01994Applied Poultry Science. Inc STABILIZATION PROCESSING OF POULTRY BY-PRODUCTS WASTE AND POULTRY AND CARCASSES THROUGHLACTICACID FERMENTATION' TIANDE CAI and OSCAR C. PANCORB02 Department of Food Science and Technology, University of Georgia, Athens, G A 30602 Phone: (706) 542-1001 FAX: (706) 542-7472 WILLIAM C. MERKA Department of Poultry Science, University of Georgia,Athens, G A 30602 JEAN E. SANDER Department of Avian Medicine, University of Georgia, Athens, G A 30602 HAROLD M.BARNHAR? f Department of Food Science and Technology, University o Georgia, Athens, G A 30602 Primary Audience: Poultry Producers, Flock Supervisors, Rendering Managers, Processing Managers MMARY Laboratory and field experiments were conducted to evaluate lactic acid fer th industrial carbohydrate by-products as fermentation subs r processing offal, blood, and dissolved air flotationwastewater carcasses. Additions of 15% brewer's solubles, 15% dry mol molasses, 6% cane sugar,6%whey product, or higher proportion ge (pHS4.2) at 30°C or 37°C o 15% or less putrefied. Reduced te a commercial silage culture of lactic acid rmentation. Offal mixed with DAF sludge at 12% and 24% was alone. Fermentation with 15% brewer's solubles was the d for preserving both poultry processing by-products and waste for subsequent nutrient recovery. cts, carcasses, fermentation, lactic a 1994J. Appl. Poul 1 A portion of this paper was presented at the 1992 Food Industry Environmental Conference, Georgia Tech Research Institute, Atlanta, GA. 2 Present address: Division of Environmental Analysis, Senator William X. Wall Experiment Station, Massachusetts Department of Environmental Protection, 37 Shattuck Street, Lawrence, MA 01843. 3 To whom correspondence should be addressed 18 FERMENTATION OF POULTRY WASTE with 10-20% fermentable combined carbohy- OF PROBLEM DESCRIPTION drates produced an acidic silage. Broiler processing plants produce large In our previous studies on direct acidifica- quantities of offal, feathers, blood, and dis- tion of poultry offal and carcasses , putre- solved air flotation (DAF) sludge. Most offal faction was prevented when silage pH was is shipped to rendering plants for processing maintained below 4.5 and volatile nitrogen into animal feed supplements. However, rapid (NH3-N) content was less than 0.3%. The putrefaction of offal requires immediate ren- present study sought to evaluate lactic acid dering of fresh offalto prevent odor problems. fermentation using inexpensive carbohydrate- The hauling fee per ton of offal increases when rich industrial by-products as fermentation less-than-truckload quantities of offal are substrates and to establish a technically and transported. The utilization of offal becomes economically feasible lactic fermentation pro- more difficult when high summer tempera- cess that would stabilize poultry offal, blood, tures accelerate offal deterioration, which re- DAF sludge, and poultry carcasses. Specific sults in a poorer quality of poultry meal. objectiveswere: 1) to determine industrial car- Holding offal on weekends is most troul?!e- bohydrate by-product fermentability and the some to manage since a typical rendering plant minimum levels required to stabilize poultry stops operations on weekends to maintain carcass and offal silage, 2) to evaluate the plant equipment. Thus, developing a techni- effect of temperature on fermentation, 3) to cally feasible and economical method to stabi- test the feasibility of fermenting various poul- lize poultry offal would benefit both poultry try processing by-products and waste (offal, processing and rendering plants. blood-offal mixture, and DAF sludge-offal The disposal of poultry carcasses also mixtures) and poultry production wastes presents significant environmental, biological, (broiler carcasses, dead male chicks, and and financial problems for the poultry indus- hatchery waste), 4) to determine whether sup- try. Currently, carcasses are disposed of by plementation with a commercial silage culture burial, incineration, rendering, composting, or