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JOURNAL of FOOD PROCESSING and PRESERVATION SEP 2000 Vol‐24.4. DEVELOPMENT of A PROCESS FOR DETECTING NONTHERMAL EFFECTS of MICROWAVE ENERGY ON MICROORGANISMS AT LOW TEMPERATURE 1
Author(s) -
KOZEMPEL MICHAEL,
COOK RICHARD D.,
SCULLEN O. JOSEPH,
ANNOUS BASSAM A.
Publication year - 2000
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.2000.tb00420.x
Subject(s) - microwave , heat exchanger , tube (container) , refrigeration , thermal energy , materials science , thermal , annulus (botany) , chemistry , composite material , thermodynamics , physics , quantum mechanics
We developed an experimental process capable of isolating thermal and nonthermal effects of microwave energy relative to the destruction of microorganisms at low temperature. the concept combines instantaneous energy input to the food system by microwaves with rapid removal of thermal energy. the process used a double tube heat exchanger inside a continuous microwave dryer. the outer tube was transparent to microwaves, whereas the inner tube was stainless steel and was used for cooling the system. the microwave energy, 5–6 kW power, was absorbed by the process fluid in the annulus. the cooling water flowing in the inner tube removed the thermal energy from the process fluid to control temperature at or below 45C. the process was at turbulent flow to assure a uniform temperature and dwell time. There were no detected nonthermal effects from microwave energy for yeast, Pediococcus sp., Escherichia coli, Listeria innocua , or Enterobacter aerogenes in various test fluids, such as water, liquid egg, beer, apple juice, apple cider, and tomato juice.