270. HOT C U T T N G AND P R O C E S S N G O F P O R K R. W. MANDGO The p r o c e s s i n g of pork products t o a f i n i s h e d form p r i o r t o i n i t i a l c h i l l i n g appears t o have many advantages over t h e p r e s e n t techniques u t i l i z e d i n pork processing. Present i n d u s t r y methods r e q u i r e t h e products t o remain i n t h e packinghouse from two days t o two weeks depending on t h e v a r i o u s steps i n f a b r i c a t i o n. Accelerated pork processi n g methods could be used t o reduce t o a minimum t h e c o s t l y f a b r i c a t i o n s t e p s involved w i t h c a r c a s s c h i l l i n g, curing, smoking, and f i n a l c h i l l i n g found i n conventional processing. The completion of a l l or some o f t h e f a b r i c a t i o n s t e p s p r i o r t o t h e i n i t i a l c h i l l i n g o f t h e pork product has been d e s c r i b e d a s "Hot Processing", "PreChill Processing", "Processing P r i o r t o Rigor Nortis", and "Accelerated Pork Processing". All a r e, i n f a c t, attempts t o a c c e l e r a t e t h e i n p l a n t p r o c e s s i n g s t e p s and r e s u l t i n s i g n i f i c a n t proce s s i n g time r e d u c t i o n s. The flow c h a r t f o r t h e f r e s h c u t s i s shown i n f i g u r e 1. S l a u g h t e r i n g and p r e p a r a t i o n of t h e c a r c a s s f o r t h e c o o l e r i s not changed i n t h e a c c e l e r a t e d pork p r o c e s s i n g systems. These "new" systems s t a r t a t t h e p o i n t where t h e c a r c a s s would normally l e a v e t h e s l a u g h t e r f l o o r, The time elapsed from t h e completion of s l a u g h t e r i s shown f o r b o t h t h e conventional and t h e a c c e l e r a t e d p r o c e s s i n g systems. C h i l l i n g i s omitted i n t h e a c c e l e r a t e d system. One hour o f time i s allowed t o t h e p o i n t where e f f e c t i v e c h i l l i n g would t a k e p l a c e. Thus 25 h r would have elapsed t o t h e p o i n t where c u t t i n g of t h e c a r c a s s t a k e s p l a c e i n t h e conv e n t i o n a l system as compared t o one hour f o r t h e a c c e l e r a t e d system. C h i l l i n g following c u t t i n g i s omitted i n t h e conventional system and r e q u i r e s approximately two hours i n t h e c a s e of f r e s h pork c u t s i n t h e a c c e l e r a t e d system. Thus, t h e f r e s h pork products a r e ready f o r shipment i n about 25 hours i n t h e case of t h e conventional system and about four hours i n t h e r a p i d system. A s i m i l a r f i g u r e ( f i g. 2 ) i s shown t o i l l u s t r a t e t h e flow p a t t e r n f o r t h e cured c u t s. Again zero time i s considered t o be t h e p o i n t where t h e c a r c a s s e s l e a v e t h e s l a u g h t e r floor. The c h i l l i n g and c u t t i n g steps a r e t h e same as f o r t h e f r e s h c u t s, Fumping of t h e c u r e i s s t a r t e d a t about 2 6 hours i n t h e conventional c u t s and two hours i n t h e r a p i d system. Three days c u r i n g t i m e was allowed f o r t h e convent i o n a l system, while one hour was allowed f o r t h e r a p i d system p r i o r t o p l a c i n g t h e meat i n t o t h e smokehouses. A smoking time of 1 0 hours was used f o r both systems. C h i l l i n g a f t e r srcoking added 2 4 hours t o t h e conventional, and two hours was used i n t h e a c c e l e r a t e d system. Thus, time e l a p s e t o e a r l i e s t shipment was 132 hours f o r conventional processi n g and 15 hours f o r t h e a c c e l e r a t e d methods. Many v a r i a t i o n s on t h e s e flow c h a r t s can be found; t h e s e s e r v e only a s examples.
