1-s2.0-S0140700714002989-main
Survey and analysis of internal temperatures of Lebanese domestic refrigerators
Hussein F.Hassan a ,*,Hani Dimassi b ,Rafal El Amin a
a
Department of Natural Sciences,Nutrition Program,School of Arts and Sciences,Lebanese American University,Beirut,Lebanon b
School of Pharmacy,Lebanese American University,Byblos,Lebanon
a r t i c l e i n f o
Article history:Received 10July 2014Received in revised form 29October 2014
Accepted 31October 2014
Available online 11November 2014Keywords:Refrigerator Temperature Data loggers Questionnaire Lebanon
a b s t r a c t
In the light of power crisis that Lebanon is witnessing,temperatures were recorded,using data loggers,in 147domestic refrigerators in three main cities every 5min over 3days.A questionnaire was administered to gather information on household characteristics,power supply and refrigerator.Temperatures were on average 8.0 C with minimum à5.9 C and maximum 37.0 C.Income,number of household members,age,brand,load level and seal of the fridge,frequency of power cuts and availability of alternative power had no signi?cant effect on the overall mean temperature,while the city and the distance to heat source had a signi?cant effect.The number of high temperature readings (T >6 C)differed signi?cantly between the cities,while the availability of an alternative power was borderline signi?cant.The lowest average temperatures were recorded during the night and 70%of average temperatures were in the danger zone (above 6 C).This study can provide input to food safety risk assessments.
?2014Elsevier Ltd and IIR.All rights reserved.
Etude et analyse des temp e
ratures internes de r e frig e rateurs domestiques libanais
Mots cl e s :R e
frig e rateur ;Temp e rature ;Enregistreurs de donn e es ;Questionnaire ;Liban 1.Introduction
The reported incidence of gastrointestinal illness in Lebanon
is increasing with a signi?cant proportion of cases thought to be foodborne (Dib,2009).In order to minimize microbiological growth on food and prevent foodborne diseases,temperature control throughout production,transportation,storage,retail
display and domestic refrigeration is vital and information relating to temperature pro?les during these stages is crucial to assess and manage pathogen-associated risks.For instance,the most commonly recommended temperature range for food refrigeration is 1e 5 C (Gilbert et al.,2007).
Foodborne illness is initiated in private homes three times more frequently than in commercial facilities (Sheard,1986;Borneff et al.,1988;Scott,1996;Scuderi et al.,1996).In
*Corresponding author .Tel.:t9611786456x1609,t9613191445;fax:t9611867098.E-mail address:hussein.hassan@https://www.sodocs.net/doc/f914479869.html,.lb (H.F.
Hassan).w w w.ii ?i r.o r g
Available online at https://www.sodocs.net/doc/f914479869.html,
ScienceDirect
journal homepage:
https://www.sodocs.net/doc/f914479869.html,/locate/ijrefrig
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https://www.sodocs.net/doc/f914479869.html,/10.1016/j.ijrefrig.2014.10.026
0140-7007/?2014Elsevier Ltd and IIR.All rights reserved.
addition,up to 50%of these foodborne illness cases were linked to inappropriate food storage including ineffective chill storage and refrigerator management.Refrigerators form an important link in the wider chain of cross-contamination,and a signi?cant factor of outbreaks of domestic foodborne dis-ease (Ryan et al.,1996).However,the increasing importance of chilled,“ready-to-eat ”products,which now make up to 60%of the average European shopping basket (Anonymous,2003a,2003b,2003c ),means that the refrigeration practices will continue to be major determinants in domestic food safety (Ryan et al.,1996).According to a recent report published by the Institution of Mechanical Engineers,25%of food wastage in the developing world could be eliminated with better refrigeration (Eagle,2014).
Despite the good hygiene and equipment advances,do-mestic refrigeration,which is not covered by laws and regu-lations in majority of countries,is still a source of concern (Laguerre et al.,2002).Lebanon is currently facing the worst electrical power supply in its history.An estimate of 90%people spend long hours in darkness (Al Amin,2012)which is most likely affecting the internal temperature of domestic fridges and thus;putting the Lebanese population at high risk of foodborne illnesses.
Few studies have been carried out worldwide to study the refrigeration temperature in domestic settings.In China,only 2.3%of domestic refrigerators operate with a temperature <6 C,34.1%within 8e 12 C,34.1%within 12e 14 C and 29.5%operate at >14 C (Shixiong and Jing,1990).In France,the mean temperature of >70%of refrigerators is over 6 C and a majority of surveyed participants were unable to state the temperature at which they attempted to operate their refrigerator (Victoria,1993).Furthermore,15%of surveyed households in United Kingdom and 0%in Northern Ireland and New Zealand used a thermometer to control the refrig-erator temperature.In addition,the refrigerator temperature was found to be in?uenced by a combination of factors (Flynn et al.,1992;James and Evans,1992).In New Zealand,the ma-jority of appliances were not operating within the recom-mended temperature range and a high percentage of responders were unaware of the safety zone,and did not have the means to check internal temperatures as none of the refrigerators were ?tted with thermometers (O 'Brien,1997).Also,33%of the temperature measurements in refrigerators in this country exceeded 5 C (Anon.,2007).In addition,overall mean temperature was 5.2 C and a signi?cant proportion (34%)had a mean temperature >6 C,while 55%had a mean temperature of >5 C (Gilbert et al.,2007).In Sweden,5e 20%of the food items were stored at temperatures above 10 C (Marklinder et al.,2004).In a Malaysian study done by Rahman et al.(2005),the temperatures of the surveyed refrigerators were:minimum à2.8 C,average 2.0 C,and maximum 7.5 C.In USA,20%of domestic refrigerators were found to operate at >10 C (Jol et al.,2005).
