1. Bacterial community of industrial raw sausage packaged in modified atmosphere throughout the shelf life
- Author
-
Fausto Gardini, Alessandro Ulrici, Alberto Amaretti, Tiziana Maria Sirangelo, Chiara Montanari, Maddalena Rossi, Maria Rosaria Nappi, Rudy Magnani, Giulia Tabanelli, Alan Leonardi, Stefano Raimondi, Raimondi, Stefano, Nappi, Maria Rosaria, Sirangelo, Tiziana Maria, Leonardi, Alan, Amaretti, Alberto, Ulrici, Alessandro, Magnani, Rudy, Montanari, Chiara, Tabanelli, Giulia, Gardini, Fausto, and Rossi, Maddalena
- Subjects
0301 basic medicine ,Brochothrix ,Firmicutes ,Aerobic bacteria ,030106 microbiology ,Colony Count, Microbial ,Shelf life ,Microbiology ,03 medical and health sciences ,Volatile Organic Compound ,Food Preservation ,RNA, Ribosomal, 16S ,Lactobacillus ,Animals ,Lactic Acid ,Food science ,Meat Product ,Acetic Acid ,Volatile Organic Compounds ,Spoilage ,Bacteria ,biology ,Animal ,Chemistry ,Microbiota ,Food Packaging ,Sausage ,General Medicine ,Lactobacillaceae ,biology.organism_classification ,Random Amplified Polymorphic DNA Technique ,Meat Products ,Food Storage ,Leuconostoc mesenteroides ,Modified atmosphere ,16S rRNA gene profiling ,MAP ,Food Microbiology ,Raw meat ,Leuconostoc carnosum ,Food Science - Abstract
Ten lots of industrial raw sausages in modified atmosphere (CO2 30%, O2 70%), produced in the same plant over 7 months, were analyzed at the day after production (S samples) and at the end of shelf life (E samples), after 12 days storage at 7 °C to simulate thermal abuse. Quality of the products was generally compromised by storage at 7 °C, with only 3 E samples without alterations. During the shelf life, the pH decreased for the accumulation of acetic and lactic acids. A few biogenic amines accumulated, remaining below acceptable limits. The profile of volatile compounds got enriched with alcohols, ketones, and acids (e.g. ethanol, 2,3-butanediol, 2,3-butandione, butanoic acid) originated by bacterial metabolism. Throughout the shelf life, aerobic bacteria increased from 4.7 log to 6.6 log cfu/g, and lactic acid bacteria (LAB) from 3.7 to 8.1 log cfu/g. Staphylococci, enterobacteria, and pseudomonads passed from 3.7, 3.0, and 1.7 to 5.5, 4.8, and 3.0 log cfu/g, respectively. Dominant cultivable LAB, genotyped by RAPD-PCR, belonged to the species Lactobacillus curvatus/graminis and Lactobacillus sakei, with lower amounts of Leuconostoc carnosum and Leuconostoc mesenteroides. Brochothrix thermosphacta was the prevailing species among aerobic bacteria. The same biotypes ascribed to several different species where often found in E samples of diverse batches, suggesting a recurrent contamination from the plant of production. Profiling of 16S rRNA gene evidenced that microbiota of S samples clustered in two main groups where either Firmicutes or Bacteroidetes prevailed, albeit with taxa generally associated to the gastro-intestinal tract of mammals. The microbial diversity was lower in E samples than in S ones. Even though a common profile could not be identified, most E samples clustered together and were dominated by Firmicutes, with Lactobacillaceae and Listeriaceae as the most abundant families (mostly ascribed to Lactobacillus and Brochothrix, respectively). In a sole E sample Proteobacteria (especially Serratia) was the major phylum.
- Published
- 2018