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A s e p t i c P a c k a g in g o f G r a d e A D a i ry P r o d u c ts IA . L . R I P P E NFood Science Department , Mich igan Sta te Univers i ty , East Lansing 4 882 3

Abs t rac tSome new concepts will probably evolvefrom UHT-AP processing and packagingmethods. Future plants will probably bedesigned to restrict personnel and supplytraffic in critical processing and fillingareas. There is a good possibility that thefilling area will be at least partially iso-

lated from the rest of the plant. This areawould be constructed to provide more thannormal protection, thus guarding againstproduct recontamination. Filtered air sup-plying pressurized rooms for aseptic pack-aging will undoubtedly be commonplace innew plant design.Aseptic packaging machines are beingdeveloped with greater capacities and im-proved performance, to provide more confi-dence in achieving aseptic filling.Dairy farmers supplying milk for UHTtreatment must continue to produce high-quality raw milk. Raw milk will be evalu-ated in part on spore count, which will beincluded in the criteria for determiningquality. The industry and regulatory agen-cies should develop labeling uniformitywhich would give consideration to terminol-ogy for UHT- AP products. One industryleader has cautioned against possible "over-regulation" in the production and distribu-tion of UHT-AP products which couldinhibit the full potential benefits from themethod. Some products such as whippingcream, coffee whiteners, and certain fla-vored products can be processed by high-temperature methods. In general, however,Americans prefer normal pasteurized milk,because it does not have the cooked flavorwhich occurs with the UHT method. Manyobservers, nevertheless, believe that UHT-AP processing and packaging will expand.As new equipment is developed processorswill likely become increasingly interested inincluding UHT-AP methods in the develop-ment and marketing of new products also.

1 Presented at the Sixty-fourth Annual Meetingof the American Dairy Science Association, U~i-versity of Minnesota, Minneapolis, June, 1969.

Processors of dairy products have shownincreased interest in extending shelf life. l~etail-ers and consumers also appreciate the benefitsderived from improved keeping quality of per-ishable food products. A longer shelf life wouldprobably increase the size of the dist ributionarea, reduce the delivery frequency, lower retail-ing costs in stores and vending machines, affordlonger production runs on a given product andreduce product losses.

Although terminology and labeling of dairyproducts given a sterilization treatment andpackaged aseptically has varied, this discussionrefers to the practice of heating a product to140.6 to 148.9 C (285 to 300 F) for 2.5 to8.0 seconds. The method includes packagingthe product in a container which has been givena sterilizing treatment and filled and sealedunder aseptic conditions. Very rapid heatingand cooling is the usual procedure. Packagingtakes place in an atmosphere of steam, sterileair, or gas. The treatment is sometimes referredto as "commercial sterilization." Sometimes theterm "long life" is given these products. Forthis discussion the terms ultra-high temperature(UHT) treatment and aspetic packaging (AP)will be used.

European processors have taken the leader-ship in the development and adoption of UHT-AP methods. Italy leads with about 50 plantsin operation in 1968. Germany reports about12 processing plants and France seven. Eng-land, Sweden, Russia, Australia, Japan, anda few others also have UHT-AP processingoperations. It is estimated that the UnitedStates has aproximately 70 plants using thismethod for dairy products. Most of the plantsin the United States package in metal contain-ers utilizing the Dole system. The majority ofthe foreign operations use the laminated papercontainer to reduce cost. Tetra Pak equipmenthas been employed to the largest extent in theEuropean operations. However, the UnitedStates has made considerable progress in thedevelopment and acceptance of a semirigidpaperboard plastic foil carton.T o l e r a b l e S p o i l a g e

Researchers and processors studying UHT-111

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112 J O U R N A L O F D A I R Y S C I E N C E