No study was carried out previously in Lebanon to study the refrigerator temperature on the domestic level and to analyze the factors affecting it.The present study was done to (1)monitor the air temperature inside the refrigerator under real-use conditions and (2)to analyze the factors which have the greatest impact on refrigerator temperature.Results of our study would provide input for quantitative risk analysis models and act as a useful tool for promoting food safety.
2.Materials and methods
One hundred forty seven (147)representative refrigerators were surveyed between November 2013and December 2013from the three major Lebanese cities (Beirut:n ?74;Tripoli:n ?37and Saida:n ?36).All refrigerators were fridge-freezer type.Selected sample size per city was calculated in a proportional way according to each city 's population as per the Central Administration of Statistics in Lebanon;that is why,Beirut had the highest number of participating house-holds,followed by Tripoli and Saida.Trained investigators interviewed a family representative and ?lled in a question-naire to obtain information on the characteristics of the family (area of residence,income,gender and age of the family members),the characteristics of the power supply (frequency of power cuts,availability and frequency of the alternative power),and the characteristics of the fridge (age,seal status,brand name,volume,load level,distance to heat source and presence of a thermometer).An explanation of the study objectives,signi?cance,and protocol,and request for the household representative to participate in the study were included on the ?rst page of the questionnaire.Upon initial approval,informed written consent was obtained from each participant who was willing to participate in the study.The study protocol was approved by the Institutional Review Board at the Lebanese American University.A pilot study (12households)was done to get a preliminary validation of the questionnaire.The clarity and suitability of wording,in addi-tion to the average time needed for its completion were assessed.Then,necessary modi?cations were made and the results of the preliminary study were not included in the data analysis.
Data loggers (EBI 20,Ebro,Ingolstadt,Germany)with single sensors were programmed to record the temperature every 5min over a period of 3days.They were mounted at the middle shelf of the refrigerator near the corner furthest from the door hinges.After recovery of data loggers,temperature recordings were extracted and analyzed.
SPSS v18Statistical computer software was used for all statistical analyses.The characteristics of the family,power supply and fridge were the independent variables.Overall mean temperature of the fridge for the three days,average of temperature recordings per day,average of temperature recordings per time slot (12:00AM e 6:00AM;6:00AM e 12:00PM;12:00PM e 6:00PM and 6:00PM e 12:00AM)and number of high temperature readings (tempera-ture >6 C)represented the dependent variables.Analysis of Variance (ANOVA)was conducted to assess the effect of each independent variable and signi?cance level of 0.05was
used.
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166
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3.Results and discussion
3.1.Characteristics of the household,power supply and
refrigerator
Household,power supply and refrigerator characteristics are
shown in Table1.It can be observed that the majority of
households(57%)have5members.Majority of participants
(75%)had an income below$1500monthà1.35%of households
had governmental power cuts exceeding6h dayà1and65%of
them had an alternative power supply.The governmental
power was stable in91%of cases,while the alternative power
was stable in78%of the cases only.Fifteen percent of the
surveyed fridges were unplugged when the power was on.63%
of the fridges had an age of over7years and41%of them had a
perfect door seal.Door seal quality was determined visually
based on three different door seal models that we used as a
reference.Perfect seal was the one with no defects;medium
was the one with1e2defects;bad was the one having>2
defects.
No speci?c brand name was prevalent and43%of the
fridges were less than a meter close to a heat source(oven,
dishwasher and washing machine).18%of the fridges were
less than1/3full,while100%of participants did not have a
thermometer to check the internal temperature of the fridges.
3.2.Refrigerator overall average temperature
Fig.1shows the distribution of the mean internal temperature
of the147surveyed refrigerators.Overall mean temperature
was8.0±3.5 C and71%of the fridges had an individual
average temperature in the danger zone above6 C.Temper-
ature recordings ranged betweenà5.9and37 C.
Effect of different variables on the overall average tem-
perature of refrigerators is presented in Table2.
