Microbiological and Color Aspects of Cooked Sausages Made from a Standardized Porcine Blood Cell Concentrate
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1181 Journal of Food Protection, Vol. 70, No. 5, 2007, Pages 1181–1186 Copyright ᮊ, International Association for Food Protection Microbiological and Color Aspects of Cooked Sausages Made from a Standardized Porcine Blood Cell Concentrate BERNHARD NOWAK,* ADOLF HEISE,† NIKOLAI TARNOWSKI, AND THEDA VON MUEFFLING Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany MS 06-371: Received 10 July 2006/Accepted 12 November 2006 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/70/5/1181/1681357/0362-028x-70_5_1181.pdf by guest on 27 September 2021 ABSTRACT The objective of this study was to determine the potential for blood cell concentrates (BCCs) from pigs as an ingredient in food. Sausages were made for this study according to a basic recipe for a type of blood sausage that is common in Germany. First, sausages were produced with rind and kettle broth only, and different amounts (2.5 to 31%) of standardized blood cell concentrate (s-BCC) were added (15% table salt [NaCl] and 25% protein content). Then, sausages were made with whole blood and compared with s-BCC sausages; both the BCC and blood had been pretreated either with NaCl or curing salt (nitrite). The impact of BCC and blood on the color (La*b*) of these rind sausages was determined. Finally, blood sausages were made with 12% s-BCC and either natural spices or spice extracts. These sausages were investigated microbiologically and compared to customary commercial blood sausage products (with whole blood) in terms of aerobic plate count (APC), Enterobacteriaceae, sulfite-reducing anaerobic bacteria, coagulase-positive staphylococci, and spore-forming bacilli. The de- sired color parameters (L, 34.5; a*, 17.8; and b*, 10.6) were obtained with the addition of about 12% s-BCC. Curing the blood or BCC beforehand had no significant (P Ͼ 0.05) influence on the color. The microbial counts of both the blood (APC, 4.4 log CFU/g) and the natural spices (APC, 6.6 log CFU/g) were relatively high. The spices were responsible for the relatively high microbial counts in the sausages, particularly the bacilli (6.4 log CFU/g). However, these counts were comparable to those found in commercial blood sausages. The bacteria introduced into the sausage by the blood had no significant impact on the bacterial counts of the end product. The bacterial loads of the sausages produced with 12% s-BCC and spice extracts were significantly lower (APC and bacilli, 2.0 log CFU/g) than those of the other blood sausages (APC, ϳ4.4 log CFU/g; bacilli, 3.2 to 4.0 log CFU/g). Only a small fraction of the blood collected in slaugh- sausage are a low level of microorganisms and the color of terhouses is used for human consumption (3, 15). In fact, the product (1, 2, 15). The typical color is the result of the red blood cell concentrate (BCC) is even banned from the oxygenation (23) and oxidation of the heme group (specif- food chain in some countries (e.g., Germany). However, ically of the iron ion, Fe2ϩ to Fe3ϩ) (9), which are intro- this BCC has a high nutritive value and a microbiological duced into the sausage with the blood cells. Color is also status comparable to that of whole blood (16). Blood spoils affected by processing temperature (22); by the presence quickly and is subject to great variation in its initial micro- and amount of nitrite used as a curing salt (nitroso hemo- biological contamination (16, 17). To maintain the quality globin); and by the pH (2, 23). The addition of salt alone of blood or its cell concentrate until use, these substances is said to lead to brown-black (24) or grayish red (10) col- Њ must be stored at 3 C or should be preserved, such as by ors, but Stiebing (23) described only slight variations in red the addition of 15% table salt (NaCl) to the BCC (16). colors in nitrite-free and cured blood sausages. One of the oldest known sausage types is the black The aim of the present investigation was to show the pudding produced from the collected blood of slaughtered potential for the use of BCCs in food products. Rind sau- animals (12, 23). Because of their high water activity sages were manufactured without and with various amounts (ϳ0.96 to 0.99) and pH values (6.2 to 7.3) in blood sau- of BCCs to determine the influence of BCCs on microbi- sages or blood pancakes (13, 20, 21, 25), these products ological status and color. Moreover, blood sausages were spoil rapidly. The microbiological quality of the product is produced with different