Food Preservation Final Presentation 20-12-2012

8/19/2019 Food Preservation Final Presentation 20-12-2012

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MICROBIOLOGY OF IRRADIATED

FOODS


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What is Food Irradiation?

Food irradiation is a process in which oodprod!cts are e"posed to a contro##ed a$o!nto radiant ener%& to increase the saet& o the

ood and to e"tend she# #ie o the ood'E"pos!re o oods to ioni(in% radiation in or$ o

%a$$a radiation) *+ra&s and e#ectron ,ea$s todestro& patho%enic $icroor%anis$s'

Li-e paste!ri(ation o $i#- and press!recoo-in% o canned oods) treatin% ood withioni(in% radiation can -i## ,acteria andparasites that wo!#d otherwise ca!se

ood,orne disease'


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Microbes

Food can become contaminated by microbes. Microbes include…

• Bacteria: consist of only one cell (single-celled), have a cell

wall, have no nucleus or mitochondria.Salmonella bacteria

(causes food poisoning)

• Protists: very diverse group. ave a nucleus, can be either single or

multi-celled. Some have cell walls, others have cell membranes.

!lasmodium (causes malaria)

• Fungi, mold & yeast: ave a nucleus. "ither single or multi-

celled. #on$t ma%e own food, must land on their food source

or starve.

Mold that caused !otato Famine (&') in *reland


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Meas!re$ents o

Radiation

One %ra&.G&/ is the a,sorption o one 0o!#e o

radiation ener%& ,& one -i#o%ra$ o $atter 1 G& 2 1 34-%

Gra& .G&/ 2 155 rads .radiation a,sor,eddose/

6i#o%ra& .-G&/ 2 1555 G&


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Wh& Irradiate?

Low Dose .71 -G&/Contro# insectsInhi,it $at!ration

Inhi,it spro!tin%

Medi!$ Dose .1+15 -G&/E"tend she# #ie

Red!ce $icroor%anis$ #e8e#

9i%h Dose .: ;5 -G&/Steri#i(e + ana#o%o!s to cannin%

Deconta$inate certain ood additi8es) e'%')spices


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Foods s Re%!#ations All foods Arthropod Control 1 kGy maxFresh Foods Maturation Inhibition 1 kGy maxSpices/Seasonins Microbial Control !" kGy max#oultry Microbial Control ! kGy maxSeeds for sproutin Microbial Control $ kGy maxShell es Microbial Control ! kGy maxMeat and meat byproducts Microbial Control % kGy/& kGyMolluscan shellfish Microbial Control '(' kGy maxFresh lettuce and spinach Microbial Control % kGy max


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What irradiation can

e#i$inate?E' Co#i

Sa#$one##a

Ca$po,acter

To"op#as$a or%anis$s

Listeria

Shi%e##a


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Appro"i$ate doses o radiationneeded to -i## 8ario!s or%anis$s

)ranisms *ose +kGy,

-iher animals "(""' to "(1

Insects "("1 to 1

.onspore formin bacteria "(' to 1"

0acterial spores 1" to '"

iruses 1" to 2""


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T&pica# irradiationD+8a#!es o patho%ens

kGy

)ranism Fresh +refrierated, Fro3en

Camplobacter jejuni "("$ 4 "(2" "(21 4 "(!2

E. Coli )1'&5-& "(2% 4 "(2& "(!1 4 "(%%

Staphlococcus aureus "(26 4 "(6" "(!" 4 "(%'

Salmonella spp. "(!" 4 "($" "(%" 4 1(!"

Listeria monocytogenes "(2& 4 1("" "('2 4 1(!"

#-value is e+uivalent to radiation dose re+uired

to reduce a bacterial population


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T&pica# irradiationD+8a#!es o patho%ens

kGy

)ranism Fresh +refrierated,

Clostridium botulinumspores

1("" 4 !(6"

Toxoplasma "(%" 4 "(&"

Trichinella spiralis "(!" 4 "(6"

#-value is e+uivalent to radiation dose re+uiredto reduce a bacterial population


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Eect o irradiation on she# #ie o resh

$eatsSpoi#a%e or%anis$s) especia##& pse!do$onas)

are s!scepti,#e to #ow dose irradiation

Spoi#a%e o #ow dose irradiated $eats $a& ,ed!e to &east or Moraxella spp' .increased #a%ti$e/


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Meat product

Dose

(kGy)

ntreated

s!el" li"e

(days)

#rradiated s!el"

li"e (days)

Bee" $.% $'

Bee" top round $. *++ $*

Bee" burgers +.% *+ $-$*

Bee" cuts $. /0 1

2orned bee" . +$+ '%

Pork loins ' +

Ground pork + * ++.%

3amb (4!ole/minced) $.% 1 $*'%

Shelf life e/tension of fresh meat


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Meat IrradiationDece$,er @;) 1 Federa# Re%isterEecti8e date Fe,r!ar& @@) @555

Ioni(in% radiation appro8ed or !se

Co,a#t+5) Cesi!$+1;) *+ra& $achines)E#ectron acce#erators

Dosa%e' -G& i reri%erated

'5 -G& i ro(en


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App#ications o ood irradiation


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Efect on micro-organisms

The reacti8e ions prod!ced ,& irradiatin% oodsin0!re or destro& $icro+or%anis$s i$$ediate#&) ,&chan%in% the str!ct!re o ce## $e$,ranes and

aectin% $eta,o#ic en(&$e acti8it&' 9owe8er) a$ore i$portant eect is on deo"&ri,on!c#eic acid.DA/ and ri,on!c#eic acid $o#ec!#es in ce##n!c#ei) which are reH!ired or %rowth andrep#ication'


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Microbial destruction by irradiation: A) Pseudomonassp' B) Salmonella sp' C) Bacillus cereus D)

Deinococcus radiodurans E) t&pica# 8ir!s'


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D+8a#!es o i$portant patho%ens

*1" 4 7he radiation dose needed to inacti8ate 9": of the microbial load

in the food medium


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Nutritional and sensory value

Efect o irradiation on water-soluble vitamins inselected oods


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A comparison o vitamin contents o heat sterilized andirradiated (58 !y at "5#$% chicen meat


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Efect on pacaging


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Food Appro8ed =se Ma"i$!$ Dose

Spices and dr&8e%eta,#e seasonin%

deconta$inates and contro#sinsects and $icroor%anis$s

;5 -G&

Dr& or deh&drateden(&$e preparations

contro#s insects and$icroor%anis$s

15 -G&

A## oods contro#s insects 1 -G&

Fresh oods de#a&s $at!ration1 -G&

Documents

Food Preservation Final Presentation 20-12-2012