was necessary, and 5 ) to demonstrate the eco- landfilling [1,2]. Each of these processes, how- nomic feasibility of the optimal fermentation ever, has its unique flaws. Burial of dead birds process. in a pit can lead to ground water contamina- tion. Incineration is expensive and can poten- MATERIALSMETHODS AND tially pollute the air. Rendering dead birds into by-product meal is constrained by transporta- CARBOHYDRATE SOURCES A N D tion cost and restrictions on the movement o f SILAGE CULTURE diseased birds from one location (e.g., a Industrial carbohydrate-rich by-products county) to another [l]. Landfilling is subject to tested for fermentability were liquid molasses, land availability and limitations on diseased dry molasses, corn meal, non-delactosed dry carcass movement. wheys, and brewer’s solubles. Cane sugar was Lactic acid fermentation offers potential used as a carbohydrate control since it was a hope for economically disposing of dead birds good fermentation substrate . A commer- without contaminating the environment and cial microbial silage culture used in this study may also provide an income from the recovery contained Lactobacillus plantarum, Lactoba- of nutrients since the fermented product (si- cillus acidophiliis, Streptococcus faecium, lage) is suitable for rendering [l]. In fact, fer- Bacillus subtilk, and Aspergillus otyzae . mentation of dead birds, poultry offal, and edible food wastes with lactic acid bacteria is FERMENTATIONPROCESS very effective in inactivating pathogenic vi- Laboratoty Experiments: Dead broilers ruses and bacteria [3,4, 51. The ensiled prod- (dead-on-arrival birds), offal, and DAF sludge ucts from poultry viscera [ 6 ] ,poultry offal , were obtained from a local broiler processing swine slaughter-house offal ,and waste fish plant. Dead male chicks and hatchery waste (9,101have been demonstrated to be useful for came from a local commercial hatchery farm. incorporation into swine and poultry diets. Broiler carcasses (axe-chopped before grind- More recently, Murphy and Silbert [ l l ] re- ing), offal, chicks, and hatchery waste consist- ported that fermentation of broiler carcasses ing of egg shells, non-fertile eggs, dead embryos, and deadkull chicks were separately Research Report CAI et al. 19 ground using an Enterprise meat grinder with sive of the added water. The mixture was trans- a 12 mm sizing dice. The ground poultry waste ferred by an auger to a truck tank, held and was then mixed with a carbohydrate and incu- accumulated each day. When the tank was full, bated in a partially sealed plastic container at the silage was shipped to a plant in north Geor- a specified temperature. Samples taken at gia for rendering, where samples were taken various times during fermentation revealed for quality analysis. pH measurement and ammonia nitrogen analysis. DATA RECORDING AND ANALYSIS Silage culture inoculum (by weight of 0%, Ammonia nitrogen (volatile nitrogen) in 0.01% dry powder, or 2% activated liquid samples was analyzed according to Section culture) was added to carbohydrate-supple- 417D of APHA Standard Methods . mented ground poultry waste in a 2.3 liter Acidity (pH) wasmeasured with a CorningpH (0.5 gal) plastic container containing 1.5 kg of meter equipped with a flat surface combina- the final mixture. The activated liquid culture tion probe electrode. Statistical methods of was prepared by inoculating 0.3% dry silage regression, general linear model, paired t test, culture into 5% whey product solution in and Duncan's multiple comparison proce- water. This mixture was incubated at 37°C for dures [ 171 analyzed the experimental data. six to nine hr until lactic acid bacteria reached Significance was defined as probability of 0.05 108-109 CFU/ml. To ensure adequate mixing or less. All treatments and samples were run and to raise the final moisture of silage to in duplicate, unless otherwise specified. 