Introduction: Food contamination with microorganisms can occur at any stage of the process, from food production to consumption, and can be the result of environmental contamination. This study was carried out in order to identify the microorganisms forming the flora and to determine the level of microbial contamination of the internal surfaces of devices in the cold chain of butcher shops. Method: This is a comparative cross-sectional descriptive study of 30 internal surfaces of ten devices in the chain of two butchers. Results: It seems that the sampling points of Butchery 1 have the highest level of contamination at 87% compared to Butchery 2 (46.67%) with a p = 0.02508 (<0.05). the organisms isolated were S. aureus (54%) and albus (23%), fusarium and A. niger respectively with 8%, and A. fumagitus (7%); against 47% (Boucherie II) with a, The isolated microorganisms were S. aureus (43%), 29% for K. planticola and 14% for A. fumagitus and fusarium spp. The level of surface contamination for all isolated organisms was >1000 CFU/cm2. The operating temperature range of the devices varied between -2°C and 6°C, with an average of -3.2°C in Butchery 1 versus -4.6°C and 6°C, with an average of -4°C, 7°C for the Butcher 2. Conclusion: Food pathogens and opportunists can survive on the surfaces of cold chain equipment in butcher shops and therefore pose a risk of cross- contamination.
Cross-contamination of food with pathogens in the retail environment is a significant public health problem that contributes to an increased risk of foodborne illness [
The internal faces of cold chain devices can be contaminated by pathogenic microorganisms of food origin [
Existing global food safety standards help improve and standardize manufacturing practices, good hygienic practices, risk analysis, critical control point, for safer processed foods [
Hence the interest to deepen the knowledge on the current state of butchers, includes bacteriological analysis of food samples and environmental risk assessment and training of staff, in order to improve the quality microbiological of internal surfaces of cold chain devices. We therefore sought to identify the microorganisms forming the flora and to determine the level of microbial contamination of the internal surfaces of devices in the cold chain of butcher shops.
We carried out a comparative cross-sectional descriptive study in two butchers in the city of Lubumbashi. Haut-Katanga province in the Democratic Republic of Congo (DRC) is over a period from June 29 to July 11, 2020, i.e. two weeks. Thirty (30) samples were taken from the internal surfaces of 10 devices in the cold chain of butcher shops accessible with the consent of the promoter. The sample was taken under aseptic conditions. Samples were taken from the bottom and from two surfaces using the dry sterile swabs and sent to the laboratory for analysis within one hour of collection. Different culture media were prepared according to the recommendations of the manufacturers. To obtain the isolated bacteria the samples were inoculated on CLED Agar, mannitol salt agar and Mac Conkey Agar. Microbiological analysis: To obtain the fungal isolates, the samples were inoculated on Sabouraud Dextrose Agar (SDA). The initial identification of the isolated bacteria was based on their cultural and morphological characteristics. Further identification was by biochemical characteristics using standard procedures. GRAM coloring: A thin smear from a 24-hour culture was made on a fat-free, heat-fixed slide by passing the slide quickly over a Bunsen burner flame after air drying. The prepared smear was then flooded with crystal violet solution for about one minute, rinse with tap water; followed by mordanting with Lugol (iodine-iodine solution): spread the Lugol and leave to act for 1 minute, rinse with tap water; after d colorless with alcohol (+acetone): pour the alcohol or an alcohol-acetone mixture drop by drop onto the slanted slide, and monitor the discoloration (30 seconds). Rinse with tap water; the smear was counterstained with Safranin for 1 minute, washed with tap water; Air dry the slide; Observe with a drop of objective 100 (×1000) immersion oil. Color purple signifies a gram positive organism while pink to red signifies gram negative. Catalase test: Place on a glass slide one or two drops of hydrogen peroxide at 10 volumes. Using the taper of a Pasteur pipette, take a fragment of a colony and dissociate the culture in hydrogen peroxide. The release of bubbles immediately indicated a positive test while it was negative when no bubbles were formed.