A P o p e r a t i o n s f o r s e v e r a l y e a r s h a v e a t t e m p t e dt o d e v e l o p a c c e p t a b l e g u i d e l i n e s f o r t o l e r a b l es p o i la g e . W o r k e r s a t th e N a t i o n a l I n s t i t u t e f o rR e s e a r c h in D a i r y i n g a t R e a d i n g , E n g l a n d ( 2 )h a v e s u g g e s t e d t h a t t h e s p o i l a g e o f o n e c a r t o ni n 1 , 0 0 0 w h e n h e l d a t r o o m t e m p e r a t u r e t w o t ot h r e e w e e k s w o u l d b e a c c e p t a b l e . B e c a u s e o ft h e e x t r e m e l y l o w b a c t e r ia c o u n t s n o r m a l l y p r e v -a l e n t i t i s s o m e w h a t d i f f i c u l t t o e s t a b l i s h t o l -e r a b l e s t a n d a r d s . I n a c t u a l p r a c t i c e v a ri a b l er e s u lt s m a y o c c u r f r o m d a y t o d a y r e l a ti v e tos h e l f l i f e u n t i l e f fe c ti v e o p e r a t i n g p r o c e d u r e sa r e e s t a b l is h e d . T h e r e a r e fe w p u b l i s h e d d a t ao n s p o il a g e f o r U H T - A P d a i r y p ro d u c ts . C o r -r e s p o n d e n c e f r o m A u s t r a l i a in d i c a t e s t h a t p r o d -u c t s f r o m c o m m e r c i a l o p e r a t i o n s w i l l u s u a l l yh a v e u n s a t i s f a c t o r y f l a v o r a f t e r t h r e e m o n th s .R e p o r t s f r o m S w i t z e r l a n d in d i c a t e t h a t u p e r i z e dm i l k h e a t e d t o 1 5 0 C ( 30 2 F ) f o r 2 . 4 s e c o n d sh a s a s h e l f l if e o f a b o u t t h r e e m o n t h s i n f o i lc a r t o n s a n d a b o u t s i x m o n t h s i n m e t a l c a n s .T h e y a l s o r e p o r t s o m e w h a t l o n g e r s h e l f l i f ei n a l u m i n u m c o n t a i n e r s t h a n i n o t h e r t y p e s o fm e t a l c a n s . T h e e x p e r i e n c e o f o n e p l a n t i nS w i t z e r l a n d i n d i c a t e s t h a t t w o t o t h r e e w e e k so f s h e l f l i f e c a n b e o b t a i n e d i n p l a i n p l a s t i c -c o a t e d p a p e r b o a r d c a r t o n s .

A r e p o r t f r o m I t a l y i n d i c a te s t h a t u p e r i z e dm i l k p a c k a g e d i n d o u b l e p l a s t i c a l u m i n u m f o i lT e t r a P a k c o n t a i n e r s h a d a s h e l f l i f e o f 3 0 d a y sw h e n h e l d a t t e m p e r a t u r e s r a n g i n g f r o m 2 0 t o5 5 C ( 6 8 to 1 31 F ) . F o u r s a m p l e s o u t o f 1 ,2 2 8w e r e s p o i l e d a f t e r o n e m o n t h o f s t o r a g e . T h eD a n i s h R e s e a r c h I n s t i t u t e ( 6 ) h a s d o n e e x t e n -s i ve s t u di e s o n th e k e e p i n g q u a l i t y o f U H T -t r e a t e d m i l k p a c k a g e d a s e p t i c a l l y i n v a r i o u st y p e s o f p a c k a g i n g m a t e r i a l s u s i n g a T e t r a P a km a c h i n e . O u t o f 2 9 0 ,0 0 0 c a r t o n s f i ll e d , 1 5 ,0 0 0w e r e s a m p l e d a n d 1 80 o f t h e s a m p l e s w e re f o u n dt o b e n o n s t e r i l e o r v i s i b l y d e f e c t i v e f o l l o w i n g as h o r t p e r i o d o f s t o ra g e . T w o d i f f e r e n t s t e r i l i z e r sw e r e u s ed f o r p r o c e s s i n g t h e p r o d u c t s . D u r i n gs o m e o f t h e t e s t t r i a l s m a l f u n c t i o n i n g o f t h ee q u i p m e n t w a s o b s e r v e d , m a k i n g i t d i f f i c u l t t oa s c e r t a i n t h e s o u r c e o f c o n t a m i n a t i o n .

O t h e r s h a v e a l s o i n d i c a t e d d i f f ic u l t i es i n i s o -l a t i n g t h e s o u r c e o f c o n t a m i n a t i o n o f U H T -t r e a t e d p r o d u c t s . I n c o n s i s t e n c y m a y o c c ur i nm a k i n g t e s t r u n s f r o m o n e d a y t o t h e n e x t w i t hc o m m e r c ia l -s i ze e q u ip m e n t o p e r a t i n g f o r s h o r tp e r i od s . H e d r i e k ( 3 ) s u g g e s t s s a m p l i n g o n c ee v e r y h o u r d u r i n g t h e p r o c e s s i n g a n d f i ll i ngo p e r a t i o n . T h i s p r o c e d u r e w o u l d n o t o n l y p r o -v i d e i n f o r m a t i o n r e g a r d i n g t h e s o u rc e o f c o n -t a m i n a t i o n b u t a l s o v a r i a t i o n s d u r i n g p r o d u c -t i o n .

