The aim of this study was to evaluate the effect of illumination, packaging material and application of oxygen scavengers on the shelf life of two different cured cooked meat products in diverse retail storage conditions. For this purpose, ham luncheon sausage and pork liver pâté were packaged in high-and low-OTR (oxygen transmission rate) packages under modified atmosphere. Packages either did or did not contain a 50-ml O 2 capacity oxygen scavenger. Samples were stored at 7 C either in complete darkness or illuminated by fluorescent or LED lamps for the last 48 h of storage. Microbial quality of pâté was more crucial than that of ham sausage, partially due to a higher initial microbial load. Pâté was far more susceptible to discolouration and lipid oxidation than ham luncheon sausage. Illumination was a crucial aspect for discolouration of ham sausage, whereas pâté exhibited discolouration without illumination when packaged in low barrier packages. Hence, high barrier packages are indispensable for these types of products, especially pâté. Inclusion of an oxygen scavenger may lead to improved colour stability and lower lipid oxidation, provided that the packaging material had a sufficiently low OTR and some days of dark storage preceded illumination. Replacing a multilayered high-barrier packaging system with a lower barrier system with an added scavenger is not an interesting option as there is competition for oxygen absorption between the food product and the scavenger.

Alternative packaging concepts for two dry, shelf‐stable food products were evaluated. A trade‐off between recyclability (monolayer materials) and performance (multilayered high‐barrier materials) was made for the packaging materials. Caramellized cookies were packaged in flowpacks made of PP film (OTR 1307 cc/m2/d, WVTR 5 g/m2/d), acryl‐coated PVdC/PP film (OTR 21.8 cc/m2/d, WVTR 4.2 g/m2/d) as a reference material and metallized PP (MPP) film (OTR 31.2 cc/m2/d, WVTR 0.4 g/m2/d) and stored at 22°C and 50% relative humidity. Texture was compromised after 6 months of storage for the former two materials, while the latter provided an extension of textural acceptability. Whole milk powder was packaged in unsealed PE bags as a reference, representing a typical paper bag with a PE liner that is stapled shut without a seal. Alternative packages were sealed PE bags (OTR 1464 cc/m2/d, WVTR 3 g/m2/d), PE/PA/EVOH/PA/PE (OTR 0.25 cc/m2/d, WVTR 0.95 g/m2/d) and PA/EVOH/PA/PE (OTR 1.24 cc/m2/d, WVTR 8 g/m2/d) multilayer bags, and PP/Al/PE (OTR 0.1 cc/m2/d, WVTR 0.1 g/m2/d) bags and stored at room temperature and relative humidity between 70% and 90%. Unsealed bags were found to be unacceptable for storage at high humidity, due to excessive caking, discolouration and mould growth. Sealed PE bags provided adequate protection against moisture, yet not against oxygen ingress, leading to oxidative off‐odours. The barrier efficiency of PA/EVOH/PA/PE was compromised by the high humidity. Both PE/PA/EVOH/PA/PE and PP/Al/PE bags provided adequate protection for over a year.

No abstract

Since more and more pressure is exerted to reduce the use of plastic packaging materials, optimizing the use of food packaging is opportune. The aim of this study was to evaluate the combined effect of packaging materials, spanning a range of oxygen transmission rates (OTR), and retail illumination, on the microbial shelf life and safety of refrigerated ready‐to‐heat foods. Cooked potato slices were packaged in OPA/PP bags with a high OTR (28.85 ccO2/m2/d) and OPA‐EVOH/PP bags with a low OTR (6.57 ccO2/m2/d). Cooked composite meals were packaged in tray and foil combinations, also spanning a range of OTR: PP trays (2.09 ccO2/tray/d) with OPA/PP foils (28.85 ccO2/m2/d), PP trays with OPA‐EVOH/PP (6.57 ccO2/m2/d) foils, and PET trays (0.07 ccO2/tray/d) with PET top foil (32.86 ccO2/m2/d) . The packages were stored in a dark environment, or under fluorescent or LED light. Due to the rapid growth of lactic acid bacteria, the microbial shelf life of both food products was largely unaffected by the type of barrier. Illumination at 1000 lux for 12 hours per day led to temperature differences significantly affecting microbial growth. Based on the results, it could be concluded that re‐evaluating packaging material choices for these foods may prove valuable, since the use of high‐barrier multilayer packaging materials may be considered as a case of overpackaging.