60-70% for lactic acid bacterial fermentation [l, 151, carbohydrate materials were diluted RESULTS DISCUSSION AND before use with reagent-grade ( m e I) water  in the following ratios (w/w): dry SUBSTRATE FERMENTABILITY AND mo1asses:water = 1:2; corn meakwater = 1:2; CONCENTRATION dried whey:water = 1:2; cane sugar:water = Poultry carcasses and offal are deficient in 1:2; liquid mo1asses:water = 1:l; brewer's carbohydrates necessary to support the solub1es:water = 1:0-0.5. After mixing with growth of lactic acid bacteria. Therefore, inex- the carbohydrate and silage culture, the pensive carbohydrate supplements were ground carcass or offal was incubated at 21", tested to evaluate pH reduction as a measure 30", or 37°C for up to twenty-eight days, unless of fermentability at 37°C with the addition of otherwise specified. 2% activated liquid silage culture. All pH Field Experiments: Poultry processing values of carbohydrates (except corn meal) offal was obtained from a rendering plant in decreased from about 6.0 to 14.2 during the north Georgia. The offal was ground and first two days of fermentation (Figure 1). mixed with 6% whey product or 15% brewer's Carcasses treated with cane sugar (100% solubles, and with or without 0.01% dry silage sucrose), dry wheys (83% lactose for whey culture. The final mixture (about 40 kg) in a product and 72% lactose for sweet dry whey), 57 liter (15 gal) covered plastic container was liquid molasses (50% invert sugar), and dry manually homogenized with a metal potato molasses (38% invert sugar) had significantly masher and stored at ambient temperatures greater pH reductions (P c .05). This finding for twenty-two days. Ammonia nitrogen and indicates that sucrose, lactose, glucose, and pH were monitored during fermentation. fructose were more fermentable by indigenous Fermentation of poultry carcasses in field microflora and the silage culture than the trials was carried out on a poultry farm in north starch in corn meal. The addition of 6% liquid Georgia. Dead layer carcasses were received molasses (LM), 10% dry molasses (DM), 10% from the farm and ground with a 20" G.P.R. or 15% corn meal (CM), or 10% brewer's poultry grinder (Animal Health Sales, Inc., solubles (BS) did not produce adequate acids Selbyville, DE). About 1.5 kg of a 34% whey to stabilize the carcasses for eight days. Car- solution in water inoculated with 0.057% dry casses treated with corn meal yielded pH pat- silage culture was added to every five birds terns different from those with other (about 8 kg) during grinding. Therefore, the substrates during fermentation (Figure 1) ground mixture contained approximately 6% because the starch in corn meal was not dry whey and 0.01% dry silage culture exclu- directly fermentable. It had to be broken down by the silage culture, particularly Aspergillus JAPR 20 FERMENTATION O F POULTRY WASTE I n I n 10% es I n 15% es 4- -* 20% BS 3 Days Days FIGURE 1. Effectsof supplemental carbohydrate type and concentration on the p H of broiler carcasses during fermentationat 37°C: LM = liquid molasses, DM =dry molasses, CM = corn meal, WP = whey product, DW = dry sweet whey, CS= cane sugar, and BS= brewer's solubles. oyzae and Bacillus subtilis, before sufficient of tested substrate concentration (R2 > 0.91, acids could be produced. As a result, pH in- P < .OOl) for each of the carbohydrate supple- creased after the depletion of available sugars ments. A projected minimum of 6% CS, 8% and decreased again after the starch began to WP, 12% LM, 13% DM, 15% BS, or 24% CM break down. Carcasses fermented with 15% should have produced a pH of 4.2 and 4.4 or corn meal had approximately the same pH as less in carcasses ensiled for two and eight days, with 20% corn meal on day 8, but the former respectively. The minimum fermentable car- became putrid on day 6, having high pH and bohydrate levels required to produce end- NH3-N concentrations (Figures 1and 2). The point pH (14.2) are close to those reported pH (54.2) of carcasses fermented with 2 10% previously , but lower than those reported LM, 215% DM, 215% BS, 26% WP, 510% by Murphy and Silbert [ll].The discrepancy dry sweet whey (DW), or 2 6 % CS was