I n p l a c i n g t h e U H T - A P s y s te m o n s t r ea mi n a c o m m e r c i a l o p e r a t i o n a d e q u a t e t e s t t r i a l sJOURI~AI, OF DAIRY SCIEI~CE VOL. 53, NO. 1

s h o u ld b e m a d e t o e n s u re t h a t t h e e q u i p m e n ti s fu n c t i o n i n g c o r r e c t l y . D i s t r i b u t i o n p r a c t ic e ss h o u l d b e s i m i l a r t o t h o s e o f p r o d u c t s g i v e nu s u a l p a s t e u r i z a t i o n , a t l e a s t d u r i n g t h e i n t r o -d u c t o r y p e r i o d . S a m p l e s s h o u ld b e r e t a i n e di n a d e q u a t e n u m b e r s t o p r o v i d e g u i d e l i n e s o ne q u i p m e n t p e r f o r m a n c e . O n c e r t a in o cc a s io n st h e p r o d u c t c o u l d b e h e ld f o r a p r o x i m a t e l y te nd a y s b e f o r e s h i p p i n g t o m a k e c e r t a i n t h a t a d e -q u a t e s t e r i l i t y h a s b e e n a c h i e v ed .T h e t e m p e r a t u r e d r o p t e s t a s su g g e s t e d b yA s h t o n ( 1 ) m a y b e c o n d u c te d t o d e te r m i n et h e m i n i m u m h e a t t r e a t m e n t n e c e s s a r y to a c h i e v es t e r i l i t y . T h i s t e s t m a y b e u s e f u l i n t h e e a r l ys t a ge s o f p l a c i n g a U t t T s y s t e m in o p e r a t i o n .H e s u g g e s t s o p e r a t i n g t h e u n i t a t 1 4 3. 3 to1 48 .9 C ( 29 0 t o 30 0 F ) i n i t i a l l y a n d d r o p p i n gt h e t e m p e r a t u r e i n f iv e - d e g r e e d e c r e m e n t s t o1 2 6. 7 C ( 2 6 0 F ) . A t e a ch t e m p e r a t u r e , c o l le c t2 5 0 s a m p l e s , i n c u b a t e 1 2 5 o f t h e m a t 2 2 C(71.6 F ) a n d t h e o t h e r h a l f a t 37 C ( 9 8 . 6 F ) .E x a m i n e t h e s a m p l e s h e l d a t 3 7 C d a i l y f o rt e n d a y s a n d e v e r y d a y f o r 1 5 d a y s f o r t h o s eh e l d a t 22 C . S p o i l a g e i n d i c a t e s t h e m i n i m u mp r o c e s s i n g t e m p e r a t u r e , a n d a s a f e t y m a r g i no f 2 .8 C ( 5 F ) s h o u l d b e a d d e d . A g r e e m e n t i sn e e d e d o n t h r e e s e r i e s o f t e s t t r i a l s w i t h te s t sr e p e a t e d e v e r y t h r e e m o nt hs . H e d r i c k ( 3 )f o u n d t h a t i n c u b a t i n g s a m p l e s a t 31 .7 C ( 8 9 F )w a s t h e m o s t c r i t i c a l o f t h e t e m p e r a t u r e s u s e d ,in c lu d in g 2 1 .1 , 3 1 .7 , 3 5 , an d 4 5 C ( 7 0 , 89 , 9 5 ,a n d 1 1 3 F ) .T h e n e e d f o r i n c u b a t i n g s a m p l e s t o d e t e r m i n es h e l f l i f e w a s a l s o e m p h a s i z e d b y S p e c k a n dB u s t a ( 7 ) . T h e y r e p o r t e d t h a t d e t e r m i n i n g b a c -t e r i a c o u n t s u s i n g t h e p l a t e m e t h o d w a s t o oc u m b e r s o m e u n l e s s t h e s a m p l e s w e r e i n c u b a t e d .T e c h n i q u e s u s e d i n d e t e r m i n i n g b a c t e r i a c o u n t so n U H T - A P - t r e a t e d p r o d u c t s a r e v e ry im p o r -t a n t . I t i s s u g g e s t e d t h a t a c l e a n l a b o r a t o r yb e n c h f l oo d e d w i t h s t e r i l e f i l te r e d a i r b e a v a i l -a b l e f o r t h e t e c h n i c i a n .K e e p i n g a n a c c u r a t e s et o f re c o r d s i s ex -t r e m e l y i m p o r t a n t f o r U H T - A P o p e r a t i o n s .E q u i p m e n t p e r f o r n m n c e d a t a , t i m e , t e m p e r a -t u r e c h a rt s , a n d s a m p l i n g i n f o r m a t i o n a r e u s e fu li n e v a l u a t i n g d e f e c t s i n a g i v e n production r u na t a l a t e r t i m e .Q u a l i ty o f R a w M | i k