amounts of standardized BCC (s- significantly affected by the initial bacterial load in the blood and in the spices and other ingredients (meat, fat, and BCC, 25% protein content and 15% NaCl) and with either rind) used (5, 25). Another crucial factor is good manufac- natural spices or spice extracts for a comparison (6) of their turing practice (6). Among the typical bacteria found in microbiological and sensory qualities with the rind sausag- blood sausages are bacilli, clostridia, Enterobacteriaceae, es and commercial blood sausage. and micrococci/staphylococci (5, 13, 19, 20). MATERIALS AND METHODS The two most important quality parameters of blood BCC collection and preparation. Porcine BCC was col- * Author for correspondence. Tel: ϩ49-511-856-7319, Fax: ϩ49-511-856- lected at a commercial slaughterhouse. The blood was collected 827319; E-mail: [email protected]. from pigs in a sticking carousel (RotaStick, Anitec, Malmø, Swe- † This article is dedicated to Adolf Heise, who died in June 2006. den) with hollow knives. Citrate (0.3 to 0.4% [wt/vol]; trisodium 1182 NOWAK ET AL. J. Food Prot., Vol. 70, No. 5 TABLE 1. Experimental design of the study and composition of the sausage variations produced R1–R6: rind sausages S1, S2: blood sausages Part 1A Part 1B Part 2 R1 R2 R3 R4 R5 R6 S1 S2 Rind sausage ingredients (% in final rind mass) Cooked rinds 47 47 47 47 47 47 47 47 Kettle broth 53 50.6, 46, 41, 36.5, 32, 27, 22 43, 38 43, 38 23, 8 23, 8 41 41 BCC pretreated with: 15% NaCl — 2.4, 7, 12, 16.5, 21, 26, 31 10, 15 — — — 12 12 15% curing salt — 10, 15 — — Downloaded from http://meridian.allenpress.com/jfp/article-pdf/70/5/1181/1681357/0362-028x-70_5_1181.pdf by guest on 27 September 2021 Whole blood pretreated with: 1% NaCl — — 30, 45 — 1% curing salt — — — 30, 45 Total (%) 100 100 100 100 100 100 100 100 Blood sausage ingredients (% in final sausage) Rind mass 44 44 Meat and fat 55 55 Natural spices 1— Spice extract —1 citrate and sodium chloride, 7:3; Fibrisol, Fibrisol Service, Vi- bath for between 75 and 90 min and then cut into 1-cm cubes. ernheim, Germany) was added to the blood as an anticoagulant. Back fat was cut into 0.5-cm pieces. The cut meat and back fat The blood flowed through cooled tubes toward a separator (Hank- were stored frozen in bags until use. kiija, Helsinki, Finland, modified by Anitec) with approximately Some of the blood sausages (S1; Table 1) were produced with 500 plates turning at 1,450 rpm, and the resulting plasma and a natural spice mixture (Hannoversche Gewu¨rzmu¨hle, Hannover, BCC were stored in separate tanks. Cooling to ϩ2ЊC was contin- Germany) containing pepper (4.0 g/kg of sausage), nutmeg (1.0 ued inside the tanks. The BCC was transferred to sterile 1-liter g), pimento (1.0 g), cloves (0.5 g), caraway (1.0 g), celeriac (1.0 glass bottles and put into a cooler equipped with chilling aggre- g), and marjoram (1.5 g). Other blood sausages (S2; Table 1) were gates. A thermometer was inserted into one bottle of each trans- made with a mixture of extracts of the same spices (Ru¨ther Gew- porter for temperature recording during transportation. Upon ar- u¨rze, Holzwickede, Germany). The spices in the extract mixture rival at the laboratory, a portion of the BCC was used immediately were used in the same quantities as the natural spices. for the determination of protein content (Kjeldahl method). The Cleaned porcine colons were used as casings (Hannoversche rest of the BCC was kept at Յ4ЊC until microbiological analysis Gewu¨rzmu¨hle). the following day. Depending on the results of the protein determination, the Sausage production. Table 1 gives an overview of all the BCC was standardized to (i) 25 g of raw protein per 100 g of s- sausage variations produced (R1 through R6; S1 and S2) in the BCC with sterile physiological sodium chloride (NaCl) solution sequence (parts 1A, 1B, and 2) and the amounts of the various and then to (ii) 15 g of NaCl per 100 g of s-BCC with crystalline ingredients. sodium chloride (Merck, Darmstadt, Germany). All components In the first part of the study, sausages were made from a were thoroughly mixed by homogenization in sterile bags in a mass of rind and kettle broth milled in a colloid mill and filled laboratory blender (Stomacher 400, Seward, London, UK). The s- in casings (R1). At the same time, rind sausages were manufac- BCC was kept at room temperature (21ЊC) for 6 days until further tured with the addition of s-BCC (R2). Recipes for rind mass processing. All samples collected were subjected to the same pro- sausages (R1 through R6) were calculated to yield a final weight cedure.