Dept. of Food Hygiene,

Fac. of Vet. Med. Assiut Univ.

Fecal contamination of ice cream mix powder sold in Assiut City

(With 4 Tables)

By

Enas El-Prince Mohamed;

Amal Ali Abdel-Haleem*; A.A. ABdEL-HAMEID

 and Manal Mohamed Amin Abdel-Rahim*

* Animal Health Institute, Assiut, Egypt

(Received at 16/12/2006)

التلوث القولونى البرازى لبودرة مخلوط الآيس کريم المباع فى مدينة أسيوط

إيناس البرنس محمد , آمال على عبد الحليم , أحمد عبد الحميد أحمد, منال محمد أمين عبد الرحيم

بالرغم من أن الآيس کريم يعتبر من منتجات الألبان الواسعة الانتشار، السهلة الهضم، ذات القيمة الغذائية العالية، والذى ينتشر تداوله بين فئات کثيرة وأعمار مختلفة من المستهلکين, إلا أنه قد يتعرض, تحت ظروف الإنتاج المختلفة وکذلک التصنيع والتوزيع، للتلوث الميکروبي بمختلف الأنواع الممرضة والتى تشکل خطورة لا يستهان بها على صحة المستهلک، ومنها الميکروبات القولونية البرازية, لذلک کانت هذه الدراسة على بودرة مخلوط الآيس کريم المباع فى مدينة أسيوط. وقد تم جمع عدد 150 عينة عشوائية منها مختلفة الطعم مثل الشيکولاتة والمانجو والفراولة والفانيليا والبرتقال والموز وکذلک النيسکافيه (کل عبوة 200 جم) وذلک من محلات مختلفة بمدينة أسيوط بتاريخ صلاحية عامان من تاريخ الإنتاج وقد تم فحص هذه العينات للوقوف على مدى تلوثها بالميکروبات القولونية البرازية. وقد أسفرت النتائج على أن الميکروبات المعوية قد تم عزلها بنسبة 38.7% من عينات بودرة الآيس کريم وکانت تحتوى على أعداد تراوحت بين ²10و 8.7ײ10 بمتوسط عددى قدره 3.2×10 لکل جرام وکانت معظم العينات (79.32%) تحتوى على أعداد أقل من ²10 وأخرى بنسبة 20.68% تحتوى على أعداد تقع ما بين ²10 وأقل من ³10 لکل جرام وبواسطة طريقة MPN وجد أن 3.33% من العينات کانت ملوثة بکل من بکتريا القولون وکذلک بکتريا القولون البرازية، وقد کانت معظم العينات (60%) تحتوى على عدد أقل من 10 والنسبة الباقية (40%) تحتوى على أعداد من کل من هذه البکتريا تراوحت بين 10 وأقل من ²10 لکل جرام. بينما لم يستدل على تواجد ميکروب الايشيريشيا کولاى فى العينات التى تم فحصها. وتم عزل الميکروبات السبحية المعوية بنسبة 10.7%، وکانت تحتوى على أعداد تقع بين أقل من 100 و6׳10 بمتوسط عددى 4.08׳10 لکل جرام، وقد کانت
56.25، 25 و18.75% من العينات المفحوصة تحتوى على أعداد من البکتريا تترواح بين²10 إلى أقل من ³10 ، أقل من ²10 و ³10 إلى أقل من ⁴10 لکل جرام على التوالى. وقد أثبتت هذه النتائج أن عينات مخلوط بودرة الآيس کريم المختبرة لم تتعدى حدود المواصفات القياسية سواء العالمية أو المصرية. هذا وقد تم مناقشة الشروط الصحية الواجب اتخاذها لإنتاج مخلوط بودرة آيس کريم ذو جودة عالية وخالى من الميکروبات الممرضة التى قد تشکل خطورة على صحة المستهلک.

SUMMARY

One hundred and fifty random samples of ice cream mix powder with chocolate, mango, strawberry, vanilla, orange, banana and Nescafe flavors (200 grams weigh