Maataloustieteellinen A ikakauskirja Vol. 62: 381—395, 1990 Storage properties and quality of meats deboned by different methods L. RIIHONEN, J. LAINE and T. KÄRKKÄINEN Finnish Meat Research Centre, Box 56, SF-13101 Hämeenlinna, Finland Abstract. The storage properties ofmechanically deboned beef and pork were studied at storage temperatures of +4°C for up to 6 days and at -24°C for up to 140 days. Two types of machines were used for the separation of the meat, a pressure-based Inject Star machine (6 test series) and a Poss prototype machine based on scraping (2 test series). The samples were recovered using a disinfected machine and were immediately packaged in cartons and peri- odically analysed for their chemical, microbiological and physical characteristics. The beef sam- ples maintained their overall qualitybetter than the pork samples both in cold and frozen stor- age. The differences (P<0.05) between the samples recovered using the two machine types were reflected in the contents of ash, calcium, phosphate, microbes and dry matter. Index words: mechanically deboned meat (MDM), quality of MDM, storage properties of MDM Introduction Mechanical deboning is more economical than hand boning because almost all of the meat can thus be recovered and used in meat products. The machines can handle either chopped bones or bones precleaned with a knife to varying stages. Mechanically deboned meat differs from other meats primarily in its content of sub- stances originating from bones and bone mar- row, e.g. calcium, phosphorus, fluorine and iron. According to most studies, these sub- stances are of benefit rather than a disadvan- tage to the meat industry (1, 2). Goldstrand (3) reported that the protein content of meat separated from the neck bones of a pig was 14.2—15.1%, the fat con- tent was 24.7—29.9% and the moisture 53.7— 60.3%. Meat mechanically separated from the bones of a low-fat bull contained a high con- tent of protein (16 —17%) and only little fat (9.9—24.4%) whereas meat separated from ham bones contained 10.0% protein, 42.3% fat and 44.6% moisture. These results are rather similar to those published by Field et al. (4) from which it can be calculated that the highest protein contents are in meat separated 381 JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND https://www.c-info.fi/en/info/?token=h-LyagUrGj6e9cEm.zwpozkDuhKm--Ms3iFVdcw.LMxg1grnGHRvQhN5stAyMq0_Lmij7CyHDzfARt8aZg1R4TV0Zno_9WyY10FTVj_-dZ89EEsqhbiXeAtZf-UG-qSJJgLtsS013Nb9f2YC4NQnz7upbk0B41o_b3rAr7YdctM9c__VNJ6w2G9bNw22Pmf-haPl7HmM6ICyMALz9T5pKKvwyJFsvl4PCSkTsmyYpn-0-aatRuSJfYnrVIb8 from the sow loin bones (14.01%), veal frame bones (17.57%), veal backbones (15.98%) and bull’s neck bones (17.18%). The highest fat contents were in meat separated from blade bones (42.37%) and thigh bones (41.89%). The mean calcium content of bones of vary- ing ages and derived from different animal species and anatomical sites is about 37% of the ash content of the bones (5). When the de- boning is based on scraping, calcium separa- tion from the bones is more efficient than that achieved using other machine types. Mechanically deboned meat contains small amounts of bone particles, the size and quan- tity of which depend on the machine used and the perforation size and the condition of its strainers (6). The bones of older animals con- tain more calcium and are therefore harder than the bones of younger animals (7, 8). According to Field (9) the bone content is 0.05—0.31% in meat deboned by hand from pork head and neck bones. The quality of meat can be estimated very well by its content of microbes. In practice the meat is unfit for human consumption if the number of bacteria is more than 1.0 x10s cfu/cm 2 on the surface, or 0.5—1.0 x10s cfu/g inside the meat. If the microbial count is I.oxl07cfu/g, the meat is of poor quality (10, 11). The pH value of