HURDLE CONCEPTINTERMEDIATE MOISTURE FOODS HURDLE TECHNOLOGY: Hurdle technology is a method of ensuring that pathogens in food products can be eliminated or controlled Means Food products will be safe for consumption Shelf life will be extended Hurdle technology usually works by combining more than one approach These approaches can be thought of as "hurdles" the pathogen has to overcome if it is to remain active in the food The right combination of hurdles can ensure all pathogens are eliminated in the final product HURDLES IN A FOOD SYSTEM ARE: I high temperature during processing II Low temperature durining storage III Increasing the acidity IV Lowering the water activity or Redox potential V Presence of preservatives According to the type of pathogens and how risky they are, the intensity of the hurdles can be adjusted individually to meet consumer preferences in an economical way, without compromising the safety of the product HURDLES: Each hurdle aims to eliminate, inactivate or at least inhibit unwanted microorganisms Common salt or organic acids can be used as hurdles to control microbials in food Many natural antimicrobials such as nisin, natamycins and other bacteriocins, and essential oils derived from rosemary or thyme, also work well Principal hurdles used for food preservation Parameter Symbol Application High temperature F Heating Low temperature T Chilling, Freezing Reduced water activity aw Drying, curing, conserving Increased acidity pH Acid addition or formation Reduced redox potential Eh Removal of Oxygen Or addition of ascorbate Biopreservatives Competitive flora such as microbial fermentation Other preservatives Sorbates, sulfites, nitrites PHYSICAL HURDLE Aseptic packaging, electromagnetic energy (microwave, radio frequency, pulsed magnetic fields, high electric fields), high temperatures(blanching, pasteurization, sterilization, evaporation, extrusion, baking, frying), ionizing radiation, low temperature (chilling, freezing), modified atmospheres, packaging films (including active packaging, edible coatings), photodynamic inactivation, ultrahigh pressures, ultrasonication, ultraviolet radiation PHYSIOCHEMICAL HURDLE Carbon dioxide, ethanol, lactic acid, lactoperoxidase, low pH, low redox potential, low water activity, Maillard reaction products, organic acids, oxygen, ozone, phenols, phosphates, salt, smoking, sodium nitrite/nitrate, sodium or potassium sulphite, spices and herbs, surface treatment agents MICROBIAL HURDLE Antibiotics, bacteriocins, competitive flora, protective cultures INTERMEDIATE-MOISTURE FOODS (IMF) Adjustment and control of water activity to preserve semimoist foods has attracted increasing attention Intermediate-moisture foods or semimoist foods, in one form or another, have been important items of diet for a very long time Generally, they contain moderate levels of moisture, of the order of 20- 50% by weight, which is less than is normally present in natural fruits and 'vegetables, but more than is left in conventionally dehydrated products In addition, 'intermediate-moisture foods contain sufficient dissolved solutes to decrease water activity below that required to support microbial growth As a consequence, intermediate-moisture foods not require refrigeration to prevent microbial deterioration There are various kinds of intermediatemoisture foods: natural products such as honey; manufactured confectionery products high in sugar, jellies, jams, and bakery items such as fruit cakes; and partially dried products including figs, dates etc In all of these products, preservation is partially from high osmotic pressure associated with the high concentration of solutes; in some, additional preservative effect is contributed by salt, acid, and other specific solutes ... combination of hurdles can ensure all pathogens are eliminated in the final product HURDLES IN A FOOD SYSTEM ARE: I high temperature during processing II Low temperature durining storage III Increasing... extrusion, baking, frying), ionizing radiation, low temperature (chilling, freezing), modified atmospheres, packaging films (including active packaging, edible coatings), photodynamic inactivation,... Principal hurdles used for food preservation Parameter Symbol Application High temperature F Heating Low temperature T Chilling, Freezing Reduced water activity aw Drying, curing, conserving Increased