B. De Meulenaer

Active and intelligent packaging: applications and regulatory aspects

Changes in the way foods are produced, distributed, stored and retailed, reflecting the continuing increase in consumer demands for improved quality and extended shelf-life for packaged foods, are placing ever-greater demands on the performance of food packaging. Consumers want to be assured that the packaging is fulfilling its function of protecting the integrity, quality, freshness and safety of foods. To provide this assurance and help improve the performance of the packaging, innovative active and intelligent packaging concepts are being developed and applied in various countries. In Europe, however, the development and application of active and intelligent packaging systems have been limited thus far. The main reasons are legislative restrictions and a lack of knowledge about consumer acceptance, the efficacy of such systems, and the economic and environmental impact they may have. Therefore, in 1999, a European study was started within the framework of the EU FAIR R&D programme. It aims to initiate amendments to European legislation for food-contact materials to establish and implement active and intelligent systems within the current relevant regulations for packaged food in Europe. This paper presents an overview of existing active and intelligent systems and their current and future food-related applications. In addition, developments and trends in active and intelligent food packaging are discussed. The objectives and the work programme of the European project are reviewed and the results obtained so far are presented. The benefits for both the European consumer and the European food and food-packaging industries are highlighted.

Co-occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania.

This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 µg kg−1 (median = 363 µg kg−1) and in 15% exceeded 1000 µg kg−1; the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 µg kg−1 (median = 24 µg kg−1). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 µg kg−1). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies.

Optimization and evaluation of a decontamination step with peroxyacetic acid for fresh-cut produce.

Since several disadvantages are associated with the use of sodium hypochlorite as a decontamination agent, the attention for alternative agents such as peroxyacetic acid (PAA) is increasing. In this study the effectiveness of PAA to remove the native microflora was tested in four types of fresh-cut vegetables: grated carrots, fresh-cut white cabbage, iceberg lettuce and leek. Furthermore, the influence of varying PAA concentrations (0, 25, 80, 150 and 250 ppm) and varying contact times (1, 5 and 10 min) was described by means of a linear model. The efficiency of PAA to remove the native flora was highly dependent on the type of fresh-cut produce: the highest microbial reductions were obtained for carrots (0.5-3.5 log cfu/g) and white cabbage (0.5-3.5 log cfu/g) followed by iceberg lettuce (0.4-2.4 log cfu/g). The obtained efficiency was the lowest for fresh-cut leek (0.4-1.4 log cfu/g). Furthermore, all the treated samples, regardless of the type of vegetable and the contact time and concentration of the PAA treatment, were acceptable for consumption.

Effects of food composition on the inactivation of foodborne microorganisms by chlorine dioxide.

Chlorine dioxide (ClO2) is a strong oxidizing agent that can be applied in solution as well as in the gaseous state. It has bactericidal, fungicidal and viricidal properties. Several food-related microorganisms, including Gram-negative and Gram-positive bacteria, yeasts, mould spores and Bacillus cereus spores were tested for their susceptibility to 0.08 mg/L gaseous ClO2 during 1 min at a relative humidity of 90%. In this screening, the resistance of the different groups of microorganisms towards gaseous ClO2 generally increased in the order Gram-negative bacteria, Gram-positive bacteria, yeasts and mould spores and Bacillus cereus spores. With this treatment, reductions of microbial numbers between 0.1 and 3.5 log cfu/cm2 could be achieved. The effects of the food components starch, fat, protein and NaCl on the antimicrobial activity of gaseous ClO2 were also evaluated. Soluble starch, corn oil, butter, whey protein isolate and NaCl were added in incremental concentrations to portions of an agar medium. Then, plates of the supplemented agars were inoculated with Leuconostoc mesenteroïdes at numbers of 4 log cfu/cm2 and subsequently treated with ClO2. Both soluble starch and NaCl did not have an effect on the antimicrobial efficiency of ClO2. However, butter, corn oil or whey protein in the agar almost eliminated the antimicrobial effect of ClO2. In corn oil-water emulsions treated with gaseous ClO2 the peroxide value increased significantly, indicating the formation of primary oxidation products. Similarly, a treatment with ClO2 increased the protein carbonyl content and induced the transformation of SH-groups to -S-S-groups in whey protein. The findings suggest that gaseous ClO2 will be a highly effective decontaminating agent for carbohydrate-rich foods, but that it would be less effective for the decontamination of high-protein and fatty foods.

ELISA detection of hazelnut proteins: effect of protein glycation in the presence or absence of wheat proteins

Hazelnuts are widely used in the food industry, especially confectionary foods. Nevertheless, these nuts contain several allergenic proteins that may be unexpectedly present as contaminants in various foods and may pose a serious threat to allergic consumers. The enzyme-linked immunosorbent assay (ELISA) is the preferred method to assess the level of hazelnut protein contamination. It is commonly used by both the food industry and enforcement agencies. Several ELISA kits are commercially available. However, protein detectability by ELISA may be affected by severe changes that proteins undergo during processing. The aim of this study is therefore to investigate the impact of processing on the ability to detect hazelnut protein by four commercial ELISA kits. Hazelnut proteins in the presence or absence of soluble wheat proteins were modified with glucose via the Maillard reaction. Changes in hazelnut proteins, such as the formation of protein-bound carbonyls, losses of reactive lysine residues and free amino groups, and severe aggregation dramatically affected the hazelnut protein detection by the commercial kits. The observed impact was highly dependent on the type of ELISA kit used.

