• The Application of On-line Sensors and Novel Control Technologies for Food Processing

      O'Callaghan, Donal; O'Donnell, Colm P.; Mulholland, E.; Duffy, Arthur (Teagasc, 1999-02-01)
      The objective of this research was to apply on-line continuous sensors in food processing, in particular in cheese and milk powder manufacture, in order to improve process control, for example, by achieving higher quality, increased yields, reduced losses and less downgrading of product. This project focused on technologies for monitoring rheologyrelated parameters. The main conclusions were as follows: * Seven systems for monitoring curd formation in cheesemaking were evaluated in the laboratory. * Two on-line systems for monitoring curd firmness (hot-wire and NIR reflectance) have been deployed in a commercial cheese plant with promising results. * Experimental results demonstrated that NIR reflectance / transmission probes have a potential for on-line application in cheesemaking. Despite the difference in scale, the commercial sensors compared well with the cheesemaker s observation of curd firming and look promising as an objective means of predicting curd cut time in an industrial cheese plan. * A detailed knowledge of the rheological variation in cheese curd has been developed and a means of investigating factors which influence the rheology of cheese curd (e.g. effect of heat treatment or fortification of cheesemilk) has been determined. * Technologies available for monitoring concentrate viscosity changes in the production of milk powder have been assembled at pilot scale, and initial trials have been encouraging. Further evaluation of the MTL plant to assess on-line performance, ruggedness and cleanability are planned.
    • Improved Food Safety through Sterility of Air in Food Processing and Packaging.

      O'Callaghan, Donal; Murphy, P.; Lynch, Denise B; Coleman, S. (Teagasc, 1999-06-01)
      The aims of this research were to develop reliable methods for evaluating the level of airborne micro-organisms in food processing facilities and to study the viability and behaviour of micro-organisms in air filtration systems. The main conclusions were as follows: · Assessment of air quality involves monitoring both particulate and microbial levels as there is no simple relationship between these phenomena in a food process environment. · The large fluctuations in microbial levels found in air in these studies underline the necessity of frequent and regular air sampling in processing facilities. · It was established that micro-organisms can grow inside an air filter under certain environmental conditions and give rise to intermittent microbial germ contamination of the cleaned air. · It was demonstrated that flowing air affects the survival of microorganisms and the survival rate is dependent on filter class. Hence more emphasis on filter design aimed at effective microbial control is advised. · A combined system for filtering and sterilisation by ozone was demonstrated to be an efficient technique for extending the microbial separation efficiency of air filters.
    • On-line Sensor Control for Milk Powder and Cheese Manufacture.

      O'Callaghan, Donal; Schulz, Daniela; O'Donnell, Colm P.; Duffy, Arthur; Hade, John; Howard, Vincent (Teagasc, 2001-08-01)
      This project investigated the use of on-line sensors of rheological characteristics which can be measured during the manufacture of milk powder and cheese. The objective is to use on-line measurements to fine tune each process, so as to compensate for the variability of milk.