Browsing by Subject "pakkaus"
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(University of HelsinkiHelsingin yliopistoHelsingfors universitet, 2003)Elintarvikkeiden pakkaaminen kertakäyttöpakkauksiin on aiheuttanut yhä laajamittaisemman ympäristöongelman. Perinteisesti pakkausjätteet ovat joutuneet kaatopaikoille tai jätteenpolttolaitoksille, mutta yhä etenevässä määrin elintarvikepakkauksia on pyritty keräämään hyötykäyttöön. Tässä kirjallisuuskatsauksessa olen tarkastellut eläinperäisten elintarvikepakkausten kierrätystä ja hyötykäyttöä. Olen tarkastellut ongelmaa sekä EU:n että Suomen näkökulmasta. Euroopan parlamentin ja neuvoston direktiivi 94/62/EY vuodelta 1994 velvoittaa tehostamaan nimenomaan pakkausjätteiden kierrätystä. Valtioneuvoston päätös vuodelta 1997 antaa ohjeet ja velvoitteet Suomen osalle. Suomessa ollaan tiettyjen kierrätysmenetelmien kohdalla aivan Euroopan kärkimaita. Pakkausjätteiden hyödyntäminen on ainoa järkevä ja kestävä vaihtoehto, koska se vähentää ympäristöhaittoja ja pakkausjätteiden määrää.
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(University of HelsinkiHelsingin yliopistoHelsingfors universitet, 2007)In Finland, most meat products are marinated, packaged under modified atmosphere (MA) and cold-storaged at temperatures below 6 °C. Marinades contain many additives such as spices and dried onion products. It has not been investigated whether these onion products are a source of spoilage bacteria typically associated with MA-packaged, cold-storaged meat products. Organisms that may cause spoilage in MA-packaged, cold-storaged meat products are mainly lactic acid bacteria and some enterobacteria. The majority of dried onion products used in Finland originate from few sources. Therefore, problems in the microbial quality of the onion products would have a widespread influence on the quality of Finnish meat products. We studied 30 samples of dried onions; onion powders, onion granules, onion grains and garlic powders. Lactic acid bacteria plate counts were determined on MRS-amfoterisin-B-agar and 193 lactic acid bacterium isolates were characterized by using a library employing 16S and 23S rRNA gene HindIII RFLP patterns as operational taxonomic units in numerical analyses. Enterobacterial plate counts were determined on VRBG-agar. All samples were incubated at 25 °C. Lactic acid bacterium levels varied between 6.7×103 to 4.4×106 CFU/g. Enterobacterial counts were more than 10 CFU/g in only 7 samples of 30, and their plate levels varied between 2.0×101 to 6.0×102 CFU/g. Of the 193 isolates, 34.7 % were identified as Weissella confusa, 35.8 % Weissella cibaria, 8.3% Enterococcus faecium and 6.2 % Pediococcus acidilactici. In addition, 5 isolates were characterized as Leuconostoc citreum and 2 as Lactobacillus plantarum. Lactobacillus brevis, Leuconostoc pseudomesenteroides and Weissella paramesenteroides were also detected. Out of 193 isolates 19 remained unidentified. Neither W. confusa nor W. cibaria, that were the main species identified in the onion samples, have been shown to cause spoilage in MA-packaged, cold-storaged meat products. None of the other LAB species that were identified in this study have been shown to cause spoilage in these products either. Because the enterobacterial levels in the onion products were low, we also conclude that dried onions cannot be considered as a source of psycrotrophic enterobacteria.
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(University of HelsinkiHelsingin yliopistoHelsingfors universitet, 2009)The quality of easily spoiling minced meat is regularly inspected by food control authorities. The quality of minced meat near the sell-by date has often been found to be poorer than could be wished for. In previous studies psychrotrophic lactic acid bacteria have been found to be significant spoilage bacteria in modified atmosphere packed meat but the spoilage bacteria of minced meat have not been studied. An industrial manufacturer delivered 20 packages of modified atmosphere packed minced meat which were studied on the sell-by day (±1 day). The concentrations of lactic acid bacteria and enterobacteria in the minced meat samples were quantified on MRS agar and VRBG agar respectively. The appearance and smell of raw minced meat was judged organoleptically. 349 lactic acid bacteria isolates were identified using ribotyping based on numerical analysis. The DNA of the lactic acid bacteria was isolated and digested with the restriction enzyme HindIII. The DNA fragments were separated by agarose gel electrophoresis and transferred to a nylon membrane where the fragments were hybridized with a labelled probe. Thus the ribopatterns of the isolates could be visualised on the membrane. The ribopatterns were compared with corresponding patterns in the research group's database which comprises the ribopatterns of over 7000 strains. Identification of the isolates is based on the locations of type strains in the clusters created in the numerical analysis according to similarity of ribotypes. The lactic acid bacteria counts in the minced meat samples were 1,1 × 107 – 4,9 × 108 cfu/g (on average 1,9 × 108 cfu/g). Enterobacterial counts were 9,0 × 102 – 9,0 × 104 cfu/g (on average 1,4 × 104 cfu/g). Observations in the sensory evaluation included grayness and off-odours of varying strength. The off-odours were described as rancid and buttery. The most common species of lactic acic bacteria were identified to be Leuconostoc gasicomitatum (58 % of lactic acid bacteria isolates) and Leuconostoc gelidum (20 %). Other species were Carnobacterium divergens (10 %), Carnobacterium maltaromaticum (4 %), Lactococcus spp. (3 %), Leuconostoc mesenteroides (2 %), Lactobacillus algidus (1 %), Lactobacillus sakei (1 %), and Leuconostoc carnosum (1 %). In addition to these, 15 isolates were identified as Brochothrix thermospacta which appeared to grow on MRS along with lactic acid bacteria. Lactic acid bacteria, especially L. gasicomitatum and L. gelidum, were recognised as the spoilage bacteria of industrially manufactured, modified atmosphere packed minced meat. These organisms have been shown to grow on modified atmosphere packed meat during cold storage and to be connected with the formation of sour and buttery off-odours. L. gasicomitatum and L. gelidum are not part of the natural microbiota of slaughter animals and therefore the significance of the production environment as their source should be examined.
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