signif- may be attributed to the different ground car- icantly lower than the pH of other silage dur- cass sizes. The larger the ground tissue size, ing storage for eight days (Figure 1). the more acid is nccded to penetrate it; there- Regression analysis showed that the pH was fore, more fermentable carbohydrate is re- highly correlated linearly with the square root quired as supplement. Research Report CAI etal. 21 contained 0.32% 2 0.11% NH3-N (Table 1). These findings were similar to those of the laboratory silage produced from one-day-old carcasses fermented with 6% whey product for eight days (Table 2). FERMENTATION TEMPERATURE Temperature is an important factor influ- encing fermentation. Carcasses and offal fer- I LM DY CY WP DW CS mented at 30°C and 37°C yielded acidic silage in the presence of sufficient carbohydrate Ca rbohyd rats Source (Figure 3). No differences (P > .60) in pH re- FIGURE 2. Ammonia nitrogen in broiler carcasses duction occurred between 30°C and 37°C. A fermented for eight days at 37°C with liquid considerably higher pH of poultry offal at 21°C molasses (LM), dry molasses (DM), corn meal (CM), whey product (WP), dry sweet whey (DW), or cane than 30°C and 37°C was observed when the sugar (CS). offal was fermented for eight days with 6% WP, 10% WP, 10% LM, or 15% BS because of slow Ammonia is an index of lactic acid fer- mentation because high values indicate high protein degradation. A successful lactic acid fermentation would result in low pH and low ammonia content. At least 10% LM, 13%DM, MONTH BATCH# pH NH3-N(%) 20% CM, 6% W, DW, or 6% CS was 8% July 1 4.9 0.21 needed in the carcasses to achieve an NH3-N 2 5.4 0.48 August content of less than 0.3% (Figure 2). Ammo- nia nitrogen increased with pH and they were September 3 4.8 0.36 positively correlated linearly (R = 0.91, October 4 4.9 0.26 P < .Ol). Thus, pH to agreat extent can be used November 5 4.6 0.28 to evaluate silage quality and stability. Mean 2 Standard 4.920.3 0.3220.11 Field studies on the fermentation of Deviation ground offal from three broiler processing plants at ambient temperatures of 6°C to 22°C showed that the addition of 6% whey product TABLE 2. p H of one-day-oldcarcassesfermentedfor and 0.01% silage culture stabilized the offal for eiaht d a w with carbohvdrate sumlement twenty-two days with an endpoint pH of 4.81 2 0.05 and an endpoint NH3-N concentration of 0.19% 2 0.01%. No statistically significant differences in pH and NH3-N content oc- curred among the offal from the different 670 WP plants during fermentation for twenty-two 4.73a 0.40a days. Ammonia nitrogen concentration in 4.69a 0.3Sa offal was not significantly different before and 10% LM 37 4.79a - after fermentation. The ground offal control 30 4.61a - (untreated offal) in this study putrefied during storage and had an NH3-N content of 0.7% at 21 4.61a - eight days. These results indicate that fermen- 15% BS 37 4.21b 0.33a tation at low temperatures inhibited ammonia 30 4.2.1b 0.32a production. 21 4.5? 0.30a Fermentation of poultry carcasses at am- bient temperatures on a 650,000 layer farm in north Georgia has been in operation since June of 1991. Carcasses fermented for five months from July to November showed that the carcass silage had a pH of 4.9 2 0.3 and JAPR 22 FERMENTATION OF POULTRY WASTE bation and the high buffering capacity of egg yolk and egg shell (calcium) accounted for the unsuccessful fermentation of this waste. Thus, proper fermentation of poultry waste requires the material to be fresh and have a low buffer- ing capacity. Studies of broiler carcass fresh- ness also revealed that it was more difficult to stabilize one-day-old carcasses than fresh car- casses. A substrate concentration of 10% liq- - uid molasses or 6% whey product added to 37 30 21 37 30 21 37 30 21 37 30 21 37 30 21 one-day-old carcasses might not produce suf- ficient acids to stabilize the carcasses for more than eight days, as the carcass pH was unstable and increased to 4.8 during storage for eight I days (Table 2). Therefore, old carcasses may a 5 need a higher concentration of fermentable carbohydrate to have a satisfactory lactic acid 4 fermentation for preservation. Spoiled poultry materials, however, cannot be stabilized by 3 fermentation. 