Effects of wild type lactic acid bacteria on histamine and tyramine formation in sucuk

Biogenic amines (BAs) are formed by the decarboxylation of amino acids in fermented products and accumulate in these products due to the fermentation conditions, the natural microflora of the product, and the diversity of amino acids. Although they are inhibited by the human body, they are a hazard to public health. Starter cultures used in fermented sucuk should not have amino acid decarboxylase properties. The aim of the present study was to determine proteolytic activity, histidine and tyrosine decarboxylase enzyme activities of Lactobacillus plantarum, Lactobacillus sake, and Lactobacillus curvatus species and to evaluate the level of BA in sucuk groups containing these lactic acid bacteria (LAB). It was determined that none of the LAB generated these activities. While histamine values were not statistically significant in the sucuk groups (P> 0.05), tyramine values showed statistically significant differences (P<0.05). The tyramine values of GI ( = 1.43 ± 0.75) and GIII ( = 2.73 ± 1.02) groups were lower than C ( = 8.97 ± 5.29) and GII ( = 7.58 ± 2.90) groups. According to the results of the study, L. plantarum or L. curvatus can provide more reliable fermented products with respect to tyramine formation. L. plantarum, L. sake, and L. curvatus could reduce histamine and tyramine formation in fermented sucuk.

Study on Lactobacillus Isolation from Rabbit Meat Sausage and its Fermentation Property

Three lactobacilli (L26, L34 , L106) isolated from naturally fermented rabbit sausage in a traditional way are identified as lactobacillus plantarum, lactobacillus sake and lactobacillus fructosus. Further study of its fermentation property shows that three lactobacilli are effective in acid production, alkali resistant, nitrite resistant and bacteriostatic, and are antagonisticaction free, which can be used as combined rabbit meat starter.

Modelling antagonic effect of lactic acid eacteria supernatants on some pathogenic bacteria

This work presents a statistical model of survival analysis for three pathogenic bacterial strains (Escherichia coli, Listeria monocytogenes and Staphylococcus aureus), when treated with neutralized and non-neutralized filtered supernatants broth from cultures of Lactobacillus acidhophilus, Lactobacillus rhamnosus and Lactobacillus sake. Survival analysis is a method employed to determine the period of time from an initial stage up to the occurrence of a particular event of interest, as death or a particular culture growth failure. In order to evaluate the potential efficacy of the ahead mentioned lactic acid bacteria when used as bioprotective starters in foods, experimental data were statistically treated and expressed by simple representative curves. Following the methodology of Cox and Kaplan-Meier, it was possible to make the selection of the best bioprotective lactic starter, as a predictive tool for evaluation of shelf life and prevention of eventual risks in fresh sausages and other similar food products.

Influence of Calcium Lactate on the Fate of Spoilage and Pathogenic Microorganisms in Orange Juice

Calcium lactate is used by the beverage industry as a source of calcium to fortify fruit juice. The objective of this study was to evaluate the influence of various concentrations of calcium lactate on the fate of pathogenic and spoilage microorganisms in orange juice. Commercial nonfortified orange juice was supplemented with calcium lactate at a concentration equivalent to 0, 5, 10, 15, 20, 25, or 30% dietary reference intake. The pH of each fortified juice was adjusted to 3.6 or 4.1. The prepared juice samples were inoculated separately with a three-strain mixture of salmonellae, a three-strain mixture of spoilage yeasts, and three single strains of spoilage bacteria including Alicyclobacillus acidoterrestris, Lactobacillus plantarum, and Lactobacillus sake. The contaminated juice was stored at 4 and 10°C, respectively, for 6 to 7 weeks and assayed once a week for populations of salmonellae, spoilage yeasts, or spoilage bacteria. The results indicated that A. acidoterrestris was inhibited in all juice stored at 4°C and low-pH juice stored at 10°C. The bacterium, however, was able to grow at 10°C in the high-pH juice with calcium lactate concentrations equivalent to 0 and 5% dietary reference intake. The cells of L. sake declined and eventually died off in low-pH juice stored at 4 and 10°C and in high pH stored at 4°C. But the organism flourished at 10°C in the high-pH juice containing 0, 10, and 20% dietary reference intake of calcium lactate. The populations of L. plantarum remained approximately stable in low- as well as in high-pH juice stored at both 4 and 10°C. While inhibited at 4°C, the spoilage yeasts grew at 10°C. Salmonellae died off in all juice stored at 4°C and in low-pH juice stored at 10°C. However, they persisted in the high-pH juice stored at 10°C except in the samples that contained 20 to 30% dietary reference intake of calcium lactate.