A d a i r y f a r m e r s u p p l y i n g m i l k t o a p r o c e s s o ru t i l iz i n g U t t T - A P m e t h o d s li k e ly w o u l d n o te x p e r ie n c e a n y r e l a x a t i o n i m p o s e d o n h i m r e l -a t iv e to m a i n t a i n i n g s a n i t a t i o n a n d q u a l i t ys t a n d a r d s . T h e s p o r e c o u nt b e co m e s m o r e i m -p o r t a n t i n e v a l u a t i n g r a w m i l k q u a l i t y f o r t h ist y p e p l a n t . S i n c e h e a t - r e s is t a n t s p o r e s a r e m o s td i f f ic u l t t o k i l l , t h e i r p r e s e n c e i n h i g h n u m b e r s

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w o u l d b e s i g n i f i c a n t. B e c a u s e t e m p e r a t u r e i n -f lu e nc e s s p o r e g e r m i n a t i o n , s t o r i n g U H T - A Pp r o d u c t s a t r e f r i g e r a t e d t e m p e r a t u r e s i s r e c -o m m e n d e d f o r e x t e n d i n g k e e p i n g q u a l i ty , i n -c l u d i n g t h e p r e s e r v a t i o n o f d e s i r ab l e p h y s i c a lc h a r a c t e r i s t i c s a n d f l a v o r s t a b i l i t y .S t u d i e s u s i n g t h e B a c t o f u g e 2 f o r s p o r e r e -m o v a l b e f o re U H T t r e a t m e n t s h o w e d no s ig n i fi -c a n t e f fe c t w h e n p r o c e s s i n g h i g h - q u a l i t y r a wm i l k. P e r h a p s w i t h v e r y p o o r q u a l i t y r a w m i l k,c o n t a i n i n g a h i g h s p o r e c o u n t , s o m e s i g n i f i c a n ti m p r o v e m e n t w o u l d b e d e t e c ta b l e w h e n u t i l i z i n gt h e B a c t o f u g e b e f o r e t h e U H T t r e a t m e n t .Asept ic Packages and Equi ,pment

T h e c h o ic e o f a p a c k a g e f o r p a c k a g i n g U H T -A P G r a d e A d a i r y p r o d u c ts w o u l d de p e n d ons e v e r a l f a c t o r s i n c l u d i n g c o s t , s a l e s a p p e a l , c o n -s u m e r a c c e p t a n c e , w e i g h t , s p a c e r e q u i r e d , s h a p e ,p r o t e c t i o n a g a i n s t c o n t a m i n a t i o n , p r o d u c t c h a r -a c t e r i s ti c s , n e e d f o r r e t u r n a b l e c a s e s , e t c. I f ap r o c e s s o r e x p a n d s h i s m a r k e t i n g a r e a o v e r m a n ys t a t e s , i t w o u l d b e a d v a n t a g e o u s t o u s e a o n e -w a y o v e r w r a p o r n o n r e t u r n a b l e c a s e f o r t h ep a c k a g e s . C o n t a i n e r s s h i p p e d i n n o n r e t u r n -a b l e c a s e s w o u l d h a v e a m a j o r a d v a n t a g e i nd i s t r i b u t i o n co s t s. M o s t p r o c e s s o r s s h i p p i n gg r e a t d i s ta n c e s p l a c e p a c k a g e s in n o n r e t u r n a b l ec o r r u g a t e d c a r d b o a r d o r s o m e t y p e o f o v e r -w r a p . C h o i ce s a v a i l a b l e t o th e p r o c e s s o r f o ra s e p t i c p a c k a g i n g o p e r a t i o n s i n cl u d e m e t a l c a n s,g l a s s c o n t a i n e rs , s e m i r i g i d p l a s t ic p a p e r f o i lc o n t a i n e r s , f l e x i b l e p l a s t i c c o n t a i n e r s , p l a s t i cf o r m - f i l l - s e a l c o n t a i n e r s , a n d b l o w - m o l d e d p l a s -t i c b o t tl e s . M e t a l c a n s f i ll e d b y t h e D o l e p r o c e s sa r e t h e m o s t e o m u m n i n u s e i n t h e U n i t e d S t a t e s .T h i s e q u i p m e n t h a s p r o v e n s a t i s f a c t o r y i n c o m -m e r c i a l p r o d u c t i o n f o r s e v e r a l p r o d u c t s . S u p e r -h e a t e d s t e a m i s t h e s t e r i l i z i n g a g e n t f o r t h e c a n .F i l l i n g o c c u rs i n a s t e a m c h a m b e r a t a t m o -s p h e r i c p r e s s u r e w h i c h m a i n t a i n s t h e s t e r i l ee n v i r o n m e n t .C o n s i d e r a b le w o r k h a s b e en d o n e a t t h e N a -t i o n a l In s t i t u t e o f R e s e a r ch f o r D a i r y i n g i nE n g l a n d o n f i l li n g g l a s s c o n t a i n e r s a s e p t i c a l l y .S o m e n e w a n d i m p r o v e d m o d e l s o f g l a s s f i l l e r sw e r e d i s p l a y e d a t t h e E u r o p e a n D a i r y S h o w i nJ u n e , ] 9 6 9 .F o r m - f i l l - s e a l e q u i p m e n t h a s b e e n m o d i f ie da n d w i ll p r o b a b l y b e u s e d m o r e in t h e d a i r y a n df o o d i n d u s t r y . A c c e p t a b i l i t y h a s b e e n d em o n -s t r a t e d o n s m a l l e r -s i z e e o n t a i n e r s s u c h a sc r e a m e r s . C u r r e n t m o d e l s f o r m - f i l l a n d s e a ln i n e o r 1 6 c r e a m e r s p e r c y c le . T y p i c a l o f a l la s e p t i c u n i t s , t h e m a c h i n e i s c a r e f u l l y s h r o u d e d

