’ll present examples of the effect of each of these packaging trends on the resulting quality and safety of food products.

All in all, this talk offers an opportunity for all stakeholders involved in the food packaging supply chain to get some insights into the effect of current packaging trends on in-package atmosphere and consequently, on the quality and safety of food products.

Eva Almenar received her Ph.D. in 2005 from the Institute of Agrochemistry and Food Technology-Spanish Council for Scientific Research (IATA-CSIC) for her work in active packaging. Since 2008, she has been an assistant professor at the School of Packaging at Michigan State University, and is working in the field of fresh produce packaging.