Interpretations
Statistical analysis: The microbiological results obtained after incubation were entered using MS Excel 2016 software; processed and analyzed with Excel 2016 and Epi info software version 7.2.2.6. For the analysis and interpretation of the data, the following calculations and statistical tests were used: frequency, mean and standard deviation, the Fischer Exact test and the Mann-Whitney/Wilcoxon test.
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Structure | Contamination of surfaces | |||
---|---|---|---|---|
No | Yes | |||
Frequency | Percentage (%) | Frequency | Percentage (%) | |
Butcher I | 2 | 20 | 13 | 87 |
Butcher II | 8 | 53 | 7 | 47 |
*p = 0.02508.
Isolated microorganisms | Butcher I | Butcher II | ||
---|---|---|---|---|
Frequency | Percentage (%) | Frequency | Percentage (%) | |
Bacteria | 10 | 77 | 5 | 71 |
Molds | 3 | 23 | 2 | 29 |
Isolated microorganisms | Percentage (%) | ||
---|---|---|---|
Butcher I | Butcher II | ||
Staphylococcus | |||
Staphylococcus aureus | 54 | 43 | |
Staphylococcus albus | 23 | 0 | |
Klebsiella planticolla | 0 | 29 | |
Molds | |||
Aspergillus fumagitus | 7 | 14 | |
Aspergillus niger | 8 | 0 | |
Fusarium spp. | 8 | 14 | |
Flora | Average ± Etype | ||
---|---|---|---|
Butcher I | Butcher II | ||
Staphylococcus | 3.47 ± 0.5 | 0.80 ± 2.21 | |
Klebsiella planticolla | - | 0.51 ± 1.57 | |
Fusarium spp. | 0.27 ± 1.04 | 0.26 ± 0.97 | |
Aspergillus | 0.53 ± 1.68 | 0.27 ± 1.04 | |
*p = 0.7490.
depending on whether it was butchery 1 st 2 (in log10 CFU/cm2): S. aureus and albus 3.47 and 0.80, aspergillus fumagitus and niger 0.53 and 0.27 for fumagitus; fusarium 0.27 and 0.26. Klebsiella planticola 0.51. The difference between the averages of microbial contamination of the internal surfaces of devices in the cold chain of butcheries is not significant. With a p = 0.7490 (>0.05).
The temperature of the devices of the observed Butcher I ranged from −2˚C to 6˚C, with an average temperature of −3.2˚C. The temperature ranges of the cold chain devices observed (Butcher 2) varied between −4.6˚C and 6˚C, with an average temperature of −4.7˚C.
The answers of the people questioned reveal that the cleaning of the internal surfaces of the cold chain devices is carried out every morning before the start of activities and the opening for the sale of food in the two butcheries, and at the end of each. Day to restore the surfaces to a clean state in the butcher’s shop I; The sponge (cloths), squeegee and buckets are the cleaning tools most often used in both structures. The cleaning/disinfection products used contained acetic acid and bleach as active ingredients.
The sampling points of Butchery 1 have the highest level of contamination at 87% compared to Butchery 2 which has a frequency of 46.67% of contaminated areas. There is a significant difference between the contamination of the internal surfaces of the cold chain devices between butchery I and II 0.02508 (<0.05). Otu-Bassey et al., 2017 found that 100% of refrigerators inspected show bacterial contamination, 32% fungal contamination and 8% contamination by parasitic organisms.