Highest overall average temperature by city was recorded
in Beirut(8.8 C),followed by Saida(8.2 C)and Tripoli(6.4 C)
and the difference was signi?cant(p<0.05).This can be
Fig.1e Distribution of the individual average temperature
of the147surveyed refrigerators.
attributed to the fact that Beirut,being the country capital,gets longer governmental power feeding compared to other cities;that is why its residents tend not to get alternative power to save money.This was not the case in Saida and Tripoli where surveyed participants reported that,in most of the cases (68%),an alternative power is available.On the other hand,as the number of family members increased,the fridge temperature increased from 8.2 C (1e 3members)to 9.6 C (!6members)probably due to the fact that as family size increased,the tendency of opening the fridge was higher,resulting in reducing the cooling ef?ciency,and the difference was borderline signi?cant (p ?0.09).Whenever both the governmental and alternative power sources were not avail-able,fridge average temperature was 9.1 C compared to 8.0 C in the case of the continuous presence of a power source;however,the difference was not signi?cant (p >0.05).As long as the age of the fridge was below 19years,average temper-ature was 8 C vs.10 C for above 19years old fridges and the difference was borderline signi?cant (p ?0.1).As the level of fridge loading density increased,the average temperature increased from 8.2 C for less than 1/3full to 8.9 C for packed
full fridges;however,the difference was not signi?cant (p >0.05).This can be due to the lower effectiveness of the cold air circulation inside the fridge whenever it is full.On the other hand,when the fridge seal was in perfect condition,the average temperature was lower (7.9 C)than when the seal was in bad condition (10.0 C);however,the difference was not signi?cant (p >0.05).Regarding the distance to heat source,whenever the fridge was less than a meter close to the oven,dishwasher or washing machine,the average temperature was signi?cantly (p <0.05)higher.This can be aggravated whenever the seal condition is bad.In this case,heat gener-ated from such equipment will ?nd an easier route to enter the fridge and increase its temperature.
3.3.
Refrigerator high temperature readings
A reading of the fridge above 6 C was considered as high (Shixiong and Jing,1990).Table 3shows the effect of different variables on the percent of high temperature readings.
High temperature readings were found mostly (80%)in Beirut,followed by Saida (69%)and Tripoli (54%)and the dif-ference was signi?cant (p <0.05).Since Beirut is the capital of the country,the cuts in the governmental power supply are the least frequent among the Lebanese cities;therefore,the residents of Beirut avoid subscribing in an alternative power source to save money,unlike in the other two cities,where the cuts are very frequent and getting an alternative power is a must.As the number of family members increased and in cases where no power was supplied to the fridges,the %of
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168
high temperature readings increased,yet not signi?cantly (p>0.05).A similar observation was recorded when the fridge was older,larger or packed full.In addition,when the seal was bad and when the fridge was close to a heat source,~77%of the readings were in the danger zone(above6 C).Such?nd-ings complement the ones reported in Table2.On the other hand,whenever there was not an alternative power,%high temperature readings was higher,yet the signi?cance was borderline(p?0.07).
Table4shows the minimum,maximum and mean tem-peratures recorded in different studies(James et al.,2008).
In our study,71%of the mean temperatures exceeded6 C, which is comparable to the results(>70%)reported by the United Kingdom(Evans et al.,1991),North Ireland(Flynn et al., 1992),France(Victoria,1993),USA(Daniels,1998),Netherlands (Terpstra et al.,2005)studies.All of these countries are developed and do not face any power feeding issues,yet their mean temperature values were comparable to ours.This can lead to the conclusion that the power supply characteristics do not have a major effect on the refrigerator mean temperature.
3.4.Average temperature difference according to the day and time slot
Changes in the average internal temperature of the re-frigerators according to the day and time slot are shown in Fig.2.
Average temperature difference between day1,2and3was not signi?cant(p>0.05).This can be attributed to the fact the power supply feeding,whether from governmental or alter-native sources,is stable.On the other hand,slot2 (6:00AM e12:00PM)and slot3(12:00PM e6:00PM)recorded the highest average temperature(~8.5 C)compared to slot1 (12:00AM e6:00AM)and slot4(6:00PM e12:00AM)and the difference was signi?cant(p<0.05).This can be attributed to the fact that housewives and other family members tend to open the fridge to get food mostly between6:00AM and
Fig.2e Average temperature changes by day and time slot.
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6:00PM.The higher frequency of fridge door opening during this time range resulted in less cooling ef?ciency and thus, higher recorded temperatures.
A composite score of four characteristics of the refrigerator (age,seal condition,level of fridge?lling and distance to heat source)was created.Score ranged between1and4,where the fridge gets a score of4whenever the age is below19,seal condition is perfect,fridge is fairly full and distance to heat source is more than two meters.As the score was lower,the overall average temperature of the fridge increased signi?-cantly(p<0.05).
4.Concluding remarks
Microorganisms can multiply very quickly if food is not stored appropriately.The high domestic refrigerator tem-perature reported in our study implicates that the Lebanese population is consuming risky foods and thus,it can be at higher susceptibility to food poisoning.Our study high-lighted that under certain conditions,refrigerator tempera-tures can increase and then take several hours to return to the correct operating temperature.Having a new enough refrigerator with a good door seal,in addition to keeping it far from heat sources,had a major impact on the refrigerator https://www.sodocs.net/doc/f914479869.html,rmation campaigns,explanatory bro-chures and posters,in addition to providing thermometers are helpful tools to educate consumers on ef?cient use of their refrigerators.
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