Attenuated Lactococcus lactis and Surface Bacteria as Tools for Conditioning the Microbiota and Driving the Ripening of Semisoft Caciotta Cheese

Abstract

This study aimed at establishing the effects of attenuated starters and surface bacteria on various features of caciotta cheese. The cheese undergoes a ripening period during which the house microbiota contaminates the surface. Conventional cheese (the control cheese [CC]) is made using only primary starters. Primary starters and attenuated (i.e., unable to grow and synthesize lactic acid) Lactococcus lactis (Lc. lactis) subsp. lactis were used to produce caciotta cheese without (ATT cheese) or with an inoculum of surface bacteria: (i) Leuconostoc lactis (Le. lactis) (LL cheese), (ii) Vibrio casei (VC cheese), (iii) Staphylococcus equorum (SE cheese), (iv) Brochothrix thermosphacta (BX cheese), and (v) a mixture of all four (MIX cheese). Attenuated Lc. lactis increased microbial diversity during cheese ripening. At the core, attenuated starter mainly increased indigenous lactococci and Lactobacillus delbrueckii group bacteria. At the surface, the main effect was on Macrococcus caseolyticus. Autochthonous Le. lactis strains took advantage of the attenuated starter, becoming dominant. Adjunct Le. lactis positively affected Lactobacillus sakei group bacteria on the LL cheese surface. Adjunct V. casei, S. equorum, and B. thermosphacta did not become dominant. Surfaces of VC, SE, and BX cheeses mainly harbored Staphylococcus succinus. Peptidase activities were higher in cheeses made with attenuated starter than in CC, which had the lowest concentration of free amino acids. Based on the enzymatic activities of adjunct Le. lactis, LL and MIX cheeses exhibited the highest glutamate dehydrogenase, cystathionine-␥-lyase, and esterase activities. As shown by multivariate statistical analyses, LL and MIX cheeses showed the highest similarity for microbiological and biochemical features. LL and MIX cheeses received the highest scores for overall sensory acceptability. IMPORTANCE This study provides in-depth knowledge of the effects of attenuated starters and surface bacterial strains on the microbiota and related metabolic activities during cheese ripening. The use of attenuated Lc. lactis strongly impacted the microbiota assembly of caciotta cheese. This led to improved biochemical and sensory features compared to conventional cheese. Among surface bacterial strains, Le. lactis played a key role in the metabolic activities involved in cheese ripening. This resulted in an improvement of the sensory quality of caciotta cheese. The use of attenuated lactic acid bacteria and the surface adjunct Le. lactis could be a useful biotechnology to improve the flavor formation of caciotta cheese.

Use of Exopolysaccharide-Synthesizing Lactic Acid Bacteria and Fat Replacers for Manufacturing Reduced-Fat Burrata Cheese: Microbiological Aspects and Sensory Evaluation

“…S. thermophilus , used as starter E1 in the RCE1, RCE1-2, RCXE1, and RCCE1 Burrata cheeses, was one of the dominant OTUs in the control, RC, and RCE1-2 Burrata cheeses. Dominance of S. thermophilus in Burrata cheeses manufactured without starter E1 is probably due to contamination from dairy environment, in agreement with previous studies on cheeses manufactured at the same dairy plant used in this study [ 4 , 68 , 69 ]. Notwithstanding the high relative abundance of Pseudomonas sp.…”

“…lactis , Lc. lactis , and Macrococcus caseolyticus ) were in agreement with co-occurrence patterns observed for Caciotta cheese manufactured at the same dairy plant [ 69 ].…”

Modelling the biphasic growth of non-starter lactic acid bacteria on starter-lysate as a substrate

“…While Lactococcus lactis serves as the starter lactic acid bacteria (SLAB) for the manufacture of many cheese types, Lactobacilli constitute the majority of NSLAB in long time ripened cheeses (Broadbent et al, 2013;Calasso et al, 2020;Gobbetti et al, 2015).…”

Influence of Autochthonous Putative Probiotic Cultures on Microbiota, Lipid Components and Metabolome of Caciotta Cheese

“…On the other hand, pasteurization causes the loss of indigenous LAB species relevant for fermentation and ripening process. Therefore, in order to standardize the production while preserving at the same time the unique characteristics of this typical cheese variety, the addition of selected autochthonous adjunct cultures appears as a most efficient tool, as reported in other studies (Fusco et al, 2019;Bancalari et al, 2020;Calasso et al, 2020). The use of autochthonous starter cultures has already been proved to be an effective mean for standardizing the production of raw milk cheeses at the same time positively affecting their quality (Silvetti et al, 2017;De Pasquale et al, 2019;Dolci et al, 2020).…”