Eero Hurme

Active and smart packaging for meeting consumer demands for quality and safety

Over the past few decades, many new packaging techniques have been introduced in the quest for natural preservation of foods and on-time quality monitoring of packaged food to ensure good product quality and safety for the consumer. This paper discusses scientific, technological, commercial and legislative development, as well as consumer aspects and acceptance of the active and smart food packaging techniques with current or potential commercial value, and the elements that both the manufacturers of these packaging systems and the food industry should take into account before launching products using these techniques.

Leak indicators for modified-atmosphere packages

Package integrity is an essential requirement for the high quality of modified-atmosphere packaged (MAP) food. The most effective method of detecting a leakage non-destructively throughout the whole distribution chain from the manufacturer to the consumer is to use a visual leak indicator that is permanently attached to the package. This article reviews visual leak indicators that are based on the detection of oxygen and carbon dioxide. The limitations and benefits of the current indicator technologies are discussed. Commercial indicators and the problems associated with their adoption, as well as the safety aspects of indicators, are also introduced.

Myoglobin-based indicators for the evaluation of freshness of unmarinated broiler cuts

Abstract A principle for a novel intelligent packaging concept, which indicates specifically the spoilage or the lack of freshness of a food product, is described. This freshness indicator for modified atmosphere packed poultry meat is based on the indication of the presence of hydrogen sulphide (H2S), which is produced in considerable amounts during the ageing of packed poultry during storage. In the preliminary evaluation of the indicator principle promising results were obtained for H2S-sensitive indicators based on a visually detectable colour change of agarose immobilised myoglobin. The colour change of the indicators attached into the packages containing unmarinated broiler correlated with the microbiological and sensory quality of broiler samples and the onset of the colour change took place concurrently with the sensory rejection of the odour.

The effect of ethanol and oxygen absorption on the shelf‐life of packed sliced rye bread

The effect of ethanol emitters, 1% (v/v) ethanol-containing gases and oxygen absorbers on the shelf-life of whole grain rye bread was investigated in two 6 week storage experiments. The bread slices (215 g) were packed in 500 ml plastic containers with headspace volumes of 240 ml. The biggest ethanol emitters (2 and 3 G) extended the microbial shelf-life of rye bread from 8–12 to 26–27 days in the two experiments, and oxygen absorbers correspondingly to the end of the storage period (42 days). Small ethanol emitters (0.6 and 1 G) and 1% (v/v) ethanol-containing gases had no influence on the microbial shelf-life. Ethanol and oxygen absorbers had no effect on changes in texture and moisture during storage. The overall sensory quality of the samples without microbial growth was evaluated as rather good at the end of the storage period. The flavour of ethanol was discovered not to prevent the use of ethanol for the preservation of bread, since ethanol was detected only a few times in the panellist sensory evaluation

Effects of preparation procedures, packaging and storage on nutrient retention in peeled potatoes

The effects of preparation procedures and packaging on vitamin C, dietary fibre, sugars, ash and moisture contents were studied in prepeeled packaged potatoes during two cultivation seasons. The potato cultivars Bintje, Van Gogh and Nicola were studied. Potatoes of the Nicola cultivar had the highest initial vitamin C and sugar contents. Retention of nutrient contents in packaged, prepeeled potatoes was very good after a 7-day storage period. Vitamin C contents were higher in packaged potatoes than in fresh tubers when ascorbic acid was used in the washing solution but the levels decreased during the 7-day storage period. When calcium chloride was added as well into the washing solution vitamin C contents remained high throughout the storage period. These results show that it is possible to preserve the nutritional contents of packaged potatoes over a 7-day storage period. Cooking decreased vitamin C contents by about 30% and keeping the potatoes hot for 1 h after cooking decreased vitamin C contents a further 10%.

Shelf life of sliced raw potatoes of various cultivar varieties--substitution of bisulfites.

The effects of potato variety (Van Gogh, Bintje and Fambo), washing with browning prevention chemicals in place of sodium bisulfite, percentages of CO2, O2, and N2 in the package headspace, and storage time (1, 4, and 7 days) on the sensory and microbiological quality of potato slices were examined. Citric acid and ascorbic acid (at 0.1% each and at 0.5% each) were used as browning prevention chemicals. In the packaging atmosphere the percentage of N2 was 75 or 80%, the percentage of O2 was 5 or 0%, and the percentage of CO2 was 20% at the beginning of storage. Packed potato slices were stored in the dark at 5 degrees C. Darkening was the most important factor limiting the sensory quality of raw potato slices. Darkening occurred quickly with Fambo slices; it seems that Fambo is not a suitable potato variety if slices are to be stored. Water-washed and cooked Van Gogh slices were still acceptable for retailing after a storage period of 7 days. After 7 days of storage the best sensory quality of both raw and cooked Bintje slices was obtained with washing solutions containing 0.1 to 0.5% citric and ascorbic acids and with the gas mixture containing 20% CO2 and 80% N2. The number of microorganisms was higher in samples stored in the atmosphere containing 5% O2 than samples stored in the atmosphere containing 0% O2. Washing of potato slices with browning prevention chemicals decreased the number of microorganisms compared to potato slices not washed or potato slices washed with water after 7 days of storage.