meat has a great influence on microbial quality. If thepH of fresh meat is higher than 6.0, its storage properties de- teriorate; when the pH is 6.5, the meat is of questionable quality. Moreover, this pH cri- terion cannot be directly applied to mechani- cally deboned meat because of thebone mar- row released during separation, which may in- crease the pH up to 6.6. Thus, pH is not the only indication of microbiological deteriora- tion of mechanically deboned meat, even though high pH values improve the growing conditions of microbes (4). High pH also limits the shelf life of mechanically deboned meat, implying that it should be used or fro- zen as quickly as possible after deboning. The aim of this investigation was to evalu- ate factors, the quality, storage properties and usage restrictions of mechanically deboned meat. The amount of bone matter getting into meat in mechanical deboning was also ana- lysed. Process variables were; machine type, animal species, fat content of MDM, frozen storage period, packaging material. Materials and Methods Samples The origin of bone, sample coding and the temperature after mechanical separation are presented in Table 1. In the sample codes B stands for beef, I for Inject Star deboner and the first P stands for pork and the second P for Poss deboner. Thus samples 811, 812.. (mechanically deboned beef) and samples PI 1, P 12.. (mechanically deboned pork) were re- covered using the Inject Star machine and samples BP and PP using the Poss machine. The temperature of bones to be processed was + 6°C, the freezing temperature 40°C, utili- zationof freezing air 98000 mVh in 6900 m 3, and the temperature of frozen storage -24°C. The temperature of the meat was measured immediately after mechanical separation, which happened next morning after cutting except aged bones after 72 hours. Experimental Procedure and Equipment The investigation was carried out partly at the production plant Osuusterastamo Kar- Table 1. Materials used for mechanical deboning. Sam- ples B 1 (MDB) and PI (MDP) were recovered using the Inject Star machine and samples BP and PP using the Poss deboner. Meat temperatures were measured immedi- ately after the mechanical separation. Samples Origin of bones Temperature ofMDM(°C) 811 Beef, bones of bulls 10.2 812 Beef, backbones of bulls 10.3 813 Beef, bones of cows 13.0 BP Beef, bones of cows 17.0 Pll Pork, bones of pigs 10.3 PI2 Pork, bones of pigs 8.8 Pl 3 Pork, aged bones of pigs 9.7 PP Pork, bones of pigs 15.0 382 383 japortti in Mikkeli and partly in Hämeenlin- na at the Finnish Meat Research Centre. The machine mainly used in the tests was a pres- sure type Inject Star (P-60) machine (Holl- stein-Fuhrman, Vienna, Austria). The other machine was an auger-type Poss (PDX) ma- chine (Poss Limited, Hamilton, Canada) from the production plant of Lihapolar in Kuopio. Packaging and storage properties Immediately after the mechanical deboning, the test meats for freezing were packaged in 3 kg samples in high density polyethylene (HDPE)-coated cartons and frozen. Samples for +4°C storage tests were packaged in HOPE plastic bags. Storage properties were studied at + 4°C af- ter (0), 1, (2), 3, (5), 6 days and at -24°C af- ter 1, 63, 84, 112 and 140 days. Analytical methods Chemical analyses Moisture andfat. Moistureand fat were de- termined by the method of Nilsson and Ko- lar (12). Ash Ash contents were determined according to the Method K 27/1967 of the Finnish Meat Research Centre (13). The sample (10 g) was weighed into a porcelain crucible and dried at 135°C for one hour. The sample was ashed and weighed after cooling in a desiccator for 1/2 h. Calcium and bone particles To determine the amount of calcium, com- plexometric EDTA-titration was used (14). The size of thebone particles was determined by the KOH-method (15). A homogenized sample was dried and boiled in