2 C en t r i f u g a l mach in e d es ig n ed to r emo v e mic r o -o r g a n i s m s f r o m m i l k .

t o a v o i d c o n t a m i n a t i o n o f t h e t h e r m o p l a s t i cc o n t a i n e r d u r i n g f o r m i n g , f l l i n g , a n d s e a l in g .F o r e c on o m ic a n d o t h e r r ea s o n s c o n s i d e r a b lee m p h a s i s h a s b e en p l a c e d o n t h e d e v e l o p m e n to f l a m i n a t e s o f p a p e r b o a r d , p l a s t i c , a n d a l u m i -n u m f o i l. T h i s m a t e r i a l i s b e i n g f o r m e d i nr e c t a n g u l a r a s w e l l a s i n t h e m o r e c o m m o nt e t r a h e d r o n s h ap e . E u r o p e a n - m a d e e q u ip m e n tg e n e r a l l y u t i l iz e s a l a r g e r o l l o f t h e l a m i n a t e ,w h i c h i s f o r m e d i n t o a t u b e a n d f i ll e d w i t h o u te n t r a p p i n g a i r a n d s e a l ed w i t h h e a t e d j a w s .P a c k a g e s k n o w n as T e t r a B r i k a n d S e l f P a c ka r e f o r m e d in t o r e c t a n g u l a r sh a p e s . I t h a s b e e nd e m o n s t r a t e d t h a t t h e r e c t a n g u l a r p a c k a g e sm a y b e a c c u m u l a t e d a n d e n c l o s e d w i t h a n o v e r -w r a p p e r m i t t i n g s t o r a g e t o a s h i g h a s fi vel a y e r s .

T h e t y p i c a l 5 - p l y l a m i n a t e m a t e r i a l o f as e i a i r i g id p la s t i c f o i l c o n t a i n e r f r o m t h e i n t e r i o rs u r f a c e o u t w a r d w o u l d b e p o l y e t h y l e n e , a l u m i -n u m f o i l, p o l y e t h y le n e , p a p e r b o a r d , a n d p o l y -e t h y le n e . T h e P u r e P a k c a r t o n is a v a i l a b l e w i t ht h e c u t e d g e s e a l e d t o b e t t e r c o n t r o l v a p o r t r a n s -m i s s i o n . I n j e c t i n g e t h y l e n e o x i d e g a s i n t o t h ep a p e r s h i p p i n g c a r t o n a t a c o n c e n tr a t i o n o fa b o u t 3 2 0 p p m h e l p s e n s u r e v i r t u a l l y s t e r il ec a r t o n b l a n k s t o t h e u se r . T h e e t h y l e n e o x i d eg r a d u a l l y d i s s i p a te s d u r i n g s h i p m e n t o r s t o r a g eo v e r a p e r i o d o f o n e w e e k to a b o u t 1 p p m .V a r i o u s c h e m i c a l s h a v e b e e n u s e d t o s a n i t i z et h e p r o d u c t c o n t a c t s u r f a c e o f t h e c o n t a i n e r .C h l o r i n e h a s b e e n u s e d ; h o w e v e r , h y d r o g e np e r o x i d e s e e m s t o b e t h e f a v o r e d s a n i t i z e r a tt h e p r e s e n t t im e . H y d r o g e n p e r o x i d e is c o n -v e r t e d t o w a t e r a n d o x y g e n , r e s u l t i n g i n a ne f fe c t iv e s a n i t i z e r . D u r i n g o p e r a t i o n t h e p a c k -a g e m a t e r i a l i s d r a w n t h r o u g h a h y d r o g e n p e r -o x i d e b a t h a t 8 0 C ( 1 76 F ) o r t h e s a n i t i z e r m a yb e s p r a y e d o r f o g g e d o n t h e c r i t i c a l s u r f ac e s .T h e p a c k a g e m a t e r i a l i s e x p o s e d t o t e m p e r a -t u r e s o f a p p r o x i m a t e l y 2 32 .2 t o 3 1 5. 6 C ( 45 0 t o

