HURDLE TECHNOLOGY

HURDLE TECHNOLOGY

Hurdle technology advocates the deliberate combination of existing and novel preservation techniques in order to establish a series of preservative factors (hurdles) that any microorganisms should not be able to overcome.

Consumer demand for more natural and fresh-like foods, which urges food manufacturers to use only mild preservation techniques (e.g. refrigeration, modified-atmosphere packaging and biopreservation), which makse the preservation even greater difficult task.

Commonly used hurdles

•High Temperature•Low temperature•Low water activity•Acidicity•Low redox potential•Competative microorganisms•Preservatives

Potential Hurdles for use in fish preservation

Physical hurdles

Physico chemical hurdle

Microbially derived hurdles

Miscellaneous hurdles

High Temperature: Sterilization, Pasteurization and Blanching

Low temperature : Chilling and Freezing

Ultraviolet radiation

Ionizing radiation

Electromagnetic energy ( Microwave energy, Radio frequency energy, Oscillating magnetic field pulses and High electric field pulses)

Photodynamic inactivation

Ultra high pressure

Ultrasonication

Packaging film (Plastic, multi layer, active coating and edible coating)

Modified atmospheric packaging (Gas packaging, Vacuum packaging, Moderate vacuum and active packaging)

Aseptic packaging

food microstructure

•Low water activity (aw) •Low pH & redox potential (Eh) •Salt •Nitrite •Nitrate•Carbon dioxide•Oxygen•Ozone •Organic acids •Lactic acid •Lactate•Acetic acid•Acetate•Ascorbic acid•Sulphate•Smoking•Phosphates•Glucono lctones•Phenols•Chelators•Surface treatment agents•Ethanol•Propyle glycol•Maillard reaction products•Spices & Herbs•Lactoperoxidas & Lysozyme

Physical hurdles Physico chemical hurdle

Competitive flora

Protective cultures

Bacteriocins

Antibiotics

Monolaurin

Free fatty acids

Chitosan

Chlorine

Microbially derived hurdles Miscellaneous hurdles

Hurdle Advantage Disadvantage

Low dose irradiation In active vegetative microorganismsIn package treatment Additional shelf life

Microbial spores resistantConsumer resistanceCapital costs

Modified atmospheric packaging Reduces oxidation and microbial spoilage

No significant effect on pathogen

Freezing Longer shelf life Thawing required Higher costs

High hydrostatic pressure In- package treatment Spores resistantPossibility of textural changes

Chemicals (pH, salt, spices) Low cost Impact on sensory quality

Protective cultures Effective against spore formers Cost of handling culturesHeat sensitivity

Bacteriocins Many are heat stableEffective against spore formers

Inconsistency of inhibitory effectDecompose during storage

Advantages and disadvantages of Hurdle technology