37 3 o z i 373021 ~ 7 ~ 0 2 1 3021 37 3730 Offal silage had a higher acidity than car- cass (broiler or chick) silage (Figure 4A). A T e m p e r a t u r e (OC) similar phenomenon was observed (Figure 3) FIGURE 3. Effect of temperature on pH of broiler based on the same substrate treatment offal (A) and carcasses (8)fermented for eight days (e.g., 6% WP and 10% LM), since offal with whey product (WP), liquid molasses (LM), or brewer's solubles (BS). (viscera, heads, and feet) contains more car- fermentation at the lower temperature (Figure 3A). The opposite occurred when the "'A A I4akh.r). W a s h substrate concentration was low ( i e . ,6% LM), A Doad Yale Chicks presumably because the depletion of ferment- 5.0 0 BmilwOffal able carbohydrate stopped the production of - -L n acid at the higher temperatures (Figure 3A). Similar results appeared in fermented car- casses with 10% BS and 15% BS (Figure 3B). 4.0 A fermentation temperature of 21°C pro- duced a lower pH with 10% BS, but yielded a 3.5 ' 0 2 4 6 8 I IO higher pH with 15% BS than at 30°C and 37°C at eight days. Thus, an interaction between substrate concentration and temperature occurred. Whenever there was adequate car- bohydrate available for fermentation of poul- I P try offal and carcasses, a higher pH would be observed at 21°C than at 30°C or 37°C. POULTRY PROCESSING AND PRODUC- TION WASTE 0 2 4 6 8 IO 12 14 16 Fermented broiler offal, carcasses, and male chicks had a pH of 4.3 or less when stored Days of F e r m e n t a t i o n for eight days at 37°C (Figure 4A). However, FIGURE 4. pH of poultry waste materialsfermented the pH of fermented hatchery waste was sig- at 37%: (A) with 15% brewer's solubles; (8)mixtures of DAF sludge, brewer's soluble, and offal; nificantly (P c .OS) higher, resulting in putre- 10SLGIOBS80FL = 10% OAF sludge, 10% brewer's faction of the material after four days. The solubles, and 80% offal; 15BS85FL = 15% brewer's poor quality of the raw material before incu- solubles and 85% offal; etc. (wet weight basis). Research Report CAI et al. 23 bohydrate than the whole carcass on a weight of fermentation probably stemmed from mold basis. Thus, carcasses should require more growth resulting from repeated opening of the supplemental carbohydrate than offal for suc- container for pH measurements.These results cessful comparable fermentation. indicate that the level of indigenous lactic acid DAF sludge added to offal did not have a bacteria in poultry offal and carcasses was significant effect on pH at sludge concentra- adequate to ferment carbohydrates, also lead- tions of O%, 10% and 20% when fermented for ing to the rapid production of acid to prevent fourteen days (Figure 4B). The difference in putrefaction. A field study of the fermentation sludge-offal pH resulted from the influence of of broiler processing offal for eight days at brewer's solubles (BS) concentration rather ambient temperatures of k16"C at the render- than from the effect of sludge concentration. ing plant also showed no significant differ- Offal or sludge-offal ensiled with 15% BS had ences in acidity and ammonia content between a more stable pH than that with 10% BS. All offal silages with and without silage culture 15% BS-based offal and sludge-offal mixtures inoculation. Both offal silages had a pH of 5.0 had a pH close to 4.0 after storage from one to and NH3-N concentrations of 0.30%-0.34%. fourteen days (Figure 4B). We can conclude that adequate lactic acid bacteria are naturally present in poultry offal SUPPLEMENTAL SILAGE CULTURE and carcasses and that supplementation of Fermentation with a commercial silage commercial lactic acid bacteria is unnecessary culture inoculum (2% liquid culture or 0.01% for effective fermentation of these materials. dry powder) was not significantly different from that without inoculation (Figure 