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THERMAL SANITIZING IN A COMMERCIAL DISHWASHING MACHINE
Author(s) -
NICOLELLA CRISTIANO,
CASINI BEATRICE,
ROSSI FRANCESCO,
CHERICONI ALESSIO,
PARDINI GIANLUCA
Publication year - 2011
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.2010.00270.x
Subject(s) - log reduction , food science , pulp and paper industry , thermal , food contact materials , chemistry , environmental science , food packaging , engineering , physics , meteorology
This paper presents an experimental investigation on the thermal sanitization of food contact surfaces in a pilot dishwashing machine. The reduction of counts for Escherichia coli inoculated on clean glass surfaces was assayed in several tests performed under different conditions of temperature and duration of the washing cycles. The main aim of the measurements was to establish the relationship between operating conditions and sanitizing performance. The experimental results show that reduction of microbial counts clearly increases with the volume of water used for rinsing. On the other hand, the effect of the rinsing water temperature is less remarkable. It is inferred from these results that the reduction of microbial counts on food contact surfaces is mainly due to the mechanical elution of water jets rather than to thermal inactivation. The experimental results are analyzed using available kinetic data for reference organisms. The kinetic analysis confirms that the thermal effect is not sufficient to obtain a significant reduction of microbial counts on food contact surfaces under typical conditions of temperature and washing cycle length. PRACTICAL IMPLICATIONS Unsanitized food contact surfaces can be a direct or indirect source of foodborne illness, as pathogens can be transferred to food from crockery and utensils that are not properly sanitized. Improper cleaning and sanitizing of food contact surfaces is the factor most commonly related to the occurrence of foodborne illness risk in hospital, schools and restaurants. In this work, the effect of the operating conditions on the inactivation of reference microorganism ( Escherichia coli ) was experimentally investigated in a dishwashing machine. The experimental results on the logarithmic reduction on food contact surfaces under different conditions of temperature and contact time show that the microbial reduction in the washing machine is mainly due to the mechanical effect of elution of water jets rather than temperature. The results of this investigation can be used to determine the optimal operating conditions for the washing machine, resulting in the minimum requirement of energy and water.