Do European Standard Disinfectant tests truly simulate in-use microbial and organic soiling conditions on food preparation surfaces?

AIMS: The results from European standard disinfectant tests are used as one basis to approve the use of disinfectants in Europe. The design of these laboratory-based tests should thus simulate as closely as possible the practical conditions and challenges that the disinfectants would encounter in use. No evidence is available that the organic and microbial loading in these tests simulates actual levels in the food service sector. METHODS AND RESULTS: Total organic carbon (TOC) and total viable count (TVC) were determined on 17 visibly clean and 45 visibly dirty surfaces in two restaurants and the food preparation surfaces of a large retail store. These values were compared to reference values recovered from surfaces soiled with the organic and microbial loading, following the standard conditions of the European Surface Test for bactericidal efficacy, EN 13697. CONCLUSIONS: The TOC reference values for clean and dirty conditions were higher than the data from practice, but cannot be regarded as statistical outliers. This was considered as a conservative assessment; however, as additional nine TOC samples from visibly dirty surfaces were discarded from the analysis, as their loading made them impossible to process. Similarly, the recovery of test organisms from surfaces contaminated according to EN 13697 was higher than the TVC from visibly dirty surfaces in practice; though they could not be regarded as statistical outliers of the whole data field. No correlation was found between TVC and TOC in the sampled data, which re-emphasizes the potential presence of micro-organisms on visibly clean surfaces and thus the need for the same degree of disinfection as visibly dirty surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: The organic soil and the microbial burden used in EN disinfectant standards represent a realistic worst-case scenario for disinfectants used in the food service and food-processing areas.

Periodic and non-periodic sleep apnea in premature and fullterm infants.

The sleep states of nine premature infants were observed and concomitant respiration recordings were obtained at 37 and 41 weeks conceptional age. 19 fullterm infants were also studied at 41 weeks conceptional age. Between 37 and 41 weeks significant decreases occurred in the premature infants' percentage of periodic apnea, rate of apnea in active sleep-REM, and length of the longest apneic episode. The premature and fullterm infants at 41 weeks did not differ in the frequency of apneic episodes, but the premature group had shorter episodes. These results provide additional evidence for the difference between premature and fullterm infants in central nervous system organization.