an alcoholic KOH solution and dried. The bone particle content was calculated from the dry weight. The average size of the bone particles was de- termined by microscopy. Phosphate Phosphate content was analysed as ammo- nium phosphomolybdate with a Technicon- Analyzer 11, technicon industrial method No 328-74A, 1975. Protein Protein contents were analysed according to the AOAC method (16). The amino acid analyses were carried out using theWaters as- sociates chromatography-systems according to Dong and Gant (17) and Hsu et al., (18) at the Food Research Laboratory of the Tech- nical Research Centre of Finland. Peroxide value and free fatty acids Peroxide oxygen content (milliequivalents of oxygen/kg) was determined iodometrical- ly by adding potassium iodide into an acidi- fied solution. The liberated free iodine was titrated with thiosulpahte. The percentage of free fatty acids (FFA-%) was obtained by titrating with alkali (Methods K 31/1.12.1967 and K 32/1.12.1967 of theFinnish Meat Re- search Centre which are modified by accord- ing to Wheeler 19). Thiobarbituric acid value (TBA value) The TBA value denotes mg of malonalde- hydes in 1000 g of fat (20). Connective tissue Connective tissue was estimated from the content of hydroxyproline, a characteristic component of collagen (21). The method is based on oxidization of hydroxyproline and subsequent hydrolysis to pyrrole with klor- amin, which results in the formation of red coloured dimethylaminobenzoaldehyde. The absorption was measured at 560 nm (22). pH value pH was determined with pH-meter WTW 521 (Wissenschaftliche-Technische Werkstat- ten, GMBH) with Ingold-electrode, 405-60-SS. Microbiological methods Aerobic plate count The total count of aerobic microorganisms was cultivated on Plate Count agar (Tryptone- glucose-yeast agar, Difco) at 30°C (72 h), according to the Method 86/1986 of the Nor- dic Committee on Food Analysis. Coliform bacteria For evaluation of coliform bacteria the Method 44/1975 of the Nordic Committee on Food Analysis was used (24). The coliforms were evaluated both at 37°C (24 h) and at 44°C (24 h) using VRB-agar (Difco). Faecal streptococci Faecal streptococci were determined by the Method 68/1978 of the Nordic Committee on Food Analysis using M-Enterococcus Agar (Difco) at 37°C (48 h). Lactic acid bacteria Lactic acid bacteria were quantified using the standard microbiological instructions, and were cultivated in Rogosa Agar (LBS-agar, BBL) at +37°C (72 h). Physical methods Colour The colour intensities of the samples were determined using a reflectometer (Diffusion Systems LTGD, (Hanwell, London, UK, model 43). Diffuse reflection by scattering, in contrast to regular reflection, allows penetra- tion of light into the material and the absorp- tion of this energy during the reflection process (23). The devicerecords the colour as a meter reading on a percent scale and was calibrated to a white 100% reading and a given grey 36% reading. Statistical analysis The results were analysed statistically using a Multiplan graph method and the Windows- Exel graph programme. Standard deviations were calculated for all the variables studied during storage. Two-tailed t-tests were used to evaluate differences between the samples. Analyses were carried out on three samples in duplicate. Results and Discussion Basic composition. In plotting the basic composition of the samples, the following parameters were analysed; fat, dry matter, protein, ash, calcium, phosphate, connective tissue protein, colour and pH. Fat content. The objective of this study was to obtain samples in which the fat contents varied as much as possible. In beef samples, sample 813 had the highest fat content, 29.8% and sample BP the lowest, 23.6% (P<0.005). In the pork samples, sample PP had the highest fat content, 20.7% and sample PII the lowest, 18.2% (P<0.05) of the values