Effectiveness of some recent antimicrobial packaging concepts

A new type of active packaging is the combination of food-packaging materials with antimicrobial substances to control microbial surface contamination of foods. For both migrating and non-migrating antimicrobial materials, intensive contact between the food product and packaging material is required and therefore potential food applications include especially vacuum or skin-packaged products, e.g. vacuum-packaged meat, fish, poultry or cheese. Several antimicrobial compounds have been combined with different types of carriers (plastic and rubber articles, paper-based materials, textile fibrils and food-packaging materials). Until now, however, few antimicrobial concepts have found applications as a food-packaging material. Antimicrobial packaging materials cannot legally be used in the EU at the moment. The potential use would require amendments of several different legal texts involving areas such as food additives, food packaging, hygiene, etc. The main objective of this paper is to provide a state of the art about the different types of antimicrobial concepts, their experimental development and commercialization, and to present a case study summarizing the results of investigations on the feasibility of a low-density polyethylene (LDPE)-film containing triclosan to inhibit microbial growth on food surfaces and consequently prolong shelf-life or improve microbial food safety. In contrast with the strong antimicrobial effect in in-vitro simulated vacuum-packaged conditions against the psychrotrophic food pathogen L. monocytogenes, the 1000 mg kg(-1) containing triclosan film did not effectively reduce spoilage bacteria and growth of L. monocytogenes on refrigerated vacuum-packaged chicken breasts stored at 7 degrees C

Study on antimicrobial activity of aq food packaging material containing potassium sorbate

The feasibility of EVA/LLDPE films containing 1, 2 and 5% (w/w) K-sorbate to inhibit microbial growth and as a consequence prolong shelf-life of foods was investigated. Based on weight loss experiments it was shown that K-sorbate is very suitable for incorporation in LLDPE because of its heat stability during extrusion. After 3 weeks, resp. 6.4, 2.8 and 5.7% of the incorporated sorbic acid was released into distilled water from films containing resp. 1, 2 and 5% (w/w) K-sorbate. The very limited migration of K-sorbate may be explained by the incompatibility of the polar salt with the apolar LLDPE. This limited migration could explain the very small inhibitory effect of the K-sorbate films on the growth of Candida spp., Pichia spp., Trichosporon spp. and Penicillium spp. During storage at 7 °C of cheese packaged in a 5% (w/w) K-sorbate film, no significant differences could be observed for yeast and mould growth on the cheese cubes compared to a reference film. The concentration of sorbic acid in the cheese did not exceed 14 ppm. This is much lower than the 1000 ppm K-sorbate needed to inhibit microbial growth. The results of this study confirm that the K-sorbate incorporated LLDPE film is not able to inhibit microbial growth in vitro on inoculated media and in vivo on cheese due to the insufficient release of K-sorbate from the film

Influence of acetate and CO₂ on the TMAO-reduction reaction by <i>Shewanella baltica</i>

In this work, the TMAO-reduction by Shewanella baltica, one of the representative spoilage organisms in modified atmosphere packaged marine fish fillets, and the effect of acetate and CO2 on this reduction were studied in vitro. The growth of S. baltica and the corresponding evolution of some compounds (acetate, lactate, pyruvate, glucose and trimethylamine (TMA)) were followed during storage at 4 degrees C in two types of broths. The first medium was a defined medium (pH = 6.8) to which lactate or pyruvate was added as hydrogen donor. Pyruvate showed to be more efficient as H-donor for S. baltica than lactate, as growth was much faster when equimolar amounts of pyruvate instead of lactate were present. Although the growth of S. baltica, when pyruvate is used as H-donor and no acetate is added, was not much inhibited by the CO2-atmosphere, CO2 had a pronounced effect on the studied reactions as it partly inhibited the reduction of pyruvate to acetate. The effect of acetate on this reaction was, on the other hand, not significant. To simulate the reactions occurring in situ, a buffered fish extract (pH = 6.8) was used. In spite of the neutral pH, the growth of S. baltica in this medium was highly inhibited by relatively small concentrations of acetate (S. baltica, from which the pathway seems to be less energy efficient. This can be deduced from the exceptional growth inhibition of S. baltica by small amounts of acetate. However, when practical storage times for fish (e.g. 6 days at 4 degrees C after packaging) are considered, growth and TMAO-reduction by S. baltica was completely inhibited during this period by 0.25% of acetate

Tools to support the self assessment of the performance of Food Safety Management Systems

Changes in food supply chains, health and demographic situations, lifestyle and social situations, environmental conditions, and increased legislative requirements have led to significant efforts in the development of quality and safety management systems in agribusiness and food industry worldwide (Ropkins and Beck, 2000; Efstratiadis, Karirti, and Arvanitoyannis, 2000; Jacxsens, et al, 2009a, Luning and Marcelis, 2009a). Nowadays, companies have implemented various quality assurance (QA) guidelines and standards, such as GMP and HACCP guidelines (like General Principles of food hygiene (Codex Alimentarius 2003), GFSI guidance document (GFSI (2007), and quality assurance standards (like ISO 9001:2008 (2008), ISO22000:2005 (2005), BRC (2008), and IFS (2007) into their company own food safety management system. The performance of such systems in practice is, however, still variable. Moreover, the continuous pressure on food safety management system (FSMS) performance and the dynamic environment wherein the systems operate (such as emerging pathogens, changing consumer demands, developments in preservation techniques) require that they can be systematically analysed to determine opportunities for improvement (Wallace, et al, 2005; Manning et al, 2006; Van der Spiegel et al, 2006; Cornier et al, 2007; Luning et al, 2009a). Within the European project entitled ‘PathogenCombat- EU FOOD-CT-2005-007081’ various tools have been developed to support food companies and establishments in systematically analysing and judging their food safety management system and its microbiological performance as basis for strategic choices on interventions to improve the FSMS performance. This chapter describes briefly principles of the major tools that have been developed and some others, which are still under still under construction