6 0 0 F ) , w h i c h a c h i e v e s t h e s t e r i l i z i n g e ff e c t a n dd i s s i p a t e s a n y h y d r o g e n p e r o x i d e p r e s e n t . T h eP u r e P a k m a c h i n e e m p l o y s a f o g g i n g s y s t e m toi n j e c t h y d r o g e n p e r o x i d e in t o t h e c a r t o n a t ar a t e o f a p p r o x i m a t e l y 0.1 t o 0 .2 m l p e r q u a r tc a r t o n . E x c e s s h y d r o g e n p e r o x i d e i s c o n d u c t e df r o m t h e m a c h in e w i th a n e x p e l l e r f a n f o r o p e r -a t o r c o m f o r t .A t t e m p t i n g t o c o n v e r t m o s t r e g u l a r f il le rsi n th e U n i t e d S t a t e s t o a s e p t i c u n i t s i n t h e f ie l di s g e n e r a l l y n o t r e c o m m e n d e d .

Blow -M old Plastic Bott lesI n G e r m a n y , a u n i q u e m e t h o d o f b l o w m o l d -i n g p l a s t i c c o n t a i n e r s a n d f i ll i n g t h e m a s e p t i c a l l yw h i l e s t i ll i n t h e m o l d h a s b e e n d e v e l o p e d . R e l a -

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1 1 4 J O U R N A L O F D A I R Y S C I E N C Et i v e l y l o w c a p a c i t y m a c h i n e s a r e n o w a v a i l a b l ei n t h e U n i t e d S t a t e s , w i t h l a r g e r m a c h i n e sb e i n g d e si g n e d . B e c a u s e t h e p l a s t i c m a t e r i a lm u s t b e h e a t e d t o a b o u t 23 2 .2 C ( 45 0 F ) f o rb l o w m o l d i n g , it i s s t e r il i z e d , a n i n h e r e n t a d v a n -t a g e o f t h e u n it . M a i n t a i n i n g a s t e r il e e nv i r o n -m e n t a r o u n d t h e f i l li n g n o z z l e to a v o i d c o n -t a m i n a t i o n d u r i n g f i ll i n g a n d t o p s e a l i n g o f t h eb l o w - m o l d e d c o n t a i n e r i s o b v i o u s l y s t i l l n e c e s -s a r y . S o m e o f t h e b l o w - m o l d a s e p t i c u n i t s a r eb e i n g t e s t e d i n t h e U n i t e d S t a t e s . T h e c a p a c i t yo f t h e u n i t d e p e n d s , i n p a r t , u p o n t h e s i z e o ft h e c o n t a i n e r a n d t h e n u m b e r o f b l o w - m o l dh e a d s o n t h e m a c h i n e . Q u a r t - s i z e p a c k a g e s n o r -r e a l l y c a n b e f o r m e d a t a r a t e o f s i x o r s e v e np e r m i n u t e . A b l o w - m o l d m a c h i n e h a s a ls o b e e nd e v e l o p e d i n S w i t z e r l a n d .

SanitationM o s t o f t h e p r e s e n t m o d e l s o f a s e p t i c f i ll e r sc a n n o t b e c o m p l e t e l y c l e a n e d i n p l a c e . G e n e r -a l l y , s o m e d i s m a n t l i n g is n e c e s s a r y a n d p a r t s a r ec l e a n e d i n a w a s h v a t . O n e o f t h e n m n u f a c t u r -e r s o f f o r m - f il l , s e a l e q u i p m e n t s u g g e s t s a n i n t e r -e s t i n g m e t h o d o f a s s e m b l i n g t h e c r i t i c a l fi l le rp a r t s t o e n s u r e s t e r i l i t y . T h e p r o c e d u r e b a s i -c a l l y i s a s f o l l o w s :1 . B e f o r e a s s e m b l i n g , p l a c e t h e p a r t s i n b o il -i n g w a t e r f o r 1 0 m i n u t e s .2 . W e a r p l a s t i c g l o v es w h en h a n d l i n g t h ep a r t s . R i n s e t h e f i l le r b o w l w i t h 1 00 p p mo f c h l o r in e , fl o od w i t h h o t w a t e r , a n d a g a i nr i n s e w i t h 1 00 p p m c h l o r i n e s o l u t io n .3 . S t e a m t h e u n i t a t 5 t o 6 p s i s o t h e t e m -p e r a t u r e r e a c h e s a t l e a s t 1 0 4 .4 C ( 2 20 F ) ,a n d m a i n t a i n u n t i l s t e r i l i t y i s a c h ie v e d .A p p l y i n g h e a t u s u a l l y a s s t e a m i s t h e m o s tc o m m o n m e t h o d f o r s t e r i l i z i n g l in e s , v e ss e ls ,a n d f il l in g e q u i p m e n t . G a s k e t s a n d o t h e r p a r t s

