Biomedical Engineering Reference
In-Depth Information
considered when studying the degradation of vitamins. Fox et al. (
1995
) and Lakritz
et al. (
1995
) studied the loss of thiamine, ribofl avin and
-tocopherol due to gamma
irradiation of beef, lamb and pork
longissimus dorsi
, turkey breast and leg muscles.
Thiamine losses averaged 11 % per kGy and ribofl avin losses were 2.5 % per kGy
above 3.0 kGy. Irradiation resulted in a signifi cant decrease in
ʱ
ʱ
-tocopherol levels
in all of the meats studied. The rate of loss of
-tocopherol in turkey breast tissue
was greater than the other meats (Lakritz et al.
1995
).
Furan is listed as a possible human carcinogen by the Department of Health and
Human Services Report on Carcinogens (NTP
2011
) and the International Agency
for Research on Cancer (IARC
1995
). Furan was present in many thermally pro-
cessed foods such as soups and meat products that underwent a retort process. The
precursors of furan are sugars, ascorbic acid and/or fatty acids (Moro et al.
2012
).
Fan and Sommers (
2006
) investigated the generation of irradiation-induced furan in
aqueous solutions of some ingredients used in the manufacture of ready-to-eat
(RTE) meat products, and in eight RTE meat food products. Irradiation at doses up
to 4.5 kGy induced formation of furan in aqueous solutions of sodium-ascorbate,
sodium-erythorbate, glucose, honey, and corn syrup. Addition of Na-nitrite into
these solutions prior to irradiation completely eliminated, or signifi cantly reduced,
furan formation. Most of the non-irradiated RTE products purchased from local
markets contained less than 1 ng/g of furan, except for beef and turkey frankfurters
which contained 6-8 ng/g furan. Exposure of RTE food products to 4.5 kGy radia-
tion in the non-frozen state (5 °C) or to 10 kGy radiation in the frozen state (
−
18 °C)
did not signifi cantly increase furan levels in frankfurters. Irradiation treatments
reduced furan levels in frankfurters that contained more than 3 ng/g of furan.
Therefore, irradiation induces furan formation in solutions of many RTE food ingre-
dients, but not in RTE meat and poultry products.
ʱ
11.2.1.3
Microbiological Quality
Irradiation is an effective method to kill enteric pathogens associated with meat.
The populations of most common enteric pathogens such as
Campylobacter jejuni,
Escherichia coli
O157:H7,
Staphylococcus aureus, Salmonella
spp., and
Listeria
monocytogenes
can be signifi cantly decreased or eliminated by low-dose irradiation
(<3.0 kGy). However, enteric viruses and endospores of genera
Clostridium
and
Bacillus
are highly resistant to ionizing radiation (Thayer
1995
). Beef was the most
commonly reported vehicle for foodborne outbreaks of
E. coli
O157:H7 illness in
the U.S. from 1982 to 2002, accounting for 41 % of outbreaks (Rangel et al.
2005
).
In addition, many non-O157 Shiga toxin-producing
Escherichia coli
(STEC) are
now recognized as potential human pathogens.
L. monocytogenes
is a ubiquitous
bacterium and capable of proliferation in refrigerated temperatures. It is a frequent
post-process contaminant of ready-to-eat meat products. A number of food-borne
illness outbreaks and recalls have been attributed to
L. monocytogenes
in the U.S. in
recent years.
