Nathalie Gontard, from INRA in France, focused on the development of biodegradable engineered materials for food packaging as part of the recently-finished EU project EcoBioCAP.
Kay Cooksey of Clemson University described the challenges when developing an antimicrobial food packaging film from lab bench top to a continuous converting process.
Prof Dr Rudi F. Vogel said Lactococcus (L.) piscium strains may be considered as protective or ripening cultures for MAP meat as they supressed the growth of other bacteria.
Active and Intelligent packaging strand
Researchers named above and others presented their work at the Innovations in Food Packaging, Shelf Life and Food Safety conference in Erding, Germany.
Elsevier and Fraunhofer Institute for Process Engineering and Packaging IVV co-organised the conference. Food Packaging and Shelf Life is an Elsevier journal.
Gonthard said in EcoBioCAP packaging was developed using composite structures based on constituents (biopolyesters, fibres, proteins, polyphenolic compounds, bio-adhesives and high-performance bio-additives) from food industry (oil, dairy, cereal and beer) by-products.
Processing strategies (blends and multilayers at different scales) enabled customisation of the packaging’s properties to fit functional, cost, safety and environmental impact requirements of the targeted fresh food (fruit and vegetables, cheese and ready-to-eat meals).
The polymer of choice was poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) and wheat straw fibres were the food industry by-product.
Three multi-scale modelling approaches were developed in the project: material engineering – looking at the molecular, nano, micro-composite level, process engineering to adapt packaging to the food requirements and knowledge engineering which includes industrial constraints, consumer needs and environmental impact.
From lab to commercial production
Cooksey said the target application for antimicrobial packaging has been pathogenic bacteria and spoilage microorganisms present on ready-to-eat foods from post-process operations.
She said a current method incorporates nisin as an antimicrobial into a coating for continuous production equipment adding it was important to ensure what is being used as a barrier layer doesn’t cause the antimicrobial to go away from food.
Previous methods include solution, cast coating, draw downs, encapsulation, heat press, compounding and extrusion. Carriers for nisin have included methyl cellulose, pectin, chitosan, corn zein and blends.
Problems with these include heat seal strength, delamination and inability to adapt to a continuous process. Batch control, drying time, blocking and heat sealing have been addressed through formulation adjustments, according to the study.
Cooksey said the big issue around small batches to continuous production was around formulation changes during scale up and differing equipment requirements.
She also raised questions such as when does the antimicrobial become active, what pathogens is it effective against, what log reduction is significant and what food storage temperature conditions is the product exposed to.
Microbial growth on meat
Dr Vogel used said his team used MALDI-TOF MS analysis to differentiate isolates by low molecular weight sub-proteome patterns below species level to provide insight into emerging spoilage microbiota in MAP white (chicken) and red (beef) meats.
Factors for microbiota in MAP include carbon dioxide and oxygen content, temperature, meat type and initial microbial contamination.
L. piscium do not produce off odours, but give MAP stored meats ‘ripened’ impression, according to the study.
As deliberately inoculated L. piscium strains supressed growth of other bacteria, they may be considered as protective or ripening cultures for MAP meat.