title: Development of spoilage bacterial community and volatile compounds in chilled beef under vacuum or high oxygen atmospheres.
abstract: Research into microbial community development and metabolism is essential to understand meat spoilage. Recent years have seen the emergence of powerful molecular techniques that are being used alongside conventional microbiology approaches. This enables more accurate studies on meat spoilage. The aim of this study was to investigate the influence of packaging (under vacuum and in high oxygen atmosphere) on the development of microbial communities and metabolic activities at 6 °C by using culture-dependent (cultivation, ribotyping) and culture-independent (amplicon sequencing) methods. At the beginning of shelf life, the microbial community mostly consisted of Carnobacterium and Lactobacillus. After two weeks of storage, Lactococcus and Lactobacillus were the dominant genera under vacuum and Leuconostoc in high oxygen meat packages. This indicates that oxygen favoured the genus Leuconostoc comprising only heterofermentative species and hence potential producers of undesirable compounds. Also the number of volatile compounds, such as diacetyl, 1-octen-3-ol and hexanoic acids, was higher in high oxygen packages than under vacuum packages. The beef in high oxygen atmosphere packaging was detected as spoiled in sensory evaluation over 10 days earlier than beef under vacuum packaging. Leuconostoc gelidum, Lactococcus piscium, Lactobacillus sakei and Lactobacillus algidus were the most common species of bacteria. The results obtained from identification of the isolates using ribotyping and amplicon sequencing correlated, except for L. algidus, which was detected in both types of packaging by amplicon sequencing, but only in vacuum packaged samples using the culture-based technique. This indicates that L. algidus grew, but was not cultivable in high oxygen beef using the Nordic Committee on Food Analysis standard method.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland. Electronic address: Elina.L.Jaaskelainen@helsinki.fi.
authors.forename: Elina
authors.initials: E
authors.lastname: Jääskeläinen
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Jenni
authors.initials: J
authors.lastname: Hultman
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, Helsinki, Finland.
authors.forename: Jevgeni
authors.initials: J
authors.lastname: Parshintsev
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, Helsinki, Finland.
authors.forename: Marja-Liisa
authors.initials: ML
authors.lastname: Riekkola
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Johanna
authors.initials: J
authors.lastname: Björkroth
mesh_terms: D000818:Animals; D001419:Bacteria / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism; D002417:Cattle; D005516:Food Microbiology / Q000379:methods*; D018857:Food Packaging / Q000379:methods* / Q000592:standards*; D008460:Meat / Q000032:analysis / Q000382:microbiology* / Q000592:standards; D010100:Oxygen; D021521:Ribotyping; D014618:Vacuum; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D055549:Volatile Organic Compounds; D010100:Oxygen
keywords: 1-octen-3-ol (PubChem CID: 18827); 16S rRNA amplicon sequencing; 2-octen-1-ol (PubChem CID: 29060); Acetic acid (PubChem CID: 176); Acetoin (PubChem CID: 179); Butanoic acid (PubChem CID: 264); Diacetyl (PubChem CID: 650); Ethanol (PubChem CID: 702); Hexanal (PubChem CID: 6184); Hexanoic acid (PubChem CID: 8892); Lactic acid bacteria; Nonanal (PubChem CID: 31289); Packaged beef; Spoilage; Volatile compounds