5). Some ECONOMIC FEASIBILITY differences in pH observed at the later stage Fermentationwith 15% brewer's solubles (BS, which contained 50-52% solids) was the 6.0 I 1 most inexpensive of the effective carbohydrate sources and concentrations tested (Table 3). The cost of this substrate was $8.3/1,000 kg silage (based on 1992 cost estimate). In addi- tion, fermentation of broiler offal, fresh car- casses, and one-day-old carcasses confirmed that 15% BS silage produced lower pH than the 6% or 10% liquid 3.5 L A molasseswhey product (WP)2). Although the (LM) silage (Table 6.0 I i cost of 10% LM was approximately the same 5.5t Offa' as for 15% BS (Table 3), offal and carcasses ensiled with the latter were more stable during storage for twenty-eight days. The endpoint pH of 15% BS based silage was 4.3, whereas the pH of 10% LM silage was 5.2. Moreover, the addition of 15% BS to ground broiler car- 3.5 I . 1 , . casses, offal, or DAF sludge-offal mixture I---------- (1:3.3 by wet weight) stabilized silage pH ( ~ 4 . 5 for sixty days. ) A typical poultry farm with 650,000 birds spends thousands of dollars annually on trans- portation costs and fees for landfilling dead birds. When lactic acid fermentation stabilizes the carcasses, the annual cost including over- head and materials will cost approximately $4,400 for fermentation with 6% whey product Days of Fermentation or $3,090 for fermentation with 15% brewer's FIGURE 5. Effect of silage culture supplementon the solubles (Table 4). If the fermented carcasses p H of broiler carcasses, offal, and DAF sludge-offal are saleable, the farm can realize a financial mixture (1:3.3 by wet weight) fermented with 15% brewer's solubles at 30°C. return on the fermentation investment, be- JAPR 24 FERMENTATION OF POULTRY WASTE TABLE 3. Cost estimates of carbohydrate supplements Based on sale in bu Whey product Brewers solubles Grinder, auger $1750/yr $175O/yr Facilities, supplies $ 400& $400/yr Whey product (6%) $2250/yr - Brewers solubles (15%) - $ 94Otvr Annual cost y w0r 0/ I $309O/yr Carcass silage sales ($0.02/lb) S5600/yr $5rn/yr Possible net return I $1200/vr SZlO/vr cause renderers may pay $0.02-0.03/lb [l]. dollars/provide economicbenefit for the poul- Therefore, unlike other disposal methods, fer- try farm but also reduce environmental con- mentation of carcasses could not only save tamination significantly. CONCLUSIONS AND APPLICATIONS 1. Effective stabilization of chicken processing offal, blood-offal and DAF sludge-offal mix- tures, and chicken carcasses can be achieved by lactic acid fermentation supplementedwith cane sugar, dried whey, molasses, and brewer’s solubles. The minimum concentration of substrate used to stabilize chicken offal or carcasses for eight days was 6% for cane sugar, 6% for dried whey, 10% for liquid molasses, and 15% for brewer’s solubles. Higher levels may be needed for longer stabilization of coarsely-ground older carcasses or offal. 2. Corn meal was a poor fermentation substrate. Carcasses ensiled with 10-15% corn meal putrefied after storage for four to six days at 37°C. Research Report CAI et al. 25 3. Fermentation of offal and carcasses was slower at 21°C than at 30°C and 37°C. Adding adequate fermentable carbohydrate produced a more stable silage at 30-37°C. 4. Stabilization of poultry carcasses required more supplemental carbohydrate than stabili- zation of poultry offal. 5. Indigenous lactic acid bacteria in chicken offal and carcasses fermented carbohydrates equally well with or without the supplementation of a commercial microbial silage culture. Thus, the addition of silage culture can be eliminated to reduce the cost of fermentation of these poultry wastes. 6. The addition of 15% brewer’s solubles to ground chicken offal, DAF sludge-offal mixtures, and chicken carcasses produced stable, acidic silage (pH < 4.5) for sixty days. This process seems to be the most economical and technically sound stabilization method to use on a large scale to preserve these materials for subsequent nutrient recovery. 