Behaviour of Lactobacillus rhamnosus strains in ass’s milk
Authors: R. COPPOLA1,5*, E. SALIMEI2, M. SUCCI1, E. SORRENTINO1,M. NANNI3, P. RANIERI1, R. BELLI BLANES4, L. GRAZIA1
1 Dipartimento di Scienze e Tecnologie Agro-Alimentari, Ambientali e Microbiologiche
2 Dipartimento di Scienze Animali, Vegetali e dell’Ambiente - Università degli Studi del
Molise, Via De Sanctis, 86100 Campobasso, Italy
3 Dipartimento Controllo Qualità P.R., Via J.F. Kennedy 18a, 42100 Reggio Emilia, Italy
4 ASL Brescia, Distr. Salò, Italy
Istituto di Scienze dell’Alimentazione, Via Roma 52 A/C, 83100 Avellino, Italy
Abstract: Aim was to investigate the efficacy of heat treatment on microbiological and
biochemical quality of ass’s milk and its effects on the growth of 4 different strains of Lactobacillus rhamnosus. Milk samples were obtained from 6 machine-milked asses (Martina Franca breed). Low bacterial counts (about 4x104 CFU/mL) were observed in raw milk samples likely due to high levels of lysozyme. The possible role of lysozyme was also suggested by stable pH values during storage for 15 days. Moreover, ass’s milk demonstrated to be a good growth medium for potentially probiotic strains of L. rhamnosus since pH ranged between 3.67 and 3.85 for all the tested strains after a 48-hour period of incubation.
Values were stable up to the end of the trials. Results evidenced that ass’s milk is indeed an excellent candidate for probiotic beverages.