A model has been produced for predicting the temperature of liquid foods during vacuum cooling. I... more A model has been produced for predicting the temperature of liquid foods during vacuum cooling. It includes a mathematical description of the ingress of ambient air into process equipment, which leads to reduced cooling rates and the potential for contamination of the foodstufj? The model considers the air flow as an adiabatic compressible flow through a nozzle. The model was tested on a full-scale processing vessel containing 500 litres of water or a fruit/sugar preparation used in the production of yoghurts. The temporal trends of total vessel pressure, liquid temperature and the mass of condensed vapour were predicted well. Throughout the period of cooling, the difference bemeen measured and predicted values of pressure did not exceed 19 kPa, the liquid temperature was predicted to within 7°C and the mass of condensed vapour wus predicted to within 5 kg.
International Conference on the Epidemiology and Control of Biological, Chemical and Physical Hazards in Pigs and Pork, 2007
In order to determine typical and atypical operations in the slaughtering and dressing of pigs fo... more In order to determine typical and atypical operations in the slaughtering and dressing of pigs for pork and bacon practices and operations were recorded at eight pig abattoirs. Data included physical parameters such as temperatures and durations. The results indicate that plants are reasonably similar if processing pigs mainly for pork, but those processing mainly for bacon had more aggressive singeing and polishing (black scraper) arrangements. The plants visited used either hot water (tank) or vertical (sprayed hot water) scalding systems prior to dehairing. This study was carried out to establish a microbiological and physical process baseline which would then enable effective existing practices to be identified, as well as identifying those existing, and also novel, practices which have the potential to be developed in order to reduce carcass contamination by Salmonella.
Clinical congestive heart failure (CHF) is a major risk factor for strokes. Patients with CHF com... more Clinical congestive heart failure (CHF) is a major risk factor for strokes. Patients with CHF commonly have atrial fibrillation or flutter (AF), which is frequently associated with, may be a marker for, and may be the mechanism of, ischemic strokes. To determine whether stroke patients with CHF have a high incidence of AF (that may be intermittent and not diagnosed), we reviewed all the 12 lead ECGs in a fourteen year institutional ECG data base and the clinical records and the available echocardiograms of 985 patients who had an ischemic stroke over a 3-year period. We found that 31.3% of the stroke patients had evidence of AF. Clinical congestive heart failure was present in 168 stroke patients; 61.9% of these stroke patients with CHF had evidence of AF. In the total stroke population, patients with other risk factors for stroke (hypertension, advanced age, diabetes, coronary artery disease) had an increased incidence of AF; but among stroke patients with CHF, only advanced age (≥75 years) in addition to CHF increased the incidence of AF. To determine whether only the CHF stroke pts with systolic dysfunction had a high incidence of AF, we compared the incidence of AF in the 41.5% of the CHF patients with a depressed ejection fraction with the AF incidence in the 58.5% of CHF stroke patients with a normal ejection fraction (≥50%). The incidence of AF was the same (63.4% vs. 60.2%, p = 0.741) whether the ejection fraction was depressed or normal. These findings suggest that AF is common in patients with CHF who have strokes whether the ejection fraction is normal or depressed. CHF patients who have strokes and who are in sinus rhythm should be meticulously investigated for intermittent AF, so anticoagulation can be administered to prevent a further stroke.
International Journal of Food Science & Technology, 2017
These studies examined the effects of incorporating bubbles of air in the water used for cleaning... more These studies examined the effects of incorporating bubbles of air in the water used for cleaning surfaces. Small (<50 lm) or large (millimetre) bubbles were used, and these could aid cleaning by a scrubbing action, energy release or free radical production. Small or large bubbles improved the removal of biofilm from steel surfaces by 1.0 log 10 or 1.6 log 10 , respectively. Biofilm removal from a polypropylene pipe wall was improved by 0.9 log 10 by incorporating bubbles into the cleaning water. Further trials showed increased removal of carbohydrate, fat and protein deposits from stainless steel by incorporating bubbles into the water. These results suggest that the use of air bubbles in water could provide small improvements in cleaning or potentially similar contamination removal using less water.
