Evaluation of shelf life was made of cured, cooked, sliced turkey breast fillets and a type of cooked pork sausage called ‘piroski’, stored in vacuum and in six different modified atmospheres (MA) at ...+4 and +10 °C. Total viable count, lactic acid bacteria, pH changes, colour attributes and the presence of pathogenic bacteria (listeriae, staphylococci) were monitored during the storage. The results of the study showed that the average shelf life for both products was 2 and 1 week at 4 and 10 °C, respectively. By the end of these periods, the bacterial population consisting of only lactic acid bacteria reached 10
8 cfu g
−1. Macroscopical (colour, drip loss and slime) and organoleptical changes (sour odours) were not related to pH and observed already at pH values >5.5. It is concluded that the use of MA packaging in these tests did not extend and not reduce the product shelf life in comparison to vacuum packaging.
Lactobacillus curvatus L442, isolated from Greek traditional fermented sausage prepared without the addition of starters, produces a bacteriocin, curvaticin L442, which is active against the pathogen ...Listeria monocytogenes. The bacteriocin was purified by 50% ammonium sulphate precipitation, cation exchange, reverse phase and gel filtration chromatography. Partial N-terminal sequence analysis using Edman degradation revealed 30 amino acid residues, revealing high homology with the amino acid sequence of sakacin P. Curvaticin L442 is active at pH values between 4.0 and 9.0 and it retains activity even after incubation for 5 min at 121 degrees C with 1 atm of overpressure. Proteolytic enzymes and alpha-amylase inactivated this curvaticin, while the effect of lipase was not severe.
The microbiological and physicochemical changes which occurred during the industrial fermentation and ripening of four batches of Greek dry salami manufactured without starter cultures were followed. ...Moderated dehydration rates, monitored by slowly decreasing relative humidity from 94 to 90% during fermentation, prevented the production of insufficiently acidified batches by maintaining microbial activity for longer when the natural inoculum was low. The terminal pH values (5.0–5.2) and water contents (27.7–30.3%) of the sausages were narrowly ranged. Fermentation was governed by an active (>10
8 cfu
g
−1) lactic flora, consisting of `wild' strains of
Lactobacillus sake. Gram-negative bacteria and aerobic sporeformers decreased below 10
2 and 10
3 cfu
g
−1, respectively, while yeasts did not significantly increase during ripening and were below 10
5 cfu
g
−1 in the ripened product. Sausages were substantially free of sulfite-reducing clostridia and coagulase-positive staphylococci during the whole process.
Listeria spp., occurred in the fresh sausage mix, but disappeared from all batches at the latest by the end of fermentation. Enterococci exceeded 10
5 cfu
g
−1 during the first days and remained at this level during ripening. Novobiocin-resistant staphylococci matching
Staphylococcus saprophyticus (mainly) and
S. xylosus dominated Micrococcaceae populations, ranged between 10
5 and 10
6 cfu
g
−1. This is the first report of such a large contribution from
S. saprophyticus to the production of dry salami of good quality. It is concluded that to keep or improve the traditional `sensory type' of Greek salamis, suitable strains of
L. sake, S. xylosus and possibly nitrate-reducing
S. saprophyticus should be selected and validated as starter cultures in experimentally inoculated salamis.
To predict microbial growth during chill storage of a traditional Greek raw sausage, a numerical model was developed and validated. In our novel approach, the specific growth rate of each microbial ...population was calculated on the basis of the main microbial populations grown in the sausage. In addition, the specific destructive effect of the sausage ecosystem was introduced to evaluate microbial growth. The model was integrated by the Runge-Kutta method and the parameter values were optimised by the least squares method. Fitting of the model to the experimental data derived from four sausage batches stored aerobically at 3 and 12°C successfully described the microbial growth kinetics in the sausage niche. Finally, the parameter values estimated by the fitting of the model on the data set from each batch were used to predict microbial growth in the other batches at both storage temperatures.
In an attempt to differentiate between
Weissella viridescens, W. paramesenteroides, W. hellenica and some atypical arginine-negative
Weissella isolates from meats, their cellular fatty acid ...composition was determined by a rapid GC method. Results showed that
W. viridescens synthesized eicosenoic (n-C20:1) acid, while the other two species did not. Meanwhile, unlike
W. paramesenteroides, W. hellenica lacked cyclopropane fatty acids with 19 carbon atoms, i.e. dihydrosterculic or lactobacillic acid.
Weissella viridescens contained zero to low amounts (<1%) of C19 cycl. Original meat isolates identified as
W. viridescens or
W. hellenica shared similar fatty acid profiles with the respective type strains, whereas the “wild” atypical
Weissella isolates resembled more with
W. paramesenteroides, and all together with
Leuconostoc mesenteroides subsp.
mesenteroides. Interesting variations were noted in the total C19 cycl contents among unidentified
Weissella, being generally consistent with their grouping based on the type of lactate they formed and the whole-cell protein profile similarity they shared.
