Effect of different sanitizers on the microbial load and selected quality parameters of “chile de árbol” pepper (Capsicum frutescens L.) fruit

The aim of this work was to evaluate the effectiveness of different substances used as sanitizers for "chile de árbol" (Capsicum frutescens L.) fruit by means of their effect on microbial load as well as on fruit physicochemical and sensory properties. Sodium hypochlorite (100–10,000 mg L−1), hydrogen peroxide (5%), ethanol (70%), nisin (125 mg L−1), and a commercial lineal anionic surfactant (2%) were used to sanitize pepper fruit. Different exposure times were evaluated for selected sanitizers. Ratios of 1:10 of fruit- solutions were utilized for the sanitization processes. After sanitization, microbiological analyses were performed (total mesophilic aerobic bacteria (TMAB), lactic acid bacteria (LAB), molds, and yeasts); in addition, color (L*, a*, b*), texture (peel's break force and peel's hardness), pH, and titratable acidity were determined on pepper fruits. In addition, a sensory evaluation was performed. Medium (1000 and 2000 mg L−1) and high (10,000 mg L−1) sodium hypochlorite concentrations reduced about 2 log10 cycles of TMAB. Molds only were reduced when high concentrations of sodium hypochlorite were used. The most effective sanitizer was ethanol, reducing 4.7 log10 of TMAB, 4.2 log10 of LAB, 2.5 log10 of molds, and 2.7 log10 cycles of yeasts when exposure time was 120 min, and final counts were <100 CFU g−1 for TMAB, and <10 CFU g−1 for LAB, molds, and yeasts. Hydrogen peroxide generated the greatest losses of greenness and texture of treated pepper fruit. The pH increased (ΔpH = 0.2) when high concentrations of sodium hypochlorite were used. The sanitization processes did not affect lightness and titratable acidity. Judges detected losses in greenness of pepper fruits sanitized with hydrogen peroxide (5%, 30 or 120 min), sodium hypochlorite (10,000 mg L−1, 120 min), or ethanol (70%, 30 min); losses in firmness for pepper fruits treated with hydrogen peroxide (5%, 30 min) or nisin (125 mg L−1, 120 min); but noticed increments (p < 0.05) of peppers' pungent smell sanitized with hydrogen peroxide (5%, 30 or 120 min) and sodium hypochlorite (10,000 mg L−1, 120 min). Peppers' brightness did not change (p > 0.05) after treatments.