ana- lysed (Table 2.) The content of dry matter varied in accord- ance with the fat content, ranging between 35.4 and 44.4%. Protein content. In beef samples, sample BP had a slightly higher protein content than the other samples, especially compared with sample 811. In pork samples, no significant differences were found with the exeption of samples PI2 and PP (Table 2). The amino acids were determined and the essential ami- no acid (EAA) profile (lysine, methionine, cystine, threonine, isoleucine, leucine, valine, phenylalanine and tyrosine and also trypto- phane) of the samples was calculated accord- ing to the method of Hsu et al. (18). In this method, proteins are hydrolysed in 6N HCI solution and analysed using an amino acid analyser. The results are presented in Table 3. Sample PII had the highest analysed values of the following amino acids: phenylalanine, histidine, arginine and cystine. Field (24) also reported that because bone marrow, as well as blood, contains liberal amounts of ly- sine, leucine and histidine, these amino acids 384 Table 2. Composition of mechanically deboned meat. Sample Fat% Protein% Ash% Calcium% CT% MDB 811 26.2»" 13.85» 1.39" 0.29" 0.54" 1.49« 812 27.7» 14.45 1.30* 0.26* 0.53 e 1.68" 813 29.8 M 14.00 1.30f 0.27' 0.55' 1.45f BP 23.6 W 15.85' 2.94drf 0.86 d«' 1.16d'r 2.89dtf MDP Pll 18.2»» 15.40 1.13« o.lB* 0.47" 1.14' Pl 2 19.5 15.35" 1.20h 0.19" 0.46" 1.04d PI3 20.3» 15.75 1.09 1 0.12' 0.45 1 1.41' PP 20.7" 16.05» 3.14* 0.94» hi 1.26«h ' 1.91d" 811, 812 and 813 are MDB and Pll, Pl 2 and PI3 MDP from Inject Star deboner. BP and PP are MDB and MDP from Poss deboner. CT % is connective tissue. Mean values in the same column (in the groups of MDB and in the groups of MDP) bearing a common superscript are significantly different, ab P<0.05, dcf P<0.005 and *hi Pl.l mg/kg the sample is poor. On the other hand if perox- ide value <2 meqO/kg the sample is good and when FFA-% value < 1 the sample is good (31). Microbiological changes. According to Kärkkäinen (11) the surface and inside flora of meat kept in cold storage is composed mainly of gram-negative bacteria, belonging to the genera Pseudomonas, Alcaligenes, Achromobacter, Flavobacterium and Serratia and gram-positive Micrococcus. After slaugh- tering, depending on slaughter hygiene, the bacterial count on the surface of the carcass is 102—l04 cfu/cm2 . In the case of pork this bacterial flora consists mainly of bacteria be- longing to the genera Pseudomonas and Lac- tobacillus. Beefsamples. The quantity and accumula- tion of bacteria in samples 811 and 812 were similar during the whole follow-up of the keeping qualities in storage. Compared with the other samples, the amount of aerobic bac- teria in sample 813 increased considerably more quickly (Fig. 6). Sample BP, recovered in the Poss machine, had a lower initial microbial content than the samples recovered by Inject Star. The count of all groups of mi- crobes in sample BP showed the most obvious increase after two days. The lactobacillus count in sample BP was lower than in the other samples during the whole storage pe- riod, although the growth of the population was faster. The rapid growth of lactobacillus was also indicated by the reduction in pH. The count of thermotolerant coliformbac- teria of sample 811 remained lower than the corresponding microbial counts of the other samples throughout the storage period. Be- cause these coliform organisms have the Fig. 5. Free fatty acid values (FFAt'o) of mechanically deboned meat samples during storage at +4°C. Standard deviations were <0.07. 