Heat adaptation of Escherichia coli K12: Effect of acid and glucose

AbstractThe objective of this work is to investigate the effect of the (possible) acid adaptation during growth in a glucose rich environment on the heat resistance of Escherichia coli K12 MG1655. E. coli cells were grown in TSB and/or TSB dextrose free broth until they reached the stationary phase. Afterwards, the stationary phase cells were added in TSB and/or TSB dextrose free broth and inactivation took place at 54oC and 58oC. It was observed that growth in a glucose rich environment leads to an increased heat resistance, most likely due to a certain level of acid and further heat adaptation via cross protection

Methodology for modeling the disinfection efficiency of fresh-cut leafy vegetables wash water applied on peracetic acid combined with lactic acid

A methodology to i) assess the feasibility of water disinfection in fresh-cut leafy greens wash water and ii) to compare the disinfectant efficiency of water disinfectants was defined and applied for a combination of peracetic acid (PAA) and lactic acid (LA) and comparison with free chlorine was made. Standardized process water, a watery suspension of iceberg lettuce, was used for the experiments. First, the combination of PAA + LA was evaluated for water recycling. In this case disinfectant was added to standardized process water inoculated with Escherichia coli (E. coli) O157 (6 log CFU/mL). Regression models were constructed based on the batch inactivation data and validated in industrial process water obtained from fresh-cut leafy green processing plants. The UV254(F) was the best indicator for PAA decay and as such for the E. coli O157 inactivation with PAA + LA. The disinfection efficiency of PAA + LA increased with decreasing pH. Furthermore, PAA + LA efficacy was assessed as a process water disinfectant to be used within the washing tank, using a dynamic washing process with continuous influx of E. coli O157 and organic matter in the washing tank. The process water contamination in the dynamic process was adequately estimated by the developed model that assumed that knowledge of the disinfectant residual was sufficient to estimate the microbial contamination, regardless the physicochemical load. Based on the obtained results, PAA + LA seems to be better suited than chlorine for disinfecting process wash water with a high organic load but a higher disinfectant residual is necessary due to the slower E. coli O157 inactivation kinetics when compared to chlorine.Ciencias de la Alimentació

Supercritical CO2 for the drying and microbial inactivation of apple's slices

Supercritical CO2 (Sc-CO2) drying has been recognized as a promising low temperature drying technique for food products. In this regard, this work focuses on the feasibility of Sc-CO2 drying of apple’s slices: both the microbiological stability and mechanical behavior of the test product after the process have been investigated in dependence from different process parameters, namely drying time, pressurization time, and depressurization time. The microbiological stability was determined for both inoculated pathogenic bacteria (Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes) and naturally present microorganisms (yeasts and molds, mesophilic bacteria and spores and Enterobacteriaceae). Results demonstrated a complete inactivation of pathogenic bacteria under the detection limit (&lt;1 CFU/g) just after the pressurization (10 min) and depressurization (20 min) phases. After the same steps, a strong reduction of vegetative bacteria and yeasts and molds was also observed in comparison with air drying and freeze drying samples. As regards the mechanical behavior, the Young Modulus, measured before and after the CO2 processes to provide a measurement of samples’ stiffness, resulted dependent from the final water activity, but independent from the length of pressurization and depressurization phases at longer drying time. Overall, these results are promising to foster the development of the technology at industrial level

Methodology for modeling the disinfection efficiency of fresh-cut leafy vegetables wash water applied on peracetic acid combined with lactic acid

A methodology to i) assess the feasibility of water disinfection in fresh-cut leafy greens wash water and ii) to compare the disinfectant efficiency of water disinfectants was defined and applied for a combination of peracetic acid (PAA) and lactic acid (LA) and comparison with free chlorine was made. Standardized process water, a watery suspension of iceberg lettuce, was used for the experiments. First, the combination of PAA + LA was evaluated for water recycling. In this case disinfectant was added to standardized process water inoculated with Escherichia coli (E. coli) O157 (6 log CFU/mL). Regression models were constructed based on the batch inactivation data and validated in industrial process water obtained from fresh-cut leafy green processing plants. The UV254(F) was the best indicator for PAA decay and as such for the E. coli O157 inactivation with PAA + LA. The disinfection efficiency of PAA + LA increased with decreasing pH. Furthermore, PAA + LA efficacy was assessed as a process water disinfectant to be used within the washing tank, using a dynamic washing process with continuous influx of E. coli O157 and organic matter in the washing tank. The process water contamination in the dynamic process was adequately estimated by the developed model that assumed that knowledge of the disinfectant residual was sufficient to estimate the microbial contamination, regardless the physicochemical load. Based on the obtained results, PAA + LA seems to be better suited than chlorine for disinfecting process wash water with a high organic load but a higher disinfectant residual is necessary due to the slower E. coli O157 inactivation kinetics when compared to chlorine.Ciencias de la Alimentació