L'invention a trait a un chariot a air sterile, qui comprend un corps mobile possedant au moi... more L'invention a trait a un chariot a air sterile, qui comprend un corps mobile possedant au moins un orifice d'admission d'air dans sa region inferieure et une pluralite d'orifices de sortie d'air dans sa region superieure, et contenant des moyens roues permettant de faire entrer de l'air par ledit orifice d'admission, de le faire passer a travers des moyens de filtrage, et de le faire sortir par les orifices de sortie. La region superieure du corps constitue une surface de travail sensiblement horizontale, caracterisee en ce qu'elle possede une paroi frontiere verticale s'etendant sur son pourtour, de facon que la surface de travail et la paroi frontiere forment un plateau, la paroi frontiere etant creuse. L'air filtre est dirige dans la paroi frontiere et est diffuse a travers les orifices d'admission d'air contenus dans la paroi frontiere, depuis les cotes opposes.
L'objectif de cette etude etait de savoir quelle etait la relation entre le nombre de particu... more L'objectif de cette etude etait de savoir quelle etait la relation entre le nombre de particules aeroportees et le nombre de microorganismes presents dans l'atmosphere des ateliers refrigeres de production alimentaire. Dans quatre ateliers (assemblage de sandwichs, garniture de dessert, pâte et quiche), ont ete effectuees des mesures de concentrations de particules par compteur laser et de concentrations de microorganismes par plaques d'impact. La proportion de particules contenant un microorganismes variait de 1 sur 200 tout pres du personnel se lavant les mains a 1 sur 30 000 dans une usine hygienique en periode de faible activite. Hormis le premier cas ci-dessus, le rapport moyen etait de 1 sur 3 500, mais ce rapport est trop variable d'un cas a l'autre pour que l'on puisse estimer la contamination aeroportee a partir du nombre de particules.
The transfer of contamination through the airborne route is significant in the assembly area of h... more The transfer of contamination through the airborne route is significant in the assembly area of high-care food factories preparing products such as sandwiches, prepared salads and chilled meals. This paper describes equipment designs that have been proposed to restrict such contamination and maintain low air temperatures around the food whilst allowing higher factory temperatures. Designs based on uni-directional flows, open troughs, semi-closed and closed tunnels are described. The uni-directional flow systems have been applied successfully in the chilled food industry although they require higher air flows than the other systems. Troughs offer good maintenance of temperature and low airborne counts around the food. Tunnels are more expensive and there are concerns about clean-ability of the equipment and, with the closed tunnels based on glove-box technology, potential problems of operator comfort.
Many ready-to-eat foods are stored frozen in commercial stores and then defrosted before dispatch... more Many ready-to-eat foods are stored frozen in commercial stores and then defrosted before dispatch to the retail outlet. Large variations in defrost time can reduce product throughput and lead to variable product quality. We propose that defrost rooms be considered as several zones of different heat flux with only small variations in heat flux in each zone. A type of food is located in a particular zone according to the difficulty of defrosting it, and the types and quantities of other foods being defrosted at the same time.
Journal of Physics E: Scientific Instruments, 1981
ABSTRACT The authors describe how a quadratic function in scale reading and a linear function in ... more ABSTRACT The authors describe how a quadratic function in scale reading and a linear function in temperature, over the range 20-90 degrees , adequately represents the flowrate of water measured with a rotameter.