m u s t h a v e t h e a b i l i t y t o w i t h s t a n d s t e r i l i z i n gt e m p e r a t u r e s . S i l i c o n e i s o n e o f t h e m a t e r i a l sf o u n d t o b e s a t i s f a c t o r y . T h e r m o c o u p l e s a r eu s e f u l f o r i n d i c a t i n g t h e t e m p e r a t u r e o f t h es h r o u d i n g o r b l o c k s u r r o u n d i n g t h e f i ll i n g c h a m -b e r s . I t i s i m p o r t a n t t o o b s e rv e t h e m a x i m u mt e m p e r a t u r e r e a c he d d u r i n g s t e r i l i z i n g p r o c e -d u r e s s o t h a t c o r r e c t i o n s c a n b e m a d e i f n e c e s -s a r y .M o s t a s e p t i c f i ll e rs a r e d e s i g n e d t o c o n t r o lt h e f i l li n g e n v i r o n m e n t a r o u n d t h e p a c k a g e , p r o -v i d i n g e f fe c ti v e p r o t e c t i o n a g a i n s t c o n t a m i n a t i n gm i c r o o r g a n i s m s . T h e s y s t e m s e m p l o y s t e r i l i z e da i r , o b t a i n e d e i t h e r b y h e a t i n g o r w i t h h i g h -e f fi ci e nc y f i lt e r s. T h e a r e a a r o u n d t h e c a r t o ni s g i v e n t h e m o s t p r o t e c t i o n ; h o w e v e r , i n s o m eo p e r a t i o n s t h e e n t i r e f i ll i n g r o o m i s p r o v i d e dJOURNAL OF DAIRY SCIENCE VOL. 53, NO. 1

w i t h c a r e f u l l y f i l te r e d a i r w h i c h r e s u l t s i n t h es o - c a l l e d " c l e a n r o o m . "

CostsC o s t s i n v o l v ed i n s t e r i l i z in g a n d a s e p t i c p a c k -a g i n g u t i l i z in g t h e P u r e P a k c a r t o n w e r e s t u d -i e d b y H o r a n a n d I- I ed r i ck ( 5 ) . E s t i m a t e dp r o c e s s i n g a n d s t e r i l iz a t i o n co s ts f o r m i l k b e f o r ep a c k a g i n g a m o u n t e d t o 0 . 7 6 c e n t p e r q u a r t .L a b o r , u t i l it i e s , d e p r e c i a t i o n , t a x e s , i n t e r e s t , a n dm i s c e l l a n e o u s c o s t s w e r e i n c l u d e d . T h e a s e p t i cp a c k a g i n g c o s t w a s 3 .7 1 c e n t s, re s u l t i n g i n at o t a l p l a n t c h a r g e o f 4. 47 c e n ts p e r q u a r t . W i t hr a w m i l k v a l u e d a t $ 6 .2 5 p e r h u n d r e d w e i g h t a n d3 .1 5 c e n ts p e r q u a r t e s t i m a t e d f o r d e l i v e r y r e -s u l t s i n a t o t a l o f 2 1 .0 2 c e n ts p e r q u a r t . T h e

p a c k a g e i t s e lf is a b o u t t w i ce t h a t o f a s t a n d a r dp l a s t i c p a p e r b o a r d c o n t a i n e r b e c a u s e o f t h ei n c o r p o r a t i o n o f a l u m i n u m f o i l a n d a n a d d i -t i o n a l l a y e r o f p o l y e t h y l e n e .

Dis t r ibu t ionT h e q u a l i t y o f U H T - A P p r o d u c t s i s e x t e n d e dby re f r ig e ra t ion tempera tures. S tud ies con-ducted b y H e r r e i d ( 4 ) i n d ic a t e t h a t U H T m i l kt r e a t e d a t 1 46 .1 t o 1 4 8 .9 C ( 2 9 5 t o 3 0 0 F ) h a da f l a v o r s c o r e i m m e d i a t e l y a f t e r p r o c e s s i n g o f