According to the indications of the service note DGAL/SDSSA/N2007-8275 France on the microbiological criteria applicable to carcasses of slaughter animals and poultry, and of the guidelines relating to the surface controls of the material in slaughterhouses and in cutting plants slaughter animals and poultry. Our results are unsatisfactory because they are greater 1000 CFU/cm2 or 1 Log10 CFU/cm2 on all surfaces sampled [
At the butcher I, S. aureus account for 54% of enumerated bacteria, followed by S. albus (23%) of A. Niger and Fusarium spp (8%), A. fumagitus (7%); on the other hand, at the level of butchery II, S. aureus represent 43% of the counted flora, K. planticola (29%) and respectively 14% for asp. fumagitus and fusarium spp. Macias-Rodriguez et al., In 2013; Kampmann et al., In 2008; Otu-Bassey et al., In 2017 reported that the bacterial genera isolated in decreasing order of frequency were: Staphylococcus aureus 27.3%, Escherichia coli 20.2%, Shigella spp 13.0%, Pseudomonas aeruginosa 11.9%, Aeromonas hydrophilia 8.3%, Salmonella typhi 5.9%, Klebsiella pneumonia 5%, Streptococcus pyogenes 4.7% and Proteus mirabilis 2.3%. The fungal organisms isolated were C andida albicans 54%, penicillium spp 43.2% and a spergilus flavus 2.7% while the parasites detected were Entamoeba histolytica/dispar 50% and Ascaris lumbricoides 50% [
The averages of the count of microorganisms detected on the internal surfaces of the cold chain devices are presented as follows depending on whether it was butchery 1 st 2 (in log10 CFU/cm2): Staphylococcus aureus and albus 3, 47 and 0.80, aspergillus fumagitus and niger 0.53 and 0.27 for fumagitus; fusarium 0.27 and 0.26. Klebsiella planticola 0.51. The difference between the averages of microbial contamination of the internal surfaces of devices in the cold chain of butcheries is not significant. With a p = 0.7490 (>0.05). Otu-Bassey et al., In 2017; Oluwafemi et al., in 2015. Have isolated other species of bacteria and fungi in home refrigerators, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Enterobacter spp., Klebsiella spp. and Shigella spp., Aspergillus flavus, A. niger, A. fumigatus, Saccharomyces cerevisae and Rhizopus spp. [
These unwanted organisms may have entered cold chain devices from unwashed raw foods, poorly packaged foods (meats, eggs, and milk), dirty hands, through an open refrigerator door, fluctuating temperatures, and surfaces of unsuitable containers placed in the refrigerator.
Temperature is one of the main factors in controlling food quality and safety due to its influence on microbial growth rates. Despite the fact that the low temperature can reduce the growth rate of many species of microorganisms, it has been reported that psychrotrophic microorganisms can thrive under normal refrigeration temperatures [
The WHO [
To eliminate a maximum of microorganisms, it is advisable to carry out a cleaning with a detergent, in order to eliminate the major part of the soils present on the surfaces, then to disinfect.
The antimicrobial properties of acetic acid are attributed to their acetic acid and citric acid content, respectively [
The responses on the frequency of cleaning/disinfection obtained in our survey are similar to those obtained in the INCA survey carried out by [
The sponge (cloths), squeegee and buckets are the cleaning tools most often used in both structures. Using the same sponge to clean both cold chain devices and other surfaces promotes the circulation of microorganisms in the structure. In addition, a frequently used and thus almost always wet sponge is therefore very loaded with microorganisms [
Food pathogens and opportunists can survive on the surfaces of cold chain equipment in butcher shops and therefore pose a risk of cross-contamination. Through our results, we have established that butcher’s cold chain devices for food storage are not as sterile. Enterobacteriaceae as well as molds constitute the resident flora of the internal surfaces of the devices of the cold chain in our environment, hence the importance of the control of the operating temperature, regular effective cleaning/disinfection regimes which must be communicated butcher shops in order to ensure the quality and safety of the surfaces made available to the production function and the sale of foodstuffs.
Thanks to the School of Public Health of the University of Lubumbashi and to all the authors of this article who made a significant contribution in the design, implementation and/or analysis and interpretation of the data, elaboration of the article and critical review of its content
The authors declare no conflicts of interest.
Diyoka, C.K., Omba, I.K., Lambo, G.N., Ilunga, E.K., Mposhy, P.E.M. and Mjumbe, C.K. (2021) Microbiological Control of Internal Surfaces of Appliances in the Butcher’s Cold Chain in Lubumbashi. Open Access Library Journal, 8: e7731. https://doi.org/10.4236/oalib.1107731