Disinfectants are commonly applied as fogs in the chilled food industry. Recent research has show... more Disinfectants are commonly applied as fogs in the chilled food industry. Recent research has shown that fogging is eective in reducing the number of organisms on upwardfacing surfaces but, in general, it is not eective on vertical or downward-facing surfaces. Fogging also reduces the number of viable airborne organisms, although the reason for this decrease in not understood. Numerical models of the dispersion of airborne particles have been used to simulate the fogging process. These models, with supporting experiments, showed that fogs should be most eective when the median diameter of the fog droplets lies between 10 and 20 mm. Droplets in this size range disperse well and settle within about 45 min. This gives good coverage and the fog clears from the air quickly enough not to pose major disruption to factory operations. #
This study investigated the effectiveness of spraying electrolysed water for reducing the numbers... more This study investigated the effectiveness of spraying electrolysed water for reducing the numbers of Campylobacter on chicken carcasses. Previous studies have used solutions with free chlorine concentrations above 25 ppm and low pH to treat inoculated carcasses. The four trials described here were carried out at process plants treating naturally contaminated, hot, birds with electrolysed sodium chloride or sodium carbonate solutions, plain water, or no water. The birds were chilled after treatment. Free chlorine concentrations were all below 20 ppm, pH was 7 units or more, and redox potentials were below 830 mV. None of the treatments produced more than a 0.3-log reduction in Campylobacter numbers compared to counts on untreated carcasses. This study concludes that, at the low chlorine concentrations allowed in the EU, spraying with electrolysed water is not an effective method of reducing the number or prevalence of Campylobacter on chicken carcasses.
Carcasses along slaughter lines were exposed to normal slaughterhouse air or ultraclean air provi... more Carcasses along slaughter lines were exposed to normal slaughterhouse air or ultraclean air provided from a unit fitted with a HEPA filter. In cattle slaughterhouses, aerobic viable counts were measured by sponging the brisket at the end of the line to determine whether the slaughterhouse air had led to contamination of the carcasses. Furthermore, a replica cattle carcass with settle plates attached was exposed to similar conditions. The greatest contamination of the plates occurred at the hide puller (P < 0.01). The use of ultraclean air reduced the deposition of organisms onto settle plates (P < 0.01). The airborne route contributed to contamination in cattle slaughterhouses, but other vectors were more important. Further study of contamination of the brisket, at the time that it was first exposed, showed that knives transfer contamination from the hide. The use of ultraclean air at this position showed that the airborne route was a contributor to contamination (P < 0.1),...
A model has been produced for predicting the temperature of liquid foods during vacuum cooling. I... more A model has been produced for predicting the temperature of liquid foods during vacuum cooling. It includes a mathematical description of the ingress of ambient air into process equipment, which leads to reduced cooling rates and the potential for contamination of the foodstufj? The model considers the air flow as an adiabatic compressible flow through a nozzle. The model was tested on a full-scale processing vessel containing 500 litres of water or a fruit/sugar preparation used in the production of yoghurts. The temporal trends of total vessel pressure, liquid temperature and the mass of condensed vapour were predicted well. Throughout the period of cooling, the difference bemeen measured and predicted values of pressure did not exceed 19 kPa, the liquid temperature was predicted to within 7°C and the mass of condensed vapour wus predicted to within 5 kg.
International Conference on the Epidemiology and Control of Biological, Chemical and Physical Hazards in Pigs and Pork, 2007
In order to determine typical and atypical operations in the slaughtering and dressing of pigs fo... more In order to determine typical and atypical operations in the slaughtering and dressing of pigs for pork and bacon practices and operations were recorded at eight pig abattoirs. Data included physical parameters such as temperatures and durations. The results indicate that plants are reasonably similar if processing pigs mainly for pork, but those processing mainly for bacon had more aggressive singeing and polishing (black scraper) arrangements. The plants visited used either hot water (tank) or vertical (sprayed hot water) scalding systems prior to dehairing. This study was carried out to establish a microbiological and physical process baseline which would then enable effective existing practices to be identified, as well as identifying those existing, and also novel, practices which have the potential to be developed in order to reduce carcass contamination by Salmonella.
