Food packaging is concerned with the preservation and protection of all types of foods and their raw materials, particularly from oxidative and microbial spoilage and also to extend their shelf-life characteristics. Increased use of synthetic packaging films has led to serious ecological problems due to their total non-biodegradability. Continuous awareness by one and all towards environmental pollution by the latter and as a result the need for a safe, eco-friendly atmosphere has led to a paradigm shift on the use of biodegradable materials, especially from renewable agriculture feedstock and marine food processing industry wastes. Such an approach amounts to natural resource conservation and recyclability as well as generation of new, innovative design and use. Their total biodegradation to environmentally friendly benign products such as CO 2 , water and quality compost is the turning point which needs to be capitalized and encashed. Polymer cross-linking and graft copolymerization of natural polymers with synthetic monomers are other alternatives of value in biodegradable packaging films. Although their complete replacement for synthetic plastics is just impossible to achieve and perhaps may be even unnecessary, at least for a few specific applications our attention and needful are required in the days to come. No doubt, eventually BIOPACKAGING will be our future.

Biodegradable films and composite coatings: past, present and future

Food packaging is concerned with the preservation and
protection of all types of foods and their raw materials,
particularly from oxidative and microbial spoilage and also
to extend their shelf-life characteristics. Increased use of
synthetic packaging films has led to serious ecological problems
due to their total non-biodegradability. Continuous
awareness by one and all towards environmental pollution
by the latter and as a result the need for a safe, eco-friendly
atmosphere has led to a paradigm shift on the use of biodegradable
materials, especially from renewable agriculture
feedstock and marine food processing industry wastes.
Such an approach amounts to natural resource conservation
and recyclability as well as generation of new, innovative
design and use. Their total biodegradation to
environmentally friendly benign products such as CO2, water
and quality compost is the turning point which needs to be
capitalized and encashed. Polymer cross-linking and graft
copolymerization of natural polymers with synthetic monomers
are other alternatives of value in biodegradable
packaging films. Although their complete replacement for
synthetic plastics is just impossible to achieve and perhaps
may be even unnecessary, at least for a few specific applications
our attention and needful are required in the days
to come. No doubt, eventually BIOPACKAGING will be our
future.

Biodegradable films and compositecoatings: past, present and future.

Minimally processed fresh (MPF) fruits and vegetables are good media for growth of microorganisms. They have been involved in outbreaks because of the consumption of products contaminated by pathogens. They are also sensitive to various spoilage microorganisms such as pectinolytic bacteria, saprophytic Gram-negative bacteria, lactic acid bacteria, and yeasts. Contamination of MPF fruits and vegetables occurs at every stage of the food chain, from cultivation to processing. Polluted environments during cultivation or poor hygienic conditions in processing increase the risk of contamination with foodborne pathogens. Although MPF fruits and vegetables may harbor psychrotrophic microorganisms such as fluorescent pseudomonads or Listeria monocytogenes, good control of refrigeration temperature limits growth of spoilage and pathogenic microorganisms. Modified atmospheres are often efficient to maintain or improve visual organoleptic quality of MPF fruits and vegetables, but their effects on microorganisms are inconsistent. Chemical disinfection can partially reduce the initial bacterial contamination; irradiation seems to be more efficient. The applications of legislations and quality assurance systems to control contamination, survival, and growth of foodborne pathogens in MPF fruits and vegetables are discussed.

The microbiology of minimally processed fresh fruits and vegetables

The market sales of ready-to-use fresh vegetables have grown rapidly in recent decades as a result of changes in consumer attitudes, especially consumption of fresh-cut lettuce and carrot due to their use in prepared salads. Chlorine solutions have been widely used to sanitise fruit and vegetables in the fresh-cut industry. However, the association of chlorine with the possible formation of carcinogenic chlorinated compounds in water has called into question the use of chlorine in food processing. There is a real need to find alternatives for preservation of fresh-cut fruit and vegetables in order to improve the efficacy of washing treatments. Alternatives or modified methods have been proposed, as antioxidants, irradiation, ozone, organics acids, modified atmosphere packaging, whey permeate, etc.; however, none have yet gained widespread acceptance by the industry. For this reason the development of alternatives and markers in order to measure the efficacy of these alternatives are needed.

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Extending and Measuring the Quality of Fresh-cut Fruit and Vegetables: a Review

Modelling respiration rate of fresh fruits and vegetables for modified atmosphere packages: a review

Modified atmospheres (MA), i.e., elevated concentrations of carbon dioxide and reduced levels of oxygen and ethylene, can be useful supplements to provide optimum temperature and relative humidity in maintaining the quality of fresh fruits and vegetables after harvest. MA benefits include reduced respiration, ethylene production, and sensitivity to ethylene; retarded softening and compositional changes; alleviation of certain physiological disorders; and reduced decay. Subjecting fresh produce to too low an oxygen concentration and/or to too high a carbon dioxide level can result in MA stress, which is manifested by accelerated deterioration. Packaging fresh produce in polymeric films can result in a commodity-generated MA. Atmosphere modification within such packages depends on film permeability, commodity respiration rate and gas diffusion characteristics, and initial free volume and atmospheric composition within the package. Temperature, relative humidity, and air movement around the package can influence the permeability of the film. Temperature also affects the metabolic activity of the commodity and consequently the rate of attaining the desired MA. All these factors must be considered in developing a mathematical model for selecting the most suitable film for each commodity.

D Zagory

Papers

Modified atmosphere packaging of fruits and vegetables.