271. The effect of the processing method on the yield and quality factors of ham was reported by Mandigo and Henrickson (1966). They found no significant differences in the yield of the finished ham. Lean, fat and bone components removed from the boneless, pressed hams were not found to be significantly different. Some difficulty in removal of the ham was indicated and the removal of fat was reported to be easier from hotprocessed hams than from those processed cold. WarnerBrat zler shear values were determined on 3/4inch cores taken from 1/2inch slices (Mandigo and Henrickson, 1966). The differences between hot and coldprocessed hams in tenderness were nonsignificant, Fig. 1. Flm Diagram for Fresh Cuts FRESH C U T S C O N V E N T O N A L A C C E L E R A T E D T M E H R /SLAUGHTER; 0 0 is L A U G H T E R : j ' C H L L N G 11 C U T T N G 25 0 ; 11 C U T T N G SHPMENT i25 i, ~ C H L L N G ~ S H P M E N T 1 These findings are further supported by Davidson et al. (n Print) who found no significant difference in the shear values of semimembranosus and biceps femoris muscle from hot and conventional processed hams. Percent moisture of the ham samples was determined by the AOAC (1950) methods. No significant differences were found in moisture content (Mandigo and Henrickson, 1966). Davidson et al. (n Print) were unable to show differences in the expressible moisture ratios of cured and smoked semimemkranosus and biceps femoris muscles from hot and conventionally processed hams. Weiner (1964) found hams cut and processed within one hour of bleeding to have significantly lower drip losses, cooking losses than the controls. He found significantly lower shear values in the treated hams. Davidson et al. (n Print) found no significant differences in processing weights, processing shrinkage weights, and percent shrink of cured and smoked hams from hot and conventionally processed carcasses. Weiner et al. (1966) reported no significant differences in curing yield between hams pumped within 1 hour postmortem and control hams.
272. Fig. 2. Flow Diagram f o r Cured Cuts C U R E D C 0 N V E N T O N A L SLAUGHTER^ o T M E CUTS H R A C C E L E R A T E D 0 / S L A U G H T E R / 0 / C U T T N G 125 1 2 SMOKNG 98! 3 / S M O K N G 13 j C H L L N G _ 15 / S H P M E N T ~ An e v a l u a t i o n of t h e f r e s h pork l o i n processed by hot p r o c e s s i n g methods was r e p o r t e d by Moore et a l. (1966). Fourinch s e c t i o n s were f r o z e n from pork l o i n s s t a r t i n g between t h e 1 0 t h and 1 1 t h r i b s and extending p o s t e r i o r l y. Following f r e e z i n g, t h e l o i n s were thawed and thaw l o s s determined. The amount of thaw l o s s was found t o be s i g n i f i c a n t ( P <.Ol) f o r v a r i a t i o n among animals, b u t no s i g n i f i c a n t d i f f e r e n c e s were found between t h e methods of processing. Moisture l o s s, r e s i d u a l moisture, and shear v a l u e s were determined. No s i g n i f i c a n t d i f f e r e n c e s f o r any of t h e s e measures were found for method o f c u t t i n g ( h o t vs. cold p r o c e s s i n g ), Weiner et a l. (1966) s t u d i e d t h e e f f e c t of method of processing. Muscles from l o i n s removed p r i o r t o r i g o r mortis and c h i l l e d were s i g n i f i c a n t l y more t e n d e r t h a n c o n t r o l s, while l o i n s removed and f r o z e n had s i g n i f i c a n t l y higher s h e a r values. Freezing temperatures were et a l. (1966), b u t complete f r e e z i n g d i d not occur, employed b y Moore o n l y a s u r f a c e f r e e z i n g. Under t h e s e c o n d i t i o n s, no s i g n i f i c a n t d i f f e r ences i n s h e a r v a l u e were observed. Mandigo and Henrickson ( n P r i n t ) r e p o r t e d t h e e f f e c t o f p r o c e s s i n g method on bacon and i n d i c a t e d t h a t method o f p r o c e s s i n g had l i t t l e e f f e c t on t h e y i e l d of bacon. S i g n i f i c a n t d i f f e r e n c e s i n t h e l e n g t h and width measurements were noted. Commercial p r e s s i n g of t h e slabs reduced t h e d i f f e r e n c e s b u t d i d not completely compensate f o r method of processing. The d i f f e r e n c e s can be c h a r a c t e r i z e d by wider and
