Multi-Functional Potential of Presumptive Lactic Acid Bacteria Isolated from Chihuahua Cheese

Abstract

The multifunctional properties of autochthonous lactic acid bacteria can be of use for enhancing the sensorial properties of food, as well as in food preservation. An initial screening for antimicrobial, proteolytic, and lipolytic capacities was done in 214 presumptive lactic acid bacteria isolates obtained from Chihuahua cheese manufacturing and during a ripening period of nine months. The antimicrobial screening was done by spot-on-the-lawn tests, using Listeria monocytogenes and Escherichia coli as indicator microorganisms; proteolysis was tested in casein-peptone agar and lipolysis in Mann–Rogosa–Sharpe (MRS)-tributyrin agar. More than 90% of the isolates hydrolyzed the casein, but only 30% hydrolyzed tributyrin; the inhibition of L. monocytogenes in the spot-on-the-lawn assay was used to select 39 isolates that had a bigger inhibition zone (>11.15 mm ± 0.3) than the control (Nisin producer Lactococcus lactis BS-10 Chr Hansen). The selected isolates were grown in MRS to obtain the neutralized cell-free supernatants and verify their antimicrobial activity by agar diffusion and the percentage of growth inhibition techniques. The selected isolates were also growth in casein peptone broth, and the cell-free supernatants were used for the determination of antioxidant activity by the radical scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) techniques. The results were analyzed to identify similarities by cluster analysis, based on their antimicrobial and antioxidant capacities. The isolates were arranged into six clusters; one cluster that included 12 isolates demonstrated L. monocytogenes (784–2811 mm2/mL AU by agar diffusion assay) and E. coli (41%–47% growth inhibition) antimicrobial activity. The isolates clustered in these groups also showed competitive inhibition of both radicals (11%–19% of DPPH and 50%–60% of ABTS). The isolates from cluster one were also identified by 16S rDNA amplification and were identified as Enterococcus faecium. Traditional products such as Chihuahua cheese can be a source or lactic acid bacteria with metabolic properties that can be used in food preparation and preservation.

Selection of Lactic Acid Bacteria Isolated from Fresh Fruits and Vegetables Based on Their Antimicrobial and Enzymatic Activities

“…Among the E. faecium identified, PIM4 showed antimicrobial activity against B. cereus, L. monocytogenes (Strongly), the three molds evaluated, as well as S. cerevisiae, and C. tropicalis. E. faecium strains have been reported with antimicrobial activity against B. cereus and E. coli [36] and L. monocytogenes and E. coli [37]. However, E. faecium strains in this research did not inhibit the growth of E. coli.…”

“…Although the results are promising for the use of LAB isolates for post-harvest treatments, the safety of the strains need to be assessed. There are concerns of Enterococcus strains, since some can harbor pathogenic genes [ 37 ]; therefore, before considering the use of the isolates presented here, further studies are needed on the presence and expression of pathogenic traits.…”

“…The methodology used for the screening of antimicrobial activities of LAB isolates has been reported before, being its grater advantage, the screening of a large number of isolates, and indicator microorganisms [ 22 , 23 ]. The microtitration method has also been compared in effectiveness with the agar diffusion agar test, and it was observed that when OD inhibition was larger than 70%, correlated with a positive test in the agar diffusion test [ 37 ]. In the case of the strains reported here, inhibition was lower than 65%, and in the agar diffusion test, there was no clear zone of inhibition, although a decrease in the density of the bacterial lawn was observed.…”

Technological and probiotic potential of autochthonous lactic acid bacteria from spontaneously fermented dromedary milk

“…Azat et al., 2016 and Venegas‐Ortega et al. (2020) reported, respectively, similar DPPH and ABTS radical scavenging activities for LAB strains isolated from traditional cow cheese. In contrast, Ding et al.…”

Effect of Pulsed Electric Fields on the Growth and Acidification Kinetics of Lactobacillus delbrueckii Subsp. bulgaricus

“…The main application of LAB is as starter cultures in the food industry with a wide variety of fermented dairy products, meat, fish, fruit, vegetable, and cereal products [2]. LAB have numerous metabolic characteristics such as the acidification activity, proteolytic activity, synthesis of bacteriocin, and production of exopolysaccharides that contribute to the nutritional value and organoleptic quality and extended the shelf life of food products [3][4][5][6]. The strain Lactobacillus delbrueckii subsp.…”