811, 812, 813 are mechanically deboned beef samples from the Inject Star deboner. BP is from the Poss deboner. PII, PI2, PI3 and PP are corresponding samples of mechanically deboned pork. 389 characteristics of faecal spoilage organisms, the original contamination of sample 811 was less than in the other samples. Taking into ac- count the keeping qualities of lipids and the microbiological keeping qualities, sample BH was the best, followed by samples BP, 812 and 813. Pork samples. The growth of the microbial genera analysed in samples PH and PI2 was very similar, apart from the count of lactic acid bacteria of sample PH, which remained almost constant throughout the storage pe- riod. The temperatures of the meats recovered from the Poss deboner were 13.0—15.0°C and from the Inject Star deboner 8.8—13.0°C. It seems apparent that because the meat was for such a short time at the recovering temper- ature (before deboning the temperature was between +4°C and +6°C, and immediately after deboning was reduced to +4°C or 40°C), this temperature should not have a significant effect on the quality of mechani- cally deboned meats. According to Newman (29) legislation usually specifies the tempera- ture below which the bones must be stored (usually -l- 7°C or less) and the maximum time of storage (3 —5 days, longer if stored below O°C) The keeping qualities of samples PI3 and PP were somewhat better than those of the other samples. Keeping qualities at —24°C. Keeping qualities in frozen storage were ob- served by analysing the samples after 1, 63, 84, 112 and 140 days of storage. Some sam- ples were also analysed after 28 days. pH -value. Beefsamples. Samples 811 and BP had almost the same initial pH values, af- ter which sample BP remained at a significant- ly higher level throughout the survey pro- gramme. Samples 812 and 813 were similar and had the lowest pH values at all the sam- plings. Fig. 6. Aerobic microbial counts of mechanically deboned meat samples during storage at +4°C. Standard devia- tions varied between 0.01 and 0.15. BI 1, 812, 813 are mechanically deboned beef samples from the Inject Star deboner. BP is from the Poss deboner. PI 1, PI2, PI3 and PP are corresponding samples of mechanically deboned pork. 390 Pork samples. The changes of the pH values in pork samples were very similar to those in beef samples. In comparing the changes from the initial pH value in the meat recovered by the two machine types, pH in meat recovered using the Poss machine increased considerably higher, and remained higher throughout the whole survey programme, whereas the pH values of samples PI2 and PI3 remained con- stant (Fig. 7). Colour. Beef and pork samples recovered using the Poss machine were lighter in colour than samples from the Inject Star. Otherwise, changes in all samples, except 813, showed a similar random variation during frozen stor- age. The colour of sample 813 remained al- most constant. Changes in lipid quality. Beefsamples. The peroxide value of sample 812 showed the greatest increase during the first 84 days, af- ter which it almost levelled with 811 (Fig. 8). The initial peroxide value of the BP sample was high, but it soon decreased and then re- mained below average. The quantities of free fatty acids showed rather similar changes in all the samples, as did many other parameters of these samples. Pork samples. All the pork samples be- haved in a similar way. Rancidity advanced faster and more vigorously than in the beef samples. On the basis of the TBA, peroxide and free fatty acid (FFA-%) values, sample PI2 (me- chanically deboned meat from bones of pigs recovered using the Inject Star deboner) was of inferior quality compared with the other samples. The sample recovered using the Poss machine scored between the samples recovered with the Inject Star. The free fatty acids of the beef samples re- mained almost constant. The peroxide and TBA values of the pork samples indicated that pork fat deteriorates considerably faster than beef fat. This was particularly evident from the analysis results of the samples after 63 days of frozen storage. As expected, the free fatty acid values ofpork samples were higher than those of beef, because pork fat contains more polysaturated fatty acids (Fig. 9). Microbial counts Beefsamples. Samples BP and 812 had the lowest aerobic plate count. The quantity of aerobic microbes in samples 811 and 813 re- mained almost constant throughout the period Fig. 7. The pH values of mechanically deboned pork samples during storage at 24°C. Standard deviations were <0.06. PI 1, PI2, Pl 3 are mechanically deboned pork samples from the Inject Star deboner, PP from the Poss deboner. 