273. s h o r t e r s l a b s found f o r t h e p r e c h i l l processed bacon. These d i f f e r ences were a t t r i b u t e d t o t h e s t r e t c h i n g e f f e c t which normally occurs i n t h e c h i l l i n g of t h e i n t a c t c a r c a s s. No s i g n i f i c a n t d i f f e r e n c e was found i n t h e number o f slices obtained from t h e bacon processed hot or cold. The weight of s l i c e d bacon, bacon t r i m and processing s h r i n k were a l s o found t o be nons i g n i f i c a n t l y d i f f e r e n t f o r t h e two processing treatments. Barbe e t a l. ( n P r i n t ) found t h e incidence of a e r o b i c bacteria i n r a p i d processed ham t o be comparable t o t h a t i n t h e con v e n t i o n a l l y processed product. Greater r e d u c t i o n i n t o t a l b a c t e r i a numbers were obtained w i t h t h e r a p i d processing technique. They found 68% of t h e h o t processed hams w i t h no c o l o n i e s o r i n s i g n i f i c a n t numbers p e r gram as compared w i t h 53% f o r t h e conventionally processed hams based on i n t e r n a l samples. C l o s t r i d i a were i s o l a t e d from t h e t i s s u e of f o u r hams out of t h e t o t a l 38 surveyed, a l l were negative f o r Clostridium p e r f r i n g e n s. The l e v e l of contamination by anaerobic organisms was found t o b e less t h a n 10 p e r gram of t i s s u e. e t _a l. ( n P r i n t ) reported higher mesophilic Davidson counts from hot processed pork sausage. They r e p o r t e d t h a t t h e i r f i n d i n g s tend t o a g r e e w i t h t h o s e r e p o r t e d by Fulliam and Kelly (1965) who worked w i t h hams. Psychrophilic counts a f t e r 1520 days i n s t o r age showed s i g n i f i c a n t l y g r e a t e r counts. Coliform counts were e r r a t i c and g e n e r a l l y low i n t h e i r study, which i s i n agreement w i t h t h e f i n d et al. ( n Print). i n g s of Barbe The moisture, p r o t e i n, e t h e r e x t r a c t, ash and s a l t c o n t e n t s of sausage from hot and conventionally processed c a r c a s s e s were not s i g n i f i c a n t l y d i f e r e n t i n t h e work b y Davidson et a i. ( n Print). odine numbers were determined t o measure t h e degree of u n s a t u r a t i o n of t h e pork sausage. They found no d i f f e r e n c e s a t t r i b u t a b l e t o method of processing. S i g n i f i c a n t l y g r e a t e r ( P.Ol) peroxide v a l u e s were found i n conventionally processed sausage a f t e r 10 and 20 days t h a n i n t h e sausage from h o t processed c a r c a s s e s. < Mandigo (1967) reported t h e r e s u l t s of a c o l o r s t a b i l i t y study on boneless, fullycooked, pressed hams. He found no s i g n i f i c a n t d i f f e r ence i n t h e amount of e x t r a c t a b l e nitrosopigments when evaluated 24 h r a f t e r t h e completion of processing. Ground samples were exposed t o 200 f t c of f l u o r e s c e n t l i g h t f o r v a r i o u s p e r i o d s of t i m e ( 0, 30 min, 1, 2, 3, 4, 5, 6, and 24 h r ). S i g n i f i c a n t l y more nitrosopigments remained a f t e r 30 min exposure t o l i g h t i n t h e case of t h e p r e c h i l l processed ham. No s i g n i f i c a n t d i f f e r e n c e s were observed i n t h e one through 24 hour exposures. n a l l c a s e s, t h e a c c e l e r a t e d processed hams contained more nitrosopigments. Nitrosopigments were found t o b e 54 ppm a t zero t i m e and 5ppm a t 24 hours. Current s t a t u s o f work a t t h e U n i v e r s i t y of Nebraska involves design, development and t e s t i n g of a prototype system t o be evaluated under packinghouse c o n d i t i o n s. Following t e s t i n g and e v a l u a t i o n under
274. laboratory conditions, the system will be placed in a commercial packing plant and evaluated under their conditions with packinghouse personnel operating the system. Work in this phase is being supported under a Cooperative Agreement with the Transportation and Facilities Research Division of the USDAARS. Personnel from the Animal Science and Agricultural Engineering Departments at the University of Nebraska are involved in the current phase. References AOAC. 1950. Official Methods of Analysis. 7th ed. Assoc. Offic. Agr. Chemists, Washington, D.C. Barba, C. D., R. W. Mandigo and R. L. Henrickson. (n Print). Bacterial Flora Associated with RapidProcessed Ham. J, Food Sci. Davidson, W. D., R. L. Cliplef, R. J. Meade and L. E. Hanson. (n Print). Effects of PostMortem Processing Treatment on Selected Characteristics of Ham and Fresh Pork Sausage. Food Technol. Miindigo, R. W. and R. L. Henrickson. 1966. nfluence of HotProcessing Pork Carcasses on Cured Ham. Food Technol. 20(4):186. Mandigo, R. W. 1967. The nfluence of PreChill Processing on Pork Products. Ph. D. Thesis, Oklahoma State University. Mandigo, R. W. and R. L. Henrickson. (n Print). The nfluence of PreChill Processing Techniques on Bacon, Food Technol. Moore, R. E,, R. W. Mandigo and R. L. Henrickson. 1966. The Effect of Cutting, Chilling, and Cooking Method on the Quality of Pork Loin. Food Technol. 20( 7):107. Pulliam, J. D. and D. C. Kelly, 1965. Bacteriological Comparisons of Hot Processed and Normally Processed Hams. J. Milk and Food Technol. 28:285. Weiner, P. D. 1964. The Effect of Processing Pork Carcasses Prior to Rigor Mortis Upon Muscle and Fat Quality. M. S. Thesis, Kansas State University. Weiner, P. D., D, H. Kropf, D. L. Mackintosh, and B. A. Koch. 1966. Effect on Muscle Quality of Processing Pork Carcasses within One Hour PostMortem. Food Technol. 20:541. ###########