Presentation on theme: "PRESERVATION TECHNOLOGIES FOR FRESH FRUITS AND VEGETABLES: COLD STORAGE, MODIFIED ATMOSPHERE PACKAGING AND CONTROL ATMOSPHERE STORAGE 1 ST WORKSHOP January,"— Presentation transcript:
PRESERVATION TECHNOLOGIES FOR FRESH FRUITS AND VEGETABLES: COLD STORAGE, MODIFIED ATMOSPHERE PACKAGING AND CONTROL ATMOSPHERE STORAGE 1 ST WORKSHOP January, 2002 Istanbul, Turkey Financial support by the Commission of the European Union under MEDA programme is acknowledged (Thematic Network ICA3-C ) Profª. Mª TERESA SANCHEZ
SPANISH FRUITS AND VEGETABLES: PRODUCTION, IMPORTATIONS and EXPORTATIONS
FOOD CONSUMPTION IN THE E.U. MEDITERRANEAN COUNTRIES
PERISHABILITY AND PRODUCE LOSES Have accurate control of temperature. Reduce microbial loading. Control and/or modify the packaging atmosphere. Deter enzymatic browning. Maintain all of the above while offering a consistent, predictable quality level for all deliveries. THE EMPHASIS OF ANY FRUIT AND VEGETABLE PROGRAM IS TO:
COLD STORAGE OF FRUITS AND VEGETABLES COLD CHAIN REFRIGERATED TRANSPORT
COOLING PROCESS 1. Reducing respiration and degradation by enzymes. 2. Reducing water loss and wilting. 3. Slowing the growth of decay organisms. 4. Reducing the production of ethylene, the natural ripening agent. 5. Providing time for proper handling and processing.
The most effective way to maintain quality and safety of fresh fruits and vegetables and their products is to maintain the COLD CHAIN, including the optimum range of relative humidity, throughout the postharvest life of the commodity. MAXIMIZE THE SELF-LIFE MINIMIZE SHRINKAGE
REFRIGERATED TRANSPORT TEMPERATURE CONTROLLED TRANSPORT
PROBLEMATICS OF FOOD PRESERVATION BY REFRIGERATION Requires continuous expense. The cold chain (production, transport, store, consumption) should not be broken. Problems of interruption of cooling machine power and/or shortage of cooling agent (ice, eutectic mixtures). Reduce enzymatic activity but do not kill, implies T<6 ºC for a few days but T<-18 ºC for a few months. Cooling increases relative humidity and increases surface fungi. Packed enclosure prevents it, but it asphyxiates vegetables. (Ambient humidity not relevant for frozen food.) In mixed spaces some food give odours (potatoes) and others take (dairy). Some stores require ventilation for fresh air or air treatment for controlled atmosphere.
CONTROLLED ATMOSPHERE STORAGE OF SELECTED FRUITS AND VEGETABLES CO 2 and O 2 concentration Relative Humidity Temperature
CONTROLLED ATMOSPHERE STORAGE Presence and quantity of: CO 2 O 2 Ethylene Products in optimum conditions: Type Variety Origin Climatic background PRODUCTS: Life can be extended by 30% Losses and diseases are reduced by %
Maximum concentration of CO 2 and minimum concentration of O 2 in AC storage Kader, 1980
CA MANIPULATIONS Initial low oxygen stress treatment (ILOS). High CO 2 shock treatments. A range of O 2 /CO 2 concentrations. CA combined with other treatments as a possible replacement for SO 2. Lower values of O 2 and CO 2 Better gas-tight insulation techniques Computer control systems
MODIFIED ATMOSPHERE PACKAGING OF SELECTED FRUITS AND VEGETABLES PUTTING THE PRODUCT TO SLEEP
Produce generate their own atmosphere in plastic bags The rate of respiration of the commodity The properties of the film The storage temperature Depending on:
Optimum CO 2 and O 2 concentration in MAP Broccoli 5:2; asparagus 10:10; lettuce 2:2; peaches 6:1.5; pears 2:2; carrots 0:21; blueberries 6:1.5 Optimum gas levels can vary according to: Cultivar or genotype Production area Harvest maturity Other factors
The potential positive and negative effects MAP has on the Food Industry Davies et al., 1995
MODIFIED ATMOSPHERE Produced naturally by respiration PASSIVE M.A. The permeability characteristics of the film determine the equilibrium gas concentration achieved in the package. Produced by the application of gas flushing techniques EQUILIBRIUM M.A. The actual equilibrium MA attained within a package will also depend on factors such as the prepared form of the vegetable studied, the rate of respiration at storage temperature, the pack volume and fill-weight, and the surface areas for gas exchange.
GENERAL EFFECTS OF MAP ON MICRO-ORGANISMS Not well studied. Gram negative bacteria (Pseudomonas) more sensitive to CO 2 than Gram positive. CO 2 at sufficient concentration can inhibit the growth of spoilage moulds.
FACTORS TO CONTROL IN MAP FOOD HYGIENE TEMPERATURE CONTROL STOCK ROTATION QUALITY ASSURANCE TESTS MICROBIOLOGICAL TESTING SEAL INTEGRITY GAS ANALYSIS TEMPERATURE MONITORING
FUTURE OF MAP 1OPTIMISING MAP OF A VARIETY OF FRESH PRODUCTS UNDER VARIOUS STORAGE CONDITIONS. 2TESTING MAP FILMS FOR CLIENTS. 3EVALUATING EDIBLE COATINGS. FOCUS AREAS OF MAP RESEARCH:
ENVIRONMENTAL IMPACT OF PRESERVATION TECHNIQUES OF FRUITS AND VEGETABLES CFCs, the predominant refrigerants used in reefer containers. Proposed restrictions on HFCs become a reality, refrigerated transportation will face serious challenges in finding acceptable substitutes.
QUALITY AND CONSUMER ACCEPTANCE High quality fruits and vegetables are one of today's wonders with regard to Spanish food supply. Unfortunately, many Spanish fruit and vegetable growers believe that once a high quality product is produced, their problems are over. In reality, their troubles could be just beginning. It has been estimated that more than 40 % of perishable commodities are lost after production. Price received for produce is determined by quality at the marketplace.
Direct contact between the seller and the consumer results in the consumer being able to select the particular items and enabling the seller to react quickly in response to consumer demands. This ensures a high level of consumer satisfaction.
Variables consumers perceive as a reflection of produced quality: Producers who are able to produce and package their produce in such a way to enhance these variables are the most successful in the market place. Texture: Crispness and freshness. Flavor and taste. Nutritive value. Price.
(1) The quality inspection procedures that must be carried out (Commission Regulation 2251/92 of 29 July 1992), (2) What quality they must have (Common Quality Standards' that have been promulgated throughout the years), and (3) The maximum limits of pesticide residues admitted and how they should be controlled (Council Directive 76/895/EEC, 90/642/EEC and 93/58/EEC). Within the Regulation applied to foodstuffs, fruit and vegetables must fulfill the provisions on labels (Council Directive 79/112/EEC and the one that regulates the quantity of products in the packages (Council Directive 76/211/EEC). How to assure the quality of a product? How to make commerce easier?
January, 2002 Istanbul, Turkey Financial support by the Commission of the European Union under MEDA programme is acknowledged (Thematic Network ICA3-C ) Profª Mª TERESA SANCHEZ THANK YOU VERY MUCH PRESERVATION TECHNOLOGIES FOR FRESH FRUITS AND VEGETABLES: COLD STORAGE, MODIFIED ATMOSPHERE PACKAGING AND CONTROL ATMOSPHERE STORAGE 1 ST WORKSHOP