Dairy products are characterized by reduced shelf life because they are an excellent growth medium for a wide range of microorganisms. For this reason, it is important to monitor the microbiological quality of dairy products and, in particular, the total viable count and concentration of Escherichia coli, as they are indicators of the hygienic state of these products. In addition, in dairy products such as Mozzarella cheese, it is important to monitor the concentration of lactic acid bacteria (LAB), as they are the major components of starter cultures used in cheese production, contributing to the taste and texture of fermented products and inhibiting food spoilage bacteria by producing growth-inhibiting substances. For these reasons, to ensure the quality and safety of their products, cheese makers should monitor frequently, during fresh cheese production, the concentration of LAB and spoilage bacteria. However, usually, small- to medium-size dairy factories do not have an internal microbiological laboratory and external laboratories of analysis are often too expensive and require several days for the results. Compared with traditional methods, the microbiological survey (MBS) method developed by Roma Tre University (Rome, Italy) allows faster and less-expensive microbiological analyses to be conducted wherever they are necessary, without the need for a microbiological laboratory or any instrumentation other than MBS vials and a thermostat. In this paper, we report the primary validation of the MBS method to monitor LAB concentration in Mozzarella cheese and the analysis, using the MBS method, of total viable count, E. coli, and LAB concentrations in the production line of Mozzarella cheese as well as during the shelf life of the product stored at 20°C. The results obtained indicate that the MBS method may be successfully used by small- to medium-size dairy factories that do not have an internal microbiological laboratory. Using the MBS method, these dairy factories can monitor autonomously the microbiological safety and quality of their products, saving both time and money.

No abstract

No abstract

The results obtained demonstrate that the MBS point-of-care testing (POCT) device could be developed into a valuable aid for the management of UTIs, possibly addressing more precise diagnosis and appropriate therapy.

Standardized microbiological methods used in clinical analysis are based on traditional microbial enrichment on selective media, possibly followed by characterization of bacteria with molecular methods. These techniques present several difficulties, such as the subjectivity in the interpretation of genetic, biochemical or morphological tests and the possible interference of biological matrices, specially when low levels of contamination are present. In addition, standardized microbiological analyses are characterised by the high cost of the method, both in terms of labor and supplies, and above all, by the long time needed to obtain definitive results (from 3 to 7 days). These reasons have led to the development and refinement of microbiological POCTs which are now available for several microorganisms, even thought no microbiological POCT was up to now developed for the count of total viable bacteria (TVC) in serum, urine or other biological fluids.MBS srl (a spin-off of Roma Tre University, Rome, Italy) has developed and patented an alternative method for selective counting of bacteria, called Micro Biological Survey (MBS) method. The MBS method is based on colorimetric survey performed in mono-use disposable reaction vials in which samples can be inoculated without any preliminary treatment. The analyses can be carried out by untrained personnel and anywhere they are necessary, without the need for any other instrumentation than a thermostated optical reader that can automatically detect the colour change providing the number of bacteria present into the sample. The MBS method measures the catalytic activity of redox enzymes in the main metabolic pathways of bacteria, allowing an unequivocal correlation between the observed enzymatic activity and the number of viable cells present in the samples. The time required for a color change is inversely related to the log of bacterial concentration; like an enzymatic reaction, the greater the number of bacteria, the faster the color change.The objective of this study was the primary validation, in accord with ISO 13843:2003 (Guidance on validation of microbiological methods), of the quantitative Micro Biological Survey (MBS) method for Total Viable Count (TVC). Validation aims to compare the results obtained with an alternative method, in this case the MBS method, with the results obtained with the reference method. To verify the equivalence between the two methods different parameters were analyzed: selectivity, linearity and accuracy. The validation has shown that the MBS method gives similar results and is in agreement with the reference methods. The MBS method could therefore represent a worthy aid in microbiological analysis as POCT device without replacing the analysis carried out with traditional methods which are very precise though often long and complex.