391 of frozen storage (Fig. 10). When studying coliform bacteria, sample BP was noted to have the lowest microbial counts during the survey. The coliform count of sample 813 increased clearly by the 63rd day, and then remained al- most constant. Sample BP had the lowest counts of faecal streptococci and lactic acid Fig. 8. Peroxide values (milliequivalents of oxygen/kg) of mechanically deboned meat samples during storage at 24°C. Standard deviations were <0.32. 811, 812, 813 are mechanically deboned beef samples from the Inject Star deboner. BP is from the Poss deboner. PII, PI2, PI3 and PP are corresponding samples of mechanically deboned pork. Fig. 9. Thiobarbituric acid values (TEA, mg/kg) of mechanically deboned meat samples during storage at 24°C. Standard deviations were <0.66. Bit, 812, 813 are mechanically deboned beef samples from the Inject Star deboner. BP is from the Poss deboner. PI 1, PI2, PI3 and PP are corresponding samples of mechanically deboned pork. 392 bacteria, and sample 812 the next lowest. The same applied to coliform bacteria, particularly in the case of coliform bacteria growing at + 44°C. Sample 81l had the third lowest of the above-mentioned bacterial counts. Pork samples. Sample PII had higher counts of aerobic and faecal bacteria than sample PI2. In other respects it was similar to the other samples. On the basis of the coli- form and faecal bacteria, sample PI2 had the Fig 10. Aerobic microbial counts, log(cfu/g), during storage at -24°C in A) mechanically deboned beef samples and B) mechanically deboned pork samples. Standard deviations varied between 0.05 and 0.51. 811, 812, 813 are mechanically deboned beef samples from the Inject Star deboner. BP is from the Poss deboner. PI I, PI2, PI3 and PP are corresponding samples of mechanically deboned pork. 393 best keeping qualities. Frozen storage had very little effect on the count of lactic acid bacteria. All the samples had similar counts. Conclusions Both in cold and frozen storage, the beef samples generally maintained their quality bet- ter than the pork samples. The differences be- tween the samples recovered using the pres- sure-based Inject Star deboner and the scrap- ing-based Poss-prototype deboner were clearly evident in the contents of ash, calcium and phosphate and dry matter. The microbial counts also differed. This investigation leads to the conclusion that, ifMDB and MDP must be kept in cold or frozen storage, MDP should be used after shorter storage periods than MDB probably after no more than about six weeks. Acknowledgements. We are grateful to Osuusteurasta- mo Karjaportti, Lihapolar Oyand Ulkomarkkinat Oy for financial support during this investigation. References 1 Kastner, C.L. and Kropf, D.H., 1986. Processed meat products and safety issues. Dairy and Food Sani- tation, 6: 186—193 2 von Winter, F.F., 1978. Gewinnung und Verar- beitungvon Separatorenfleisch. Die Fleischerei 29(7); 9—ll 3 Goldstrand, R.E., 1975. Mechanically deboned meat yields and product characteristics. Proc. 28th Recipro- cal Meat Conference, Chicago, 116 4 Field, R.A., Kruggel, W.G. and Riley, M.L., 1976. Characteristics of MDM hand separated meat and bone residue from bones destined for rendering. J. Anim. Sci. 43: 755—758 5 Field, R.A., Riley, M.L. and Corbridoe, M.H., 1974. Influence of yield on calsium content of mechan- ically