Caracterização do potencial tecnológico bioconservante de culturas nativas para uso em produto lácteo caprino fermentado

Abstract

The present study was divided into three stages. In the stage 1, the in vitro inhibitory capacity of native lactic bacteria, Lacticaseibacillus rhamnosus EM1107, Lactiplantibacillus plantarum (CNPC001, CNPC002, CNPC003, CNPC004 and CNPC020), and Limosilactobacillus mucosae CNPC007, was evaluated on the reference strains of contamination microorganisms Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, and Salmonella enterica serovar Typhimurium ATCC 14028 in solid media traditionally used for the enumeration of these microorganisms in food. In stage 2, L. plantarum CNPC001 was selected, due to its remarkable ability to inhibit the Salmonella strain, to assess its antimicrobial potential in fermented raw goat milk against contamination indicators (E. coli, S. aureus, and Salmonella spp.). To do this, two distinct treatments were produced in triplicate in raw goat milk, one only with the starter Streptococcus thermophilus and the other with the starter and L. plantarum CNPC001 in co-culture. In stage 3, the stability of a beverage produced with thermally treated goat milk fermented with S. thermophilus and L. plantarum CNPC001 in co-culture, enriched with inulin and honey. In the last two stages, the products underwent physical-chemical and microbiological evaluations, with only stage 3 determining the proximate composition and sensory evaluation. The results of stage 1 revealed that L. plantarum CNPC001 outperformed the contamination indicators. Thus, this microorganism was selected to continue the studies in food matrices, both in raw goat milk (stage 2) and in fermented goat dairy products (stage 3). When incorporated into the food matrix, L. plantarum CNPC001 demonstrated a significant bio-preservative effect, inhibiting the growth of E. coli, S. aureus, and Salmonella spp. while maintaining adequate viability, above 7 log CFU g-1 , in both raw goat milk and fermented dairy beverage. The fermented goat milk beverage exhibited microbial parameters and composition within the limits established by Brazilian regulations, particularly sanitary indicators, lactic acid bacteria and protein content, nutrient this with appropriate levels for this food product classification. This product achieved good overall sensory acceptance, with scores above 8.9 on a scale from 0 to 10. In conclusion, the combination of inulin, honey, and the potentially probiotic native culture L. plantarum CNPC001 in co-culture with S. thermophilus shows to be promising in functionally enriching goat milk and aiding in its preservation.