Detection of improper sealing and quality deterioration of modified-atmosphere-packed pizza by a colour indicator

Abstract The effects of leaking on the quality of modified-atmosphere-packed chilled minced meat pizza were studied. Capillary-like leaks of various sizes were made experimentally in the sealing area with tungsten threads of diameters 50 and 100 μm. Test packages were stored for 5 weeks at 5 °C (in darkness or under illumination) or at 10 °C in darkness and the microbial and sensory deterioration of pizzas packed in leaking packages was compared to that occurring in intact packages. The diameter of the capillary leakage was found to influence markedly the rate of deterioration of pizzas stored under all conditions. The higher storage temperature accelerated the deterioration of the quality of pizzas in all packages, but illumination increased the rate of deterioration especially in leaking packages. The colour indicator tested reacted to different leak sizes as anticipated and was shown to be reliable in leak detection.

Shelf-life of prepeeled potato cultivated, stored, and processed by various methods.

The effects of cultivation conditions, winter storage, peeling method, browning prevention chemicals replacing sodium bisulfite, and packing methods on the sensory, nutritional and microbiological quality of pre-peeled potato were examined. Two different cultivation lots of the potato variety Van Gogh were used. Cultivation and harvesting conditions and peeling method were the most important facts reducing the sensory quality, especially the appearance, of prepeeled and sliced potatoes. Cooking and baking of potatoes decreased the appearance defects detected in raw potatoes. The levels of vitamin C in packaged samples decreased during winter storage. Cooking for 10 min and keeping potatoes at 60 degrees C for 1 h after cooking also decreased the content of vitamin C. In potato samples immediately after treatments aerobic bacteria were present at levels of 400 to 2,950 CFU/g and lactic acid bacteria at levels of 8 to 16 CFU/g. The number of aerobic bacteria did not increase during storage, and the number of lactic acid bacteria increased at the most to 90 CFU/g. Peeling, washing and packaging methods, cultivation conditions, and winter storage did not have important effects on the number of microbes present.

The effect of package leakage on the shelf-life of modified atmosphere packed minced meat steaks and its detection

The effect of leaking on the quality and leak detection in modified atmosphere packages of chilled minced meat steaks were studied. Leaks of various sizes were made experimentally with tungsten thread and packages were stored for 5 weeks at +5°C or +10°C. The results indicated that the microbial counts in minced meat steaks increased with increasing leak size at the storage temperature of +5°C, but not at +10°C, where temperature became a more important factor for microbial growth than the rate of the leakage studied. At both temperatures, the sensory quality of minced meat steaks was better maintained in packages with capillary leaks the diameter and length of which were 69 and 3000 μm and 169 μm and 3000 μm, respectively, than in intact packages or in packages with capillary or pinhole leaks the diameter and length of which were 270 and 3000 μm or 65 and 70 μm, respectively. The packages stored at +10°C contained a coloured redox indicator, which was very useful and reliable in the monitoring of those leaking packages which were poor in quality.

Penetration of bacteria through microholes in semirigid aseptic and retort packages

The penetration of vegetative cells of Enterobacter aerogenes , Bacillus subtilis , Micrococcus varians , and Leuconostoc mesenteraides through laser-drilled holes of diameter 10 to 20 μm in the lid of commercially manufactured semirigid aseptic cups filled with milk chocolate pudding and retort trays filled with spaghetti in meat sauce (only E. aerogenes ) was studied. The ability of bacteria to pass via leakages was determined using an immersion biotest method. The threshold leakage diameter determined for both products tested was about 10 μm. The contamination rate of leaking packages was much higher for aseptic cups than retort trays. The results indicated that the factors increasing the rate of bacterial penetration into test packages are large hole size, small hole length, small bacteria diameter and leakage channels filled with liquid instead of dried foodstuff and/or bacterial suspension. The results are useful as a guideline for the requirements of on-line, nondestructive, package-integrity testers for testing packages.