Clinical congestive heart failure (CHF) is a major risk factor for strokes. Patients with CHF com... more Clinical congestive heart failure (CHF) is a major risk factor for strokes. Patients with CHF commonly have atrial fibrillation or flutter (AF), which is frequently associated with, may be a marker for, and may be the mechanism of, ischemic strokes. To determine whether stroke patients with CHF have a high incidence of AF (that may be intermittent and not diagnosed), we reviewed all the 12 lead ECGs in a fourteen year institutional ECG data base and the clinical records and the available echocardiograms of 985 patients who had an ischemic stroke over a 3-year period. We found that 31.3% of the stroke patients had evidence of AF. Clinical congestive heart failure was present in 168 stroke patients; 61.9% of these stroke patients with CHF had evidence of AF. In the total stroke population, patients with other risk factors for stroke (hypertension, advanced age, diabetes, coronary artery disease) had an increased incidence of AF; but among stroke patients with CHF, only advanced age (≥75 years) in addition to CHF increased the incidence of AF. To determine whether only the CHF stroke pts with systolic dysfunction had a high incidence of AF, we compared the incidence of AF in the 41.5% of the CHF patients with a depressed ejection fraction with the AF incidence in the 58.5% of CHF stroke patients with a normal ejection fraction (≥50%). The incidence of AF was the same (63.4% vs. 60.2%, p = 0.741) whether the ejection fraction was depressed or normal. These findings suggest that AF is common in patients with CHF who have strokes whether the ejection fraction is normal or depressed. CHF patients who have strokes and who are in sinus rhythm should be meticulously investigated for intermittent AF, so anticoagulation can be administered to prevent a further stroke.
International Journal of Food Science & Technology, 2017
These studies examined the effects of incorporating bubbles of air in the water used for cleaning... more These studies examined the effects of incorporating bubbles of air in the water used for cleaning surfaces. Small (<50 lm) or large (millimetre) bubbles were used, and these could aid cleaning by a scrubbing action, energy release or free radical production. Small or large bubbles improved the removal of biofilm from steel surfaces by 1.0 log 10 or 1.6 log 10 , respectively. Biofilm removal from a polypropylene pipe wall was improved by 0.9 log 10 by incorporating bubbles into the cleaning water. Further trials showed increased removal of carbohydrate, fat and protein deposits from stainless steel by incorporating bubbles into the water. These results suggest that the use of air bubbles in water could provide small improvements in cleaning or potentially similar contamination removal using less water.
L'invention a trait a un chariot a air sterile, qui comprend un corps mobile possedant au moi... more L'invention a trait a un chariot a air sterile, qui comprend un corps mobile possedant au moins un orifice d'admission d'air dans sa region inferieure et une pluralite d'orifices de sortie d'air dans sa region superieure, et contenant des moyens roues permettant de faire entrer de l'air par ledit orifice d'admission, de le faire passer a travers des moyens de filtrage, et de le faire sortir par les orifices de sortie. La region superieure du corps constitue une surface de travail sensiblement horizontale, caracterisee en ce qu'elle possede une paroi frontiere verticale s'etendant sur son pourtour, de facon que la surface de travail et la paroi frontiere forment un plateau, la paroi frontiere etant creuse. L'air filtre est dirige dans la paroi frontiere et est diffuse a travers les orifices d'admission d'air contenus dans la paroi frontiere, depuis les cotes opposes.
L'objectif de cette etude etait de savoir quelle etait la relation entre le nombre de particu... more L'objectif de cette etude etait de savoir quelle etait la relation entre le nombre de particules aeroportees et le nombre de microorganismes presents dans l'atmosphere des ateliers refrigeres de production alimentaire. Dans quatre ateliers (assemblage de sandwichs, garniture de dessert, pâte et quiche), ont ete effectuees des mesures de concentrations de particules par compteur laser et de concentrations de microorganismes par plaques d'impact. La proportion de particules contenant un microorganismes variait de 1 sur 200 tout pres du personnel se lavant les mains a 1 sur 30 000 dans une usine hygienique en periode de faible activite. Hormis le premier cas ci-dessus, le rapport moyen etait de 1 sur 3 500, mais ce rapport est trop variable d'un cas a l'autre pour que l'on puisse estimer la contamination aeroportee a partir du nombre de particules.