Influence of polymer matrix and adsorption onto silica materials on the migration of α-tocopherol into 95% ethanol from active packaging

In this study, the effect of polymer materials with different polarity, namely low density polyethylene (LDPE) and ethylene vinyl acetate (EVA), on the migration behaviour of α-tocopherol from active packaging was investigated. The antioxidant was also adsorbed onto silica materials, namely SBA-15 (Santa Barbara-15) and Syloblock, in order to protect the antioxidant during extrusion and to ensure a controlled and sufficient release during the shelf-life of the food product. Migration experiments were performed at 7.0 ± 0.5°C and 95% ethanol was used as fatty food simulant. All films contained a high concentration of α-tocopherol, ∼ 2000 mg kg−1, to obtain an active packaging. Polymer matrix had a small influence on the migration profile. The migration of 80% of total migrated amount of antioxidant was retarded for 2.4 days by using LDPE instead of EVA. When α-tocopherol was adsorbed onto both silica materials, the migration of 80% of total migrated amount of antioxidant was retarded for 3.4 days in comparison to pure α-tocopherol. No difference was seen between the migration profiles of α-tocopherol adsorbed onto both silica materials. In the case of pure α-tocopherol, 82% of the initial amount of α-tocopherol in the film migrated into the food simulant at a rather fast migration rate. In the case of adsorption on silica materials, a total migration was observed. These antioxidative films can have positive food applications.

Assessment of the acrylamide intake of the Belgian population and the effect of mitigation strategies.

The acrylamide (AA) intake of the Belgian consumer was calculated based on AA monitoring data of the Belgian Federal Agency for the Safety of the Food Chain (FASFC) and consumption data of the Belgian food consumption survey coordinated by the Scientific Institute for Public Health (3214 participants of 15 years or older). The average AA exposure, calculated probabilistically, was 0.4 µg kg−1 body weight (bw) day−1 (P97.5 = 1.6 µg kg−1 bw day−1), the main contributors to the average intake being chips (23%), coffee (19%), biscuits (13%), and bread (12%). Additionally, the impact of a number of AA mitigation scenarios was evaluated (German minimization concept, scenarios for mitigation from the literature, signal values), which is an important issue for public health as well as for policy-makers. Specific actions in cooperation with the food industry to reduce the AA content of foods seems to be a more efficient strategy than mere implementation of signal values. Considering that an important share of the AA intake is due to prepared meals, the catering industry as well as consumers need to be better informed on the various possibilities for keeping the AA content of meals as low as possible.

Effect of protein glycation in the presence or absence of wheat proteins on detection of soybean proteins by commercial ELISA

Soybean (Glycine max) is the worlds primary provider of protein and oil and is widely used in foodstuffs. However, the use of soybean in foodstuffs might pose a serious threat to allergic consumers since some proteins can cause allergic reactions. To date mostly ELISA methods are used for testing contamination of foodstuffs with soybean. In view of the complexity regarding allergen detection in foodstuffs and appropriate food product labelling, the aim of this study was to investigate the impact of the Maillard reaction on the detectability of soybean proteins using commercial ELISA kits. Accumulation of protein-bound carbonyls, modification of reactive lysine residues and severe aggregation as a result of incubation with glucose, in the presence or absence of soluble wheat proteins, were recorded. Moreover, detection of soybean proteins by means of three commercial ELISA kits was strongly altered and was highly dependent on the type of kit used.

Fumonisins exposure from freshly harvested and stored maize and its relationship with traditional agronomic practices in Rombo district, Tanzania

The exposure to fumonisins from the maize harvest of 2006 (before and after sorting and storage) for 67 families was assessed along with its statistical association with agronomic practices in Rombo, Tanzania. Fumonisins were determined by high-performance liquid chromatography (HPLC) and exposure estimated based on 60 kg body weight and maize intake of 356 g per person day−1. Based on contamination in the unsorted maize, exposure for 27% of the families would exceed the provisional maximum tolerable daily intake of 2 µg kg−1 body weight. The odds ratio of fumonisin exposure from maize hybrid 614 (H614) were: two times higher compared with non-H614 maize (p = 0.089); and five times higher when the maize was grown without fertilizer (p = 0.004). Sorting maize before storage reduced the percentage of families with unacceptable exposures to 6%. Therefore, the results imply that planting of the non-H614 seeds using fertilizers combined with pre-storage sorting of maize significantly minimizes fumonisins exposure in Rombo. A field experiment to verify these findings is needed.

Development of chromatographic method for the determination of degree of polymerisation of polyglycerols and polyglycerol fatty acid esters

SummaryFrom polyglycerol samples, pure standards of tri and tetraglycerol were obtained using a column chromatographic technique. Polyglycerols were derivatised to trimethyl silyl derivatives to obtain gas chromatographic identification of all linear, branched and cyclic diglycerol isomers and all linear and branched triglycerols. Moreover, quantitative gas chromatographic analysis of the di-, tri- and tetraglycerol content of a polyglycerol sample was developed.Finally a method to characterise, on a quantitative basis, the polyglycerol content of polyglycerol fatty acid esters was developed. It consisted of saponifying the esters, without affecting the degree of polymerisation of the polyglycerols, followed by gas chromatographic analysis of the isolated polyglycerol fraction.