a b o u t 3 7 .5 t o 3 8 . T h i s m i l k w h e n h e l d a t 4 . 4 C( 4 0 F ) f o r o n e w e e k h a d a s c o r e o f 3 9 , w h e r e a sw h e n h e l d a t 21 .1 C ( 7 0 F ) t h e s c o r e d r o p p e dt o 3 7 a n d d e c l i n e d t o 3 6 w h e n h e l d a t 3 7 .8 C( 10 0 F ) . T h e d e v el o p m e n t o f o th e r d e f e c tsr e l a t e d t o t h e p h y s i c a l c h a r a c t e r i s t i c s o f t h ep r o d u c t i s a ls o a f fe c te d b y t e m p e r a t u r e . H i g h e rt e m p e r a t u r e s d u r i n g d i s t r i b u t i o n a n d s t o r a g ea c c e l e r a t e d e t e r i o r a t i o n , e . g . , t h e f o r m a t i o n o fa f a t l a y e r o n t h e p r o d u c t , d i s c o l o r a t i o n , a n dg e l a ti o n . H a n d l i n g p r a c t i c e s s i m i l a r t o t ho s eu s e d f o r n o r m a l p a s t e u r i z e d p r o d u c t s a r e s u g -g e s te d f o r U H T - A P p r o d u ct s . R e f r i g e r a t io ns h o u l d b e u s e d a t t h e p r o c e s s i n g p l a n t , i n m a r -k e t i n g c h an n e l s , a n d i n th e h o m e . T h e a d v a n -t a ge s o f U H T - A P a r e t h a t t h e p r o d u c t h a s t h ek e e p i n g q u a l i t y to w i t h s t a n d m o r e h e a t sh o c k ,p e r m i t t i n g t h e p r o c e s s o r t o d i s t r i b u t e o v e r aw i d e r a r e a a n d w i t h f e w e r r e t u r n e d p r o d u c t s .

References( 1 ) Ash to n , T . R . 1 9 6 6 . C o n t r o l me th o d s ap p l i e dt o a s e p t i c m i l k p r o d u c t io n . D a i r y I n d u s t r y ,

31: 6.( 2 ) B u r t o n , H . 1 9 6 5 . U l t r a h ig h t e m p e r a t u r ep r o c e s s i n g a n d a s e p t i c p a c k a g i n g i n t h ed a i r y i n d u s t r y - - I t s b a s i c p r i n c i p l e s a n ddevelopm ents . J . Soc . D air y Technol . , 18 : 2 .

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(3) Hedrick, T. I. 1969. Personal communica-tion. Michigan State University, East Lan-sing.(4) Herreid, E. O. 1965. New facts concerningthe physical, chemical and storage stabilityof sterilized milk and cream. Proc. MilkInd. Found. 58th Ann. Meet., Montreal,Canada.(5) Horan, J., and T. I. Hedrick. 1968. Costs

of milk sterilization and aseptic packagingin paper cartons. Amer. Dairy Rev., 30: 7.(6) Mann, E. J. 1969. Aseptic packaging ofmilk and milk products. Dairy Indus try,34: 1.(7) Speck, M. L., and F. F. Busta . 1968. Steri-lization and aseptic packaging of milkproducts--microbiologlcal trends. J. Dai rySci., 51 : 1146.

A S S O C I A T I O N A F F A I R S

Reappointment of Editor ial Board MembersThe new policy of Journal Management

changed appoi ntment s of the Editori al Boardmembershi p to a 3-year term with one re-newal for a maximum additional 3 years, ifthe Journal Management Committee and theindi vidu al both agree. The following havewillingly agreed to a reap poin tmen t:Dr. C. C. Baleh, NIRD, Eng lan dDr. R, E. Brown, Univ. of IllinoisDr. J. R. Brunner, MSU, MichiganDr. Olaf Claesson, IHU OV, SwedenDr. G. Loftus Hills, CSIRO, AustraliaDr. 0. W. Kaufm ann , NCUIH, OhioDr. F. A. Kummerow, Univ. of IllinoisDr. W. A. MeGillivray, DRI, New ZealandDr. T. A. J. Payens, NIZO, NetherlandsDr. E. W. Swanson, Univ. of TennesseeDr. T. Tsugo, Univ. of Tokyo, Jap an

The Editors of the Journal of Dairy Scienceand other members of the Journal Manage-ment Committee are sincerely gratefu l for theexcellent review service these i ndiv idu als haveperformed. Each of these men has given ex-cellent service on the Editorial Board for atleast five years and has consented to servefor anot her term of 1 to 3 years. Thei r re-views have contributed to the internationallyrecognized quality of the Journal of DairyScience publications. ADSA members are en-couraged to personally express appreciationfor the dedicated assistance of these Boardmembers.

T. I. Hedriek, GhairmanJournal Management Committee

JOURNAL OF DAIRY SCI~NCB ~rOL. 53, NO. 1