Incorporation of microbiological and molecular methods in HACCP monitoring scheme of molds and yeasts in a Greek dairy plant: A case study

Abstract

Yogurt and yogurt based products are widely consumed globally within European countries. The main microbiological spoilage problems occur from acid tolerant yeasts and molds. The prevention and /or reduction of such contamination is a major objective of HACCP. One of the prerequisite control points is the microbiological air quality of the facility. A one year prospective study of fungal air contamination was conducted in one outdoor and two indoor areas, in a Greek dairy plant. Air was sampled with a portable air system impactor and identified mainly through classical microbiological methods and molecular typing techniques. During the period of survey, the mean viable fungal load was 362.3 CFU/m3 in outdoor air samples and 69.8 CFU/m3 and 266.2 CFU/m3 in samples from the two indoor locations. The three dominant fungal genus recovered were Cladosporium spp., Penicillium spp. and yeasts. Seasonal variations observed in all locations were examined and corrective actions were applied to reduce the fungal load, in one of the interior areas. HEPA air filters were installed and a twenty time reduction (from 69.8 to 3.5 CFU/m3) was achieved concerning the total fungal load. Implementation of a constant monitoring of the air quality and the recognition, as a critical control point (CCP) led to lower fungal air load, furthermore enhancing the microbiological quality and safety of the products.