Preservation of Raw Camel Milk by Lactoperoxidase System Using Hydrogen Peroxide Producing Lactic Acid Bacteria

Abstract

This study was conducted to investigate the effect of lactic acid bacteria (LAB) activated lactoperoxidase system (LPs) on keeping quality of raw camel milk at room temperature. Camel milk samples were collected from Errer valley, Babile district of eastern Ethiopia. The level of hydrogen peroxide (H 2 O 2 ) for activation of LPs was optimized using different levels of exogenous H 2 O 2 . Strains of LAB (Lactococcus lactis 22333, Weissella confusa 22308, W. confusa 22282, W. confusa 22296, S. Infatarius 22279 and S. lutetiensis 22319) with H 2 O 2 producing properties were evaluated, and W. confusa 22282 was selected as the best strain to produce H 2 O 2 . Storage stability of the milk samples was evaluated through the acidification curves, titratable acidity (TA), total bacterial count (TBC) and coliform counts (CC) at storage times of 0, 6, 12, 18, 24 and 48 hours. The LP activity and the inhibitory effect of activated LPs were evaluated by growing E. coli in pasteurized and boiled camel milk samples as contaminating agent. Results indicated that the W. confusa 22282 activated LPs generally showed significantly (P < 0.05) slower rates of acidification, lactic acid production and lower TBC and CC during the storage time compared to the non-activated sample. The H 2 O 2 producing LAB and exogenous H 2 O 2 activated LPs in pasteurized camel milk significantly reduced the growth of E. coli population compared to non-activated pasteurized milk. Overall, the result of acid production and microbial analysis indicated that the activation of LPs by H 2 O 2 producing LAB (i.e. W. confusa 22282) maintained the storage stability of raw camel milk. Therefore, it can be concluded that the activation of LPs by biological method using H 2 O 2 producing LAB can substitute the chemical activation method of LPs in camel milk.

Non-Enzymatic Co3O4 Nanostructure-Based Electrochemical Sensor for H2O2 Detection

“…According to publications [79]- [81], for effective milk antibacterial treatment, a minimal H 2 O 2 concentration of 0.01 %, which is equivalent to 2.9 mM, is used. This value significantly exceeds the calculated LOD for our sensor.…”

Impact of Age, Parity and Milking Frequency on Dromedary Camels' Susceptibility to Subclinical Mastitis

“…The only change obtained in Majahem that at age >7 years showed that serum IgG was significantly higher than their corresponding groups at age<7 years that reflect the tendency of SCM characteristic of increased SCC and bacteriological examination. IgG is a part of the immune system that has several biological functions, including antibacterial and anti-inflammatory qualities (Dashe et al 2020). According to Thorsteinsdottir et al (2019), acute inflammation may cause the mammary gland's blood-to-milk permeability barriers to be destroyed, which increases the passive transfer of IgG into milk and causes an increase in IgG output.…”

Evaluation of Somatic Cells Count, Antioxidants and Antimicrobial Proteins in Milk Samples Obtained from Different Breeds of the Dromedary Camel

“…(Yassin et al 2015;El-Fakharany et al 2017). Activation of LPS has been investigated as a potential alternative technique for maintaining milk safety by eliminating pathogenic microbes (Dashe et al 2020;Mohamed and El Zubeir 2020).…”