Non thermal methods

Do I need to refrigerate butter? Fat-in-water, to water-in-fat emulsion “Compartmentalization”

Food processing Thermal (>95% of foods in US) Non-thermal Microwave and radio frequency Ohmic heating Non-thermal Irradiation UV High-intensity pulsed light Ionizing radiation Cold atmospheric plasma processing Physical methods High hydrostatic pressure (HPP, HHP, UHP, Pascalization) Pulsed electric fields Oscillating magnetic fields

High pressure processing (high hydrostatic, ultra high pressure) Chamber 215 Liter volume processor Packaged Food + water High pressure pump (Flow International)

Pressure of 380-640 Mega Pascals (MPa) How much is 400 MPa? 1 atm = 0.1 MPa Look to the left; Deepest part of ocean is 110 MPa - (Flow International) Slide from S. Knabel

Batch process, industrial scale http://www.avure.com/food/

Inactivation of E. coli O157:H7 Before After Black et al., J. Appl. Microbiol. 108:1352

HPP treated beef: fresh, frozen, cooked P. Picouet, M. Pérez-Juan, and C.E. Realini , 2008 Top view Side view Slide from Dr. Catherine Cutter

But… Slide from Dr. Catherine Cutter Eastern Meat Packers Assn. Christopher R. Raines 27 Sept. 2011

The good and the bad Advantages: Disadvantage: Inactivates fungi>gram negative>gram positive Works well with “compressible” foods (sauces, jellies, guacamole, etc); “Fresher” flavor; Viewed as less “processed” Disadvantage: Doesn’t work with “fragile” foods; Damages cells of biological tissue (fruits, vegetables, meats); Doesn’t work well with some fatty foods (adiabatic heating = 3 C per 100 MPa); Doesn’t inactivate spores very well (Niche market technology)

http://www.hormelfoodservice.com/hpp/

UV treatment CiderSure UV system Validated to achieve 5-log reduction Thin film allows efficient flow through Rate automatically adjusted based on absorbance coefficient of juice Escherichia coli O157:H7 and Cryptosporidium parvum Slide from L. LaBorde

Sensor regulates pump flow Flow control UV-A: 315-400 nm UV-B: 280-315 nm UV-C: 200-280 nm Sensor regulates pump flow UV bulb Slide from L. LaBorde

Mechanism of inactivation UV-C www.eplantscience.com

Factors impacting UV effectiveness Turbidity Presence of UV absorbing molecules Microbial species Implicit factors - photolyase Organism Exposure required (J/m2) Adapted first Escherichia coli 50-100 180-280 Salmonella sp. 130-140 190-250 P. aeruginosa 110 190 Mycobacterium smegmatis 200 270 Rotavirus 350 Not applicable http://www.fda.gov/Food/FoodScienceResearch/SafePracticesforFoodProcesses/ucm103137.htm Ramaiah D et al. PNAS 1998;95:12902-12905

Irradiation Gamma rays: emitted from nucleus of cobolt 60 or cesium 137 X-rays: generated by reflecting high-energy stream of electrons off a heavy metal such as Tungston or Tantalum Electron processing beam: “Electron gun” (high energy electron accelerator) focuses Wikipedia

Radiolysis of water Gray = 1 joule/kg https://www.ceessentials.net/article3.html http://journal.frontiersin.org/Journal/10.3389/fphar.2012.00094/full Gray = 1 joule/kg

Microbial kill by irradiation

Radicidation: removal of pathogens Radurization: prolong shelf life Delay fruit ripening Radicidation: removal of pathogens Radurization: prolong shelf life “Radura” http://www.gatewayamerica.net/sample-page/

Advantages/disadvantages Proven technology; More even and able to penetrate than heat; Less costly to operate than heat processing; Disadvantages Initial expense; Dairy, meats, sensitive to oxidation; Low doses sometimes required aren’t effective against spores, viruses; Consumer acceptance.

Food processing Thermal (>95% of foods in US) Non-thermal Microwave and radio frequency Ohmic heating Non-thermal Irradiation UV High-intensity pulsed light Ionizing radiation Cold atmospheric plasma processing Physical methods High hydrostatic pressure Pulsed electric fields Oscillating magnetic fields