The Microbial and Chemical Quality of Ready-To-Eat Olivier Salad in Mashhad, Iran Mahdi Ram1, Milad Tavassoli2, Golnaz Ranjbar2, Asma Afshari2* 1
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JOURNAL OF NUTRITION FASTING AND HEALTH The Microbial and Chemical Quality of Ready-to-Eat Olivier Salad in Mashhad, Iran Mahdi Ram1, Milad Tavassoli2, Golnaz Ranjbar2, Asma Afshari2* 1. Department of Food Hygiene and Aquatics, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran. 2. Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. A R T I C L E I N F O A B S T R A C T Article type: Introduction: Olivier salad is a commonly used cold fast food in Iran, which contains various Research Paper nutrients. However, this food product is susceptible to bacterial contamination. The present study aimed to evaluate the chemical and microbial quality of the ready-to-eat Olivier salads sold in the Article History: groceries in Mashhad, Iran. Received: 26 May 2019 Methods: This study was conducted on 26 samples of two types of Olivier salad containing Accepted: 14 Aug 2019 chicken (n=17) and meat (n=9), which were collected from the local markets in Mashhad city. The Published: 25 Nov 2019 samples were transferred to the laboratory in cold flasks to evaluate their microbial quality (coliforms, Escherichia coli, Staphylococcus aureus, Salmonella spp., clostridium perfringens, molds, and yeasts) and chemical quality (potassium sorbate, potassium benzoate, and benzoate levels) Keywords: based on the Iran national standard No. 17813 and 17813-a-1, respectively. Olivier Salad Results: Chemical tests indicated no significant differences in the levels of potassium sorbate, Microbial contamination potassium benzoate, and benzoate (P>0.05) between the samples. On the other hand, 7.7% (2/26) Salmonella and 23.07% (6/26) of the Olivier salad samples were contaminated with Salmonella and Staphylococcus aureus Escherichia coli, respectively, while all the samples were negative for Staphylococcus aureus Preservatives contamination. Conclusion: Salmonella and Staphylococcus aureus are of particular importance in food contamination. Lack of hygiene during production, contamination of raw materials, and elevated storage temperature are among the key influential factors in the increased contamination of food products. Therefore, the control and monitoring of the food chain must be prioritized. Please cite this paper as: Ram M, Tavassoli M, Ranjbar G, Afshari A. The Microbial and Chemical Quality of Ready-to-Eat Olivier Salad in Mashhad, Iran. J Nutrition Fasting Health. 2019; 7(4): 175-181. DOI: 10.22038/jnfh.2019.40572.1199 Introduction process of RTE sandwiches, salads, and meats Use of ready-to-eat foods has been on the rise involves manual interference (e.g., cutting or due to lifestyle changes, increased urbanization, crushing), which could lead to the and the advantages of such foods as they are contamination of the products (4, 5). easy to use and could be prepared within a short Cold chain is considered to be the only method time. Iran is a developing country where the to control the quality of RTE Olivier salads after consumption of these food products is highly production (6). However, various pathogenic common, especially Olivier salad (1). psychrotrophic bacteria could grow at Available data indicate that 60% of Europeans refrigerated temperatures, such as Yersinia use ready-to-eat (RTE) foods (1, 2). Cold food enterocolitica, Clostridium botulinum type E, refers to the food products with the shelf life of Listeria monocytogenes, and Aeromonas more than five days at refrigerated hydrophila (7, 8) temperatures (3). Since these products are at In appropriate conditions, microorganisms the risk of corruption, the manufacturers often could grow in RTE Olivier salad (9). use preservatives at higher levels than the Staphylococcus aureus is a normal flora of the national standards in order to prevent their skin and upper respiratory tract in humans, corruption due to the inappropriate transport which could be transmitted to food during the and maintenance of the products at improper preparation chain (9-12). Vegetables are temperature (1, 3). Due to the variety of their another key ingredient in Olivier salad, which composition, RTE products constitute a major could become a source of Salmonella and part of the human needs for carbohydrates, Escherichia coli transmission (13). Clostridium protein, and fat in meals. The preparation perfringens is another bacterium causing food * Corresponding author: Asma Afshari, Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. Tel: +985138002382, Email: [email protected]. © 2019 mums.ac.ir All rights reserved. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Ram M et al J N FH Microbial and Chemical Quality of A Ready-to-Eat Food poisoning, which is considered to be a spoilage dilution was streaked on the PCA plates and factor in industrial food products. Furthermore, incubated at the temperature of 30°C. the bacterium causes necrotic enteritis (NE), Enumeration of Coliforms which is a rare, severe human infection (14, 15). A colony count technique based on the Iran Coliforms are the bacteria that are frequently national standard No. 11166 was performed for transmitted to salads through contaminated the enumeration of the coliform bacteria. After water with human feces or due to the lack of the preparation of the serial dilutions, 0.1 hygiene in the processing environment of milliliter of each dilution was transferred to the Olivier salad (16, 17). In addition, fungal spores plates containing violet red bile agar (Merck, are extremely common in the air and could be Darmstadt, Germany) and incubated at the transferred to various salads, thereby causing temperature of 30°C or 37°C for 48 or 24 hours. food spoilage and diseases in humans. The presence of molds could also be attributed to Enumeration of Staphylococcus aureus improper packaging conditions (18, 19). At this stage, 25 grams of each sample was Sodium benzoate and potassium sorbate are weighed and homogenized with 225 milliliters widely used as preservatives for the prevention of buffered peptone water (BPW) (Merck, of microbial growth and increase the shelf life Darmstadt, Germany) for approximately five and quality of food products. However, these minutes. The obtained samples were further compounds have permissible limits and should diluted with BPW, and 0.1 milliliter of each not be used at higher concentrations (20, 21). dilution was spread on the surface of the Baird- Benzoate exposure is inevitable for most Parker media (Merck, Darmstadt, Germany) individuals as this compound is produced by gut (12). microbes (Beyoğlu and Idle, 2012) and is also Enumeration of Escherichia coli found in many berries and milk products A specific amount of the test samples was (<40 mg/kg) (Rangan and Barceloux, 2009a). inoculated into lauryl sulfate enrichment broth Moreover, reports suggest that exposure to (Merck, Darmstadt, Germany). Afterwards, the sodium benzoate through food could cause inoculated medium was incubated at the asthma (Petrus et al., 1996) or allergic reactions temperature of 37°C for 24-48 hours for gas in children (Jacob et al., 2016). production. After observing the turbidity or gas The present study aimed to evaluate the in the tube, it was inoculated into a tube microbial safety and chemical properties of RTE containing the Escherichia coli broth (Merck, Olivier salad in Mashhad, Iran as a commonly Darmstadt, Germany). Following that, the E. coli consumed RTE product. tube was inoculated at the temperature of 44°C Materials and Methods for 48 hours and examined for gas production after 24 hours. Differentiation of E. coli was Sampling carried out using indole, methyl red, Voges- In this study, Olivier salad samples were Proskauer, and citrate utilization test (21). aseptically collected from the markets of Mashhad city during the spring of 2019. In total, Isolation of Salmonella spp. 26 samples were collected, including two types At this stage, 25 grams of each sample was of Olivier salad containing chicken (n=17) and weighed and homogenized with 225 milliliters meat (n=9). All the samples were produced of BPW and incubated at the temperature of under the supervision of the Iranian Ministry of 37 ͦC for 24 hours. For pre-enrichment, 0.1 Health. milliliter of the sample was transferred to the Rappaport-Vassiliadis enrichment broth (Merck, Microbial Analysis Darmstadt, Germany) and incubated at the Total Count temperature of 42 ͦC for 24 hours. For According to the Iran national standard No. enrichment in the selected liquid medium, one 5272, colony count was performed at the milliliter of the obtained sample was transferred temperature of 30°C using the plate count agar to the selenite cystine broth (Sigma-Aldrich, (PCA; Merck, Darmstadt, Germany). After the USA) and incubated at the temperature of 37 ͦC preparation of a suspension, a serially tenfold for 24 hours. Finally, one loop was streaked dilution was obtained, and 0.1 milliliter of each onto the Hektoen enteric agar and Brilliant Green agar (Merck, Darmstadt, Germany) and 176 J Nutrition Fasting Health. 2019; 7(4): 175-181. Microbial and Chemical Quality of A Ready-to-Eat Food J N FH Ram M et al incubated at the temperature of 37 ͦC for 24-48 using high-performance liquid chromatography hours. (HPLC) and through separation using ACE-121- In order to confirm the isolates, one colony was 1504 C18 HPLC column (15 cm x 3.9 mm I.D., 5 inoculated in tubes containing Triple Sugar Iron µm). The acetate buffer was prepared with 0.30 agar (Sigma-Aldrich, USA) (22). gram of ammonium acetate in 900 milliliters of HPLC grade water and glacial acetic acid in Enumeration of Clostridium perfringens order to adjust the pH at 4.20. Afterwards, the At this stage, 10 grams of each sample was ammonium acetate buffer solution was filtered homogenated with 90 milliliters of BPW, and through a Millipore Millex-HV filter (0.45 µm; one milliliter was added to a tube containing Hydrophilic Vinylidene).