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Novel approaches in seafood preservation techniques_Dr. Irshad A., LPT Division,IVRI, Izatnagar.

Novel approaches in seafood preservation techniques_Dr. Irshad A., LPT Division,IVRI, Izatnagar.



Fish are highly susceptible to spoilage, which is caused mainly by microbial growth and metabolism that produce amines, sulphides, alcohols, aldehydes, ketones, and organic acids. Spoiled products ...

Fish are highly susceptible to spoilage, which is caused mainly by microbial growth and metabolism that produce amines, sulphides, alcohols, aldehydes, ketones, and organic acids. Spoiled products have unpleasant and unacceptable off-flavours, making fish that is not well protected unsuitable for human consumption. Improving the safety and quality of seafood is important for both the consumers and the seafood industry. Ancient preservation techniques are not much effective in the large scale production of sea foods, its product processing and storage. Also these techniques have certain limitations such as loss of texture, favour, colour etc. So advance methods like irradiation, ultrasound, high intensity light etc are used for preservation, processing of fish and seafood product. Even though these are costly methods, they are cost effective in mass production and marketing.




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    Novel approaches in seafood preservation techniques_Dr. Irshad A., LPT Division,IVRI, Izatnagar. Novel approaches in seafood preservation techniques_Dr. Irshad A., LPT Division,IVRI, Izatnagar. Presentation Transcript

