Methods for preservation of foodstuffs

A method for inactivating microorganisms on the surface of a packaging material or foodstuff comprising the steps of

• providing a packaging material of foodstuff surface to be sterilized,
• applying an absorption enhancing agent to said surface in sufficient amount such that at least about 10% of the incident light is absorbed within a 10 micron thick superficial layer of said surface, and
• illuminating said surface having said absorption enhancing agent applied thereto with at least one pulse of high intensity incoherent polychromatic light having a duration in the range of from about 0.001 to about 100 milliseconds, an energy distribution such that at least about 70% of the energy of said pulse is distributed in the wavelength range of from about 170 nanometers to about 2600 nanometers and an energy density of from about 0.01 to about 50 joules per square centimeter of said surface.

A method for preserving food products, comprising the steps of applying to the entire surface of the food product a plurality of intense incoherent light pulses having a duration from about 1.times.10.sup.-6 to 1.times.10.sup.-1 second, an energy density in the range of from about 0.01 to 50 joules per square centimeters and a broadband wavelength distribution such that at least 70% of the light is in the wavelength range of from 170 nanometers to 2600 nanometers to inactive enzymes and bacteria and molds at the surface and within the near surface region of the food product.

A method of inactivating microorganisms on a surface of a food product or packaging material comprising exposing the food product or packaging material surface to between about 1 and about 50 pulses of light spaced not more than about 10 seconds apart, the light having most of its energy distributed in the wavelength between 300 and 2500 nanometers, each pulse having a duration of between about 0.1 and about 1.0 millisecond, each pulse providing an energy density at the surface of between about 2 and about 20 joules per cm.sup.2 .

A method for preserving a perishable foodstuff having surface enzyme activity resulting from the presence of a plurality of active enzymes, to provide a preserved food product having improved keeping qualitites, comprising the steps of

• providing a solid food product to be treated having degradative enzymes at the food product surface,
• illuminating the surface of said solid food product with at least one very short pulse of intense polychromatic incoherent light having a duration in the range of from about 0.001 to about 100 milliseconds, an energy density in the range of from about 0.01 to about 50 joules per square centimeter at the surface of the food product, a wavelength distribution such that at least about 70 percent of the energy of said pulse of intense polychromatic incoherent light is distributed at wavelengths between 170 nanometers and 2600 nanometers, substantially instantaneously with the duration of said first polychromatic incoherent light pulse, to substantially simultaneously reduce the activity of each of a plurality of at least two different specific enzymes to less than 75 percent of their respective initial values at the food product surface, to provide a preserved food product having increased shelf life.