Correction to: Modeling the inactivation of Lactobacillus brevis DSM 6235 and retaining the viability of brewing pitching yeast submitted to acid and chlorine washing.

There is an error in the original publication of this paper for the below data was missed by author. It should be under "Conflict of interest" statement.

Inactivation kinetics of beer spoilage bacteria (Lactobacillus brevis, Lactobacillus casei, and Pediococcus damnosus) during acid washing of brewing yeast.

This work aimed to estimate the inactivation kinetic parameters of four potential beer spoilage bacteria (Lactobacillus brevis DSM 6235, Lactobacillus casei ATCC 334, Pediococcus damnosus DSM 20289 and Pediococcus damnosus ATCC 29358) inoculated in brewing yeast submitted to acid washing with purposes of yeast recycle. The experiments were conducted at 4 °C in solutions with pH 1.5, pH 2, and pH 3 adjusted employing 85% phosphoric acid. The acid washing treatment of brewing yeasts in the most common pH used (pH 2.0) demanded almost 50 min for the first decimal reduction (δ) of L. brevis DSM 6235. Sensible strains to acid washing such as P. damnosus DSM 20289 demanded almost 70 min for 4 log reductions to be achieved. On the other hand, pH reduction of the acid washing from 2.0 to 1.5 allowed 4 log reduction of L. brevis DSM 6235) to be obtained in less than 50 min, without ruining brewer's yeast viability. Acid washing in pH 1.5 is a viable method for the inactivation of bacterial contaminants of brewing yeasts. Recycling of brewing yeasts through this approach may contribute to a more sustainable and environmental-friendly industry.

Modeling the inactivation of Lactobacillus brevis DSM 6235 and retaining the viability of brewing pitching yeast submitted to acid and chlorine washing.

This study aimed to model the inactivation of Lactobacillus brevis DSM 6235 while retaining the viability of yeasts during washing brewer's yeast with phosphoric acid and chlorine dioxide. The independent variables in the acid washing were pH (1-3) and temperature (1-9 °C), whereas in the washing with chlorine dioxide, concentration (10-90 mg/L) and temperature (5-25 °C) were assessed. The predictive models obtained for the four response variables γLA, γCl (decimal reduction of L. brevis DSM 6235), Vf/V0LA, and Vf/V0Cl (brewer's yeast viability ratio) were found to have R2 > 0.80 and values of Fcalc > Freference. Then, the models were considered predictive and statistically significant (p < 0.10). Our results indicated that phosphoric acid and chlorine dioxide washing resulted in up to 7 and 6.4 (log CFU/mL) decimal reductions of L. brevis DSM 6235, respectively. On the other hand, the viability of the brewer's yeast ranged from 22.3 to 99.4%. L. brevis DSM 6235 inactivation was significantly influenced by parameters pH(Q) and T°C(Q) when phosphoric acid was applied, and by parameters mg/L(L), mg/L(Q), T°C(Q), and mg/L × T°C when ClO2 was applied. The validation of the models resulted in bias (γLA, 0.93/Vf/V0LA, 0.99 - γCl, 1.0/Vf/V0Cl, 0.99) and accuracy values (γLA, 1.12/Vf/V0LA, 1.01 - γCl, 1.08/Vf/V0Cl, 1.03). The results of this study indicate that it might be possible to decontaminate brewer's yeast through acid and chlorine dioxide washing while keeping its viability. This procedure will result in the reduction of costs and the lower generation of brewer's waste.