Inhibition of Aspergillus carbonarius growth and Ochratoxin A production using lactic acid bacteria cultivated in an optimized medium.

The Gram-positive bacteria lactic acid bacteria (LAB) are used in the food industry but are also known for inhibiting certain food spoilage microorganisms, especially fungi. Sources of nitrogen (N) for culture media are generally organic and expensive. Many attempts have been made to formulate economical culture media with alternative N sources obtained from agricultural and industrial byproducts. This study describes the design and optimization of an inexpensive culture medium for Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) MZ809351 strain B31. The culture medium was optimized using statistical experimental designs to identify the factors with the most significant effects on biomass concentration to reduce the overall cost, aiming to obtain a biomass concentration similar to that obtained with the reference LAB culture medium (de Man, Rogosa and Sharpe; MRS). Sodium acetate and magnesium sulfate were the most significant factors (p < 0.005), and their contents were reduced by 22 % and 40 %, respectively, without affecting biomass concentration. Malt germ extract (MGE) was used as an alternative nitrogen source to replace meat extract (ME) and proteose peptone (PP). Through these experiments, the composition of a culture medium that is less expensive than MRS broth was defined, which produced a biomass concentration (3.8 g/L) similar to that obtained with MRS medium. The inhibitory effects of two LAB strains isolated from the Ivory Coast and Mexico on the growth and production of ochratoxin A (OTA) in an ochratoxigenic fungus was tested. The minimum cellular concentration of the LAB to prevent the development of Aspergillus carbonarius Ac 089 and the production of OTA was determined in a model assay in Petri dishes. The conditions to inhibit the germination of A. carbonarius Ac 089 and the production of OTA were found. Using the optimized medium and a ratio of 2 × 104 LAB/spore (1 × 108 CFU/mL) strain B7 (L. plantarum MZ809351) and 2 × 103 LAB/spore (1 × 107 CFU/mL) strain B31 (L. plantarum MN922335) completely inhibited the growth of the fungus. A ratio of 2 × 105 LAB/spore (1 × 109 CFU/mL) was required to inhibit OTA production with strains B7 and B31. This study indicates the potential of cultivating LAB in an optimized and inexpensive culture medium for use as a biological control agent against ochratoxigenic fungi in food.

Partial laryngectomy as salvage surgery after radiotherapy: oncological and functional outcomes and impact on quality of life. A retrospective study of 20 cases.

UNLABELLED: The gold standard for the management of laryngeal squamous cell carcinoma in a previously irradiated patient is "salvage" total laryngectomy, but surgical management by partial laryngectomy can sometimes be proposed in selected patients. OBJECTIVES: This study was designed to review the functional and oncological outcomes of patients treated by open partial laryngectomy for recurrent squamous cell carcinoma after failure of radiotherapy or involving previously irradiated tissues and to define prognostic criteria for the selection of patients eligible for this treatment strategy. MATERIALS AND METHODS: In this retrospective study, 20 patients underwent partial laryngectomy between 2000 and 2011 for recurrence or second primary stage I or II laryngeal squamous cell carcinoma in an irradiated territory (11 vertical partial laryngectomies; 9 horizontal partial laryngectomies). RESULTS: The 3-year overall survival rate in patients with negative resection margins was 66%, with higher survival rates for tumours confined to the glottis, and the 2-year local control rate was 67%. Positive resection margins requiring total laryngectomy were observed in 20% of cases. The 3-year overall survival rate was 56% in these patients. Exclusive oral feeding was restored in 75% of patients after an average of 32 days. The tracheotomy tube was removed after an average of 18 days in 90% of patients. The disease-free functional larynx preservation rate was 45%. CONCLUSIONS: Salvage partial laryngectomy in irradiated tissues is an alternative treatment option to total laryngectomy in selected patients.

Effect of operating conditions on ochratoxin A extraction from roasted coffee.

Operating conditions affect ochratoxin A (OTA) extraction from roasted coffee. The OTA content found in the beverage can thus be greater than that found in the roasted coffee used to prepare it. Three extraction parameters were studied for roasted coffee: type of extraction solvent (alkaline, neutral, acid), temperature (ambient temperature/23 degrees C, 60 degrees C and 85 degrees C), and extraction time (5, 20, 30, 40, 50, 60 and 80 min). The alkaline solvent used in the method recommended by the European Union extracted OTA better, but a maximum content was obtained at 60 degrees C after 50 min. At least a 100% improvement in extraction was obtained when compared with the European Union usual quantification method that is carried out at ambient temperature. It turned out that the OTA extraction parameters for roasted coffee, as defined by that method, were not optimum and needed to be modified. These results were verified in double-extraction experiments showing that OTA is not completely extracted by this method. Confirmation was obtained by comparison of extraction methods on several commercial samples of roasted coffee.