    • IntroductionWhy preservation is important?Seafoods are perishable productsShelf life is limited in the presence of oxygen andairVery good medium for aerobic spoilage organisms
    • Basis of preservationControl of temperature( Refrigeration & Freezing)Water activityMicrobial loadAvailability of oxygen
    • Ancient methods of preserving fishDrying:- Water activitySmoking:- Water activity & Microbial loadFreezing:- Temp controlCanning:- Microbial loadSalting:- Water activityFermentation and Pickling:- Water activity
    • 1. Modified Atmospheric Packaging (MAP) Air in side the pack is replaced with single gas or mixture of gas Used in various food product such as• Raw & cooked red meat• Poultry• Fruits• Coffee and tea• Vegetables• Bread and cheese• Fish and sea foods
    • Modified Atmospheric Packaging (MAP) MAP together with refrigeration is use in sea foodsShelf life depend on Raw materials Temperature Gas mixture and proportion- low conc. of O2 High conc of CO2 and N2 Gas/product ratio Packaging material used
    • Modified Atmospheric Packaging (MAP)Commercially used gases areCO2, O2, & N2CO, N2O, NO, SO2, Cl2 and ethaneXenon, Argon & HeliumCombinations usually used areCO2/N2/O2=40:30:30 for white fish and shellfishCO2/N2=60:40 for fatty and smoked fishIn1992 (UK sea food authority) a patent was issued for a gasmixture-50-80% CO2, 5-20% O2 and 27-45% Ar -slow down enzymatic reaction and microbial development
    • Modified Atmospheric Packaging (MAP)Success of MAPGMPsHACC ProgramsProper temperature control during storage and distributionDisadvantage:•Lower Temperature is needed•Growth and toxin production by Clostridium botulinum type E•There is a change in composition of micriflora in product
    • 2.IRRADIATION TECHNIQUE Old food preservation technique Began in 1957 Germany to improve quality of spicesPhysical treatment involving direct exposure of food product to electrons or EMRs to preserve food.For Sea foods preservation• Gamma rays• X-rays• Accelerated electron beams are used
    • 2.IRRADIATION TECHNIQUEFor Gamma rays:- Co 60 & Cs 137Mechanism:- Irradiation with high energy radiation leads to thebreakdown of chemical bond and form free radicals and ionsin microorganism, which leads their destruction. Dose rate:- 2 – 8 kGyUK Food Irradiation Legislation Permits only 3kGy radiationfor fish and shell fish.
    • 2.IRRADIATION TECHNIQUEDisadvantage:-•Undesirable sensory changes•Low conversion efficiency•Limited penetration in sea and shell foods•Licensing is tightly regulated•Consumer concern about Cs 137
    • 3. Ozone Preservation TechniqueEffectively Used in•water treatment•Cleaning and sterilization of plantsMechanism: Molecular Ozone and its Decomposed product are effectivelydestroy micro organism including bacteria, virus and fungi bytheir effect on microbial intercellular enzyme, nucleic acid, andother cellular components.
    • 3. Ozone Preservation TechniqueAdvantages:-O3 reduce the superficial contamination of fish as well as theformation of volatile N2 compound.O3 increase the shelf life of the fish products and sensory qualityDoes not produce any toxic residue
    • 4.Pulse Electric Fields method (PEF) Physical Non thermal Preservation Method. Use of electric field to eradicate food borne pathogen and to control spoilage microorganism in food. Used as a replacer of thermal pasteurization of foods Mainly Used in liquid foods and some fish productsEfficiency of PEF depends on; Electric field strength Treatment time Bacterial features
    • 4.Pulse Electric Fields method (PEF)Advantages:-It preserve quality attributes of foods.Improve nutritional value of some foodsIncrease sensory qualityControl the microbiological safety of product.Disadvantages:-•Ineffective in enzymes and spores•Safety concern in processing environment•Adverse effect in foods•Affect the texture and microstructure of meat and fish
    • 5.Ultraviolet (UV) Radiation tech.• Non thermal and environmental friendly• Exposure of the product to a germicidal light with a wavelength to inactivate bacteria and viruses.Classification of UV radiationsUV-A(Near UV) -315 to 400nmUV-B(Mid UV)- 280 to 315 nmUV-C(Far UV)- 100 to 280nm
    • 5.Ultraviolet (UV) Radiation tech.Mechanism:-•Micro-organism absorb UV light(at 254nm) Physical shiftingof electrons breaking bond in DNA preventing growth andreproduction.•UV-C is more effective than othersIn food industry mainly used forSterilization of food contact surfaceWater used of washing foodsAir sanitation in meat and vegetable processing plant.Reduction of pathogen in fruits, veg, red meat, fish and fishproduct, poultry etc
    • 5.Ultraviolet (UV) Radiation tech.
    • 6.Oscillatory Magnetic Fields(OMF) Non thermal physical process Usually used along with conventional preservation techniques First proposed in 1985, US patent to Hofmann. Very low degradation in sensory and nutritional property In OMF, Food is sealed in a plastic bag and subjected to 1 to 100 pulses in an OMF with a frequency between 5 and 500kHz at 0 to 50oC for a total exposure time 25 to 100 microseconds For seafood preservation- 5 to 50 Khz and intensity 5 to 50 Tesla is used.(The te sla (symbo l T) is the SIde rive d unit o f mag ne tic flux de nsity, co mmo nly de no te d as B)
    • 7. High Pressure Processing(HPP) Application of Very High Hydrostatic Pressure ranging from 100 to over 1000MPa at temp of 0 to 100oC, with varying holding time. Holding time depends on food. It inactivate enzymes and microorganisms Minimal effects on food quality First commercialized in Japan 1992 Used mainly in  Ham  Rice products  Fish and shellfish
    • 7. High Pressure Processing(HPP)Advantages:Increased shelf-life (2 to 4 times longer than the same productwithout HPP, stored at the same temperature).Easier and higher yield shucking and meat extraction (20% – 50%more meat).Product freshness.No Impact on sensory, nutritional or functional properties.Effective elimination of spoilage and pathogenic micro-organisms.Greater tolerance to cold chain abuse.
    • 7. High Pressure Processing(HPP)Limitations:High cost equipmentLong cycle timesIncreased metal fatigue.
    • 8.Ultrasound Preservation Technique
    • 8.Ultrasound Preservation TechniqueLimitationsHigh energy consumptionLong treatment timesComplex mode of actionNeed to be used in combination with another process(eg:heating)Undesirable sensory changes
    • 9. High Intensity Light Preservation Also called,Pulsed UV light, Pulsed light, Broad Spectrum White light. Alternative technique for thermal preservation Intense light pulse is used for preservation Bandwidth between 200 to 280 nm( UV-C)Mainly used for:- Surface sterilization of baked goods, veg, fruits sea foods and meats Micro-organisms such as L.monocytogenes, S. enteritidis, Ps. aerogenosa, B. cereus, St. aureus were reduced in 200 pulse light(ie pulse duration, 100ns)
    • 9. High Intensity Light PreservationLimitationsOnly applied for clean surfacesCause severe blindness on accidental exposureLimited use in opaque food stuffsProduce undesirable sensory changes
    • ConclusionFood preservation techniques extend shelf life of the products while maintaining food safety and qualityTo improve the effectiveness of preservation techniques, two or more tech can be combined.For efficient preservation, US, HIL, PEF etc on sea foods need to be investigated.