7. Carcass silage production on a poultry farm proved that lactic acid fermentation to stabilize carcasses was technically and economically feasible if a renderer could provide a truck tank. Lower fermentation cost and higher silage quality would be expected if 15% brewer’s solubles was used as the supplement on the farm. Fermentation of carcasses may provide additional income for farms since the product was suitable for rendering. Furthermore, ensiled carcasses were reused and would not contaminate the environment like other carcass disposal methods. REFERENCES AND NOTES 1.Dobbins, C.N., J.r., 1990. Dead birddisposal through 10. Tibbells, C.W., R.W. Seerley, H.C. McCampbell, the use of Iactobaclllus fermentation (ensilage). Pre- and S .Vezey, 1981. An evaluation of an ensiled waste A sented at the Southeastern Poultry and Egg h o c . Conf., fish product in swine diets. J. Animal Sci. 52:93-100. Atlanta, GA. 11.Murphy, D.W. and S.A. Silbert, 1992. Presewation 2. Murphy, D.W. andT.S. Handwerker, 1988. Prelim- of and nutrient recovery from poultry carcasses subject to inary investigations of composting as a method of dead lactic acid bacteria fermentation. J. Appl. Poultry Res. bird disposal. Pages 65-72 in: Proc. 1st National Poultry 156-74. Waste Management Symp., Ohio State Univ., Columbus, OH. 12. Cai, T., 1993. Stabilization of Poultry Processing Wastes and Poultry Carcasses through Direct Chemical 3. Dobbins, C.N., Jr., 1988.m fermen ta- Acidification and Lactic Acid Fermentation. Doctoral tion: A method of disposal/utilization of carcasses con- Dissertation, University of Georgia, Athens, GA. taminated by pathogenic organisms or toxic chemicals. Pages 76-80 in: Proc. 1st National Poultry Waste Manage- 13. McCullough, M E , 1978. Silage: Some general ment Symp., Ohio State Univ., Columbus, OH. considerations. Pages 3-25 in: Fermentation of Silage: A Review. M.E. McCullough, ed. NFIA, West Des Moines, 4. Pancorbo, O.C., W.C. Merka, S.M. Russell, D.L IA. Fletcher, and R.W. Baslien, 1990. Destruction of bacte- rial pathogens and indicators in broiler processing waste 14. APHA, 1985. Standard Methods for the Ekamina- (offal) during lactic acid fermentation. Pa es 104-112 in: tion of Water and Wastewater. 16th ed. American Public Food Ind. Environ. Conf., Georgia Tech kesearch Insti- Health Assoc., Washington, DC. tute, Atlanta, GA. 15. SAS Instilute, 1988. SASiSTAT User’s Guide: 5. Sholls, EB. Jr., R . E Wooley, and J.A. Dickens, Release 6.03 Edition. SAS Institute Inc., Cary, NC. 1984. Anti-microbiceffects of - fermentation on edible waste material contaminated with infected car- ACKNOWLEDGEMENTS casses. Am. J. Vet. Res. 452467-2470. Financial sup ort for this study by Georgia Proteins, 6. Tlbbells, C.W. and RW. Seerley,. 1988. Poultry Inc., Cummin &A (Grant No. 25-21-RC294-113to the viscera ensiledwith . for owing University of h , , a Research Foundation) is gratefully and finishing s w i n e f 8 8 S 9 1 3 . acknowledged. 7. Tibbells, G.W., R.W. Seerley, a n d H.C. Liquid molasses (Blackstrap), dry molasses (Sweetlix McCampbell, 1987.Poultry offal ensiled with Lactobaril- 3 ) non-delactosed dry wheys (Whey Product and Sweet 8, lusi.ld@h for growing and finishing swine diets. J. ’ Dry Whey), and brewer’s solubles (Brewex) were ob- Animal Sci. 64:182-190. tained from Savannah Food and Industries (Savannah, GA), PM ag Product (San Francisco, CA), Land O’Lakes 8. Szakacs, C., J. Cyory, and L Slankovin, 1985. (Minnea olis, MN), and Anheuser-Busch (Williams- Presexvation of autoclaved slaujhter-house by-product. burg, VA?, respectively. Pages 1 6 2 1 in: Agric. Waste tilization and Manage- ment, Proc. 5th International S p p . on Agric. Wastes, The microbial silage culture used (SII-All in freeze- American Society of Agric. Engineers, St. Joseph, MI. dried powder form) was provided by Alltech, Inc., Nicholasville, KY. 9. Hassan, T.E. and J.L. Heath, 1986. Biological fer- mentation of fish waste for potential use in animal and poultry feeds. Agric. Wastes. 191-15.
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