The transfer of contamination through the airborne route is significant in the assembly area of h... more The transfer of contamination through the airborne route is significant in the assembly area of high-care food factories preparing products such as sandwiches, prepared salads and chilled meals. This paper describes equipment designs that have been proposed to restrict such contamination and maintain low air temperatures around the food whilst allowing higher factory temperatures. Designs based on uni-directional flows, open troughs, semi-closed and closed tunnels are described. The uni-directional flow systems have been applied successfully in the chilled food industry although they require higher air flows than the other systems. Troughs offer good maintenance of temperature and low airborne counts around the food. Tunnels are more expensive and there are concerns about clean-ability of the equipment and, with the closed tunnels based on glove-box technology, potential problems of operator comfort.
Many ready-to-eat foods are stored frozen in commercial stores and then defrosted before dispatch... more Many ready-to-eat foods are stored frozen in commercial stores and then defrosted before dispatch to the retail outlet. Large variations in defrost time can reduce product throughput and lead to variable product quality. We propose that defrost rooms be considered as several zones of different heat flux with only small variations in heat flux in each zone. A type of food is located in a particular zone according to the difficulty of defrosting it, and the types and quantities of other foods being defrosted at the same time.
Journal of Physics E: Scientific Instruments, 1981
ABSTRACT The authors describe how a quadratic function in scale reading and a linear function in ... more ABSTRACT The authors describe how a quadratic function in scale reading and a linear function in temperature, over the range 20-90 degrees , adequately represents the flowrate of water measured with a rotameter.
Disinfectants are commonly applied as fogs in the chilled food industry. Recent research has show... more Disinfectants are commonly applied as fogs in the chilled food industry. Recent research has shown that fogging is eective in reducing the number of organisms on upwardfacing surfaces but, in general, it is not eective on vertical or downward-facing surfaces. Fogging also reduces the number of viable airborne organisms, although the reason for this decrease in not understood. Numerical models of the dispersion of airborne particles have been used to simulate the fogging process. These models, with supporting experiments, showed that fogs should be most eective when the median diameter of the fog droplets lies between 10 and 20 mm. Droplets in this size range disperse well and settle within about 45 min. This gives good coverage and the fog clears from the air quickly enough not to pose major disruption to factory operations. #
This study investigated the effectiveness of spraying electrolysed water for reducing the numbers... more This study investigated the effectiveness of spraying electrolysed water for reducing the numbers of Campylobacter on chicken carcasses. Previous studies have used solutions with free chlorine concentrations above 25 ppm and low pH to treat inoculated carcasses. The four trials described here were carried out at process plants treating naturally contaminated, hot, birds with electrolysed sodium chloride or sodium carbonate solutions, plain water, or no water. The birds were chilled after treatment. Free chlorine concentrations were all below 20 ppm, pH was 7 units or more, and redox potentials were below 830 mV. None of the treatments produced more than a 0.3-log reduction in Campylobacter numbers compared to counts on untreated carcasses. This study concludes that, at the low chlorine concentrations allowed in the EU, spraying with electrolysed water is not an effective method of reducing the number or prevalence of Campylobacter on chicken carcasses.
Carcasses along slaughter lines were exposed to normal slaughterhouse air or ultraclean air provi... more Carcasses along slaughter lines were exposed to normal slaughterhouse air or ultraclean air provided from a unit fitted with a HEPA filter. In cattle slaughterhouses, aerobic viable counts were measured by sponging the brisket at the end of the line to determine whether the slaughterhouse air had led to contamination of the carcasses. Furthermore, a replica cattle carcass with settle plates attached was exposed to similar conditions. The greatest contamination of the plates occurred at the hide puller (P < 0.01). The use of ultraclean air reduced the deposition of organisms onto settle plates (P < 0.01). The airborne route contributed to contamination in cattle slaughterhouses, but other vectors were more important. Further study of contamination of the brisket, at the time that it was first exposed, showed that knives transfer contamination from the hide. The use of ultraclean air at this position showed that the airborne route was a contributor to contamination (P < 0.1),...
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Papers by Dean Burfoot