deboned lamb and mutton. J. Food Sci. 39: 285—287 6 Field, R.A., Olson-Womack, S.L. and Kruggel, W.G., 1977. Characterization of bone particles from mechanically deboned meat. J. Food Sci. 42: 1406—1407 7 Grunden, L.P. and Mac Neil, J.H., 1973. Examina- tion of bone content in mechanically deboned poul- try meat by EDTA and atomic absorption spec- trophotometric methods. J. Food Sci. 38: 712 —715 8 Bijker, P.G.H., Gerats, G.E., Van Logtestijn, J.G., Koolmees, P.A. and Fransen, T., 1979. Methods to determine the bone content and size of the bone particles in mechanically deboned pork. Proc. 25th Eur. Meet. Meat Res. 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Bepaling van de harde- botresten grootte van de botdeeltjes in separatorvlees. Tijdschr. Diet geneeskd, 110: 969 970 16 Anonymous, 1975. Determination of protein content by the Makro Kjeldahl method. AOAC 1975 17 Dong, M.W. and Gant, J.R., 1985. Highspeed liq- uidchromatographic analysis of amino acids by post- column sodium hypochloride-o-phtalaldehyde reac- tion. J.Chromatocraphy 327: 17—25 18 Hsu, G.W., Sutton, M.0., Banjo, M.0., Satterlee, L.D. and Kendrick, J.G., 1978. The C-PER and T- PER asseys for protein quality,Food Technol. 32(12): 68—73 19 Wheeler, D.H., 1961. Öle und Fette. DGFC-IV6A, 7 20 Sedlacek, 8.A.J., 1958. Beurteilung der Walnuss- kerne durch objektiv Ranzigkeit- Methoden. z.L.U.F. 107: pp.28—32 21 Price, J.F. and Schweigert, 8.5., 1987. The Science of Meat and Meat Products. Westport, pp 81 —88 394 22 Weber, R., The determination of hydroxyproline and chloride in meat and meat products. Simultaneus oper- ation with nitrogen and phosphorus determinations. Nr 7 (1973) Technicon International Division SA, Geneve 23 Stark, E.W., 1986. Diffuse Reflection. Uses that af- fect our Lives, The Physics Teacher 3, 144—152 24 Field, R.A., 1975. Recovery of protein from bones by mechanical deboners. Proc. 21th Eur. Meet. Meat. Res. Work., Bern, pp. 100 —101 25 Field, R.A., 1976. Mechanically deboned red meat. Food Technol. 30(9); 38—48 26 Field, R.A. and Arasu, P., 1981. A simple method for estimating amount of red marrow present in mechanically deboned meat. J. Food Sci. 46: 1622—1623 27 Prost, E., 1984. Nutritive value of mechanically de- boned meat. Meat, Poultry and Game. Medycyna, Weterynaryjna; 40; pp.666—670; 0017 Ref; 28 Field, R.A., 1981. Current status of mechanically de- boned beef and pork. Proceedings of 34th Ann. Reciprocal Meat Conference, Pub. National Livestock and Meat Board. Chicago, 111 pp. 143—1463—146 29 Newman, P.8., 1980. The separation of meat from bone A review of the mechanics and problems. M. Sci.s: 171—200 30 Ockerman, H.W., Houben, J.H, and Krol, 8., 1985. Effect of Bone Source and Storage on the Role of Mechanically Deboned pork in Rancidity Development in a Cooked and Smoked Sausage. J.Food Sci. 50: 1551—1555 31 Pohja, M.S., 1987. Personal communication. Deb Ms received July 12 1990 SELOSTUS Eri menetelmillä luista erotetun lihan laatu ja varastointiolosuhteet L. Riihonen, J. Laine ja T. Kärkkäinen Lihateollisuuden tutkimuskeskus PL 56, SF-13101 Hämeenlinna, Suomi Työssä tutkittiin mekaanisesti naudan ja sian luista ero- tetun lihan varastointiolosuhteita + 4°C lämpötilassa aina kuuden vuorokauden ja 24°C lämpötilassa 140 vuoro- kauden säilytykseen asti. Tutkimuksessa olevat lihat ero- tettiin paineeseen perustuvalla Inject Star koneella (6koe- sarjaa) ja kaavintaan perustuvalla Poss koneella (2 koe- sarjaa). Näytteet kerättiin puhtaalta koneelta ja pakat- tiin välittömästi, analysointi suoritettiin tietyin väliajoin kemiallisfysikaalisesti ja mikrobiologisesti. Nautanäytteet säilyivät laadullisesti parempina kuin sikanäytteet niin kyl- mävarastoinnissa kuin pakkasvarastoinnissakin. Eri ko- neilta saaduilla näytteillä eroa (P<0.05) havaittiin tuh- ka, kalsium, fosfaatti, mikrobi ja kuiva-ainepitoisuuk- sissa. 395