MadSci Network: Microbiology

Subject: effect of far infrared lamp in a domestic refrigerator

Date: Sun May 10 12:14:25 1998
Posted by Alejandro Ramirez
Grade level: teacher/prof
School: lancaster school
City: mexico State/Province: df
Country: mexico
Area of science: Microbiology
ID: 894820465.Mi

I have been very curious to know more of effects of the far infrared 
lamp, since my wife brought a new refrigerator ( goldstar).

The refrigerator has a far infrared lamp in the top of the food 
compartment, the aim of this lamp is to preserve meat with out freezing, 
we left some fresh beef for two weeks and it did not have any change in 
smell and color. 
We eat it without any complaint the next day.

I have performed some of the next home experiments:
I introduced a thermometer inside the fridge to check a difference of 
one degree (centigrade) on temperature on the surface of the meat when 
the infrared lamp is on and off.

I wrapped three pieces of meat, one with aluminum, one with transparent 
plastic film and another in side a glass bottle, the only one that 
survived was the piece inside the plastic film.

It seems to me that there is a green house effect???

The refrigerator manual says that infrared rays keeps the taste and 
the smell of the food for long by increasing the nucleic acid. 
(I have not found any paper on this topic)

I have found a paper on a similar topic if you would like to have a 
look to it.

TI Far-infrared irradiation effect on pasteurization of bacteria on or 
 within wet-solid medium
AU Hashimoto, Atsushi; Igarashi, Hideo; Shimizu, Masaru
AF Tokyo Univ of Agriculture & Technology 
AC Tokyo 
AY Jpn 
SE J Chem Eng Jpn 
ST Journal of Chemical Engineering of Japan 
SN 0021-9592 
IG 0078972 ISL n 6 SD Dec VOL v 25 YR 1992 
AT (Author abstract) NR 9 Refs AB 
The present purpose is to study the influence of far-infrared 
irradiation on pasteurization of Escherichia coli and Staphylococcus 
aureus on or within a model for wet-solid food. Agar medium was used 
as the food model. By determining the thermal resistances of the test 
bacteria, the pasteurization effect of far-infrared irradiation 
(radiative heating) was compared with that of hot-air heating 
(a conventional method) from the viewpoint of thermal death kinetics. 
It was found experimentally that far-infrared irradiation is more 
effective than hot-air heating for the test bacteria on the agar-plate.
Moreover, it is suggested that the surface temperature of the  
pasteurization sample irradiated by far-infrared radiation is higher 
than that measured by the  thermocouples. 
MH Food products 
CV Sterilization (cleaning) CV Infrared radiation CV Radiation effects 
CV Bacteria CV Moisture 
FL Wet solid food FL Far infrared irradiation FL Pasteurization 
TR X CL 822.2 CL 741.1 CL 801.2 CL 822.3 CL 641.1 
LA English DT JA TG CX XP p 666-671 OA 0890239 [APG089] XN
0000815 MN 0074346 YN 0056901 TN 0074039 DS EL UR SU JN93B

Dr. Alejandro Ramirez

Robert E. Peale wrote:

> Dear Dr. Ramirez,
> I'm unaware of the application of far infrared that you mention.  To 
> me it sounds like a scheme to cheat consumers out of their money.  
> Far-infrared is electromagnetic radiation of wavelength longer than 20 
> micrometers and shorter than about 1 mm.  A wavelength of 50 microns is 
> typical of thermal energy at room temperature.  FIR is strongly absorbed 
> by water and other molecules, mainly by exciting their rotational motion.
> The absorbed energy manifests itself as heat.  Far-infrared photons do 
> not have enough energy by far to break chemical bonds, and so 
> photo-chemistry is out of the question.  In other words, you can't 
> damage any living thing, including bacteria, with low intensity 
> far-infrared radiation.  Some biological effects of FIR have been 
> reported, but these experiments were performed by physicists with no
> experience in controlled biological techniques, and these results are 
> highly doubtful.  The most you would expect would be to warm the food 
> up a little (which would encourage bacteria to grow)  or to cook it, 
> if the source were really intense. We all know that cooking food helps
> preserve it, but a more efficient and cost effective way to do it than 
> with a ceramic coated lamp is by boiling, roasting, or frying.  
> Moreover, I don't see how simultaneous cooking by FIR and refrigeration 
> would be compatible, since they occur in opposite temperature regimes.

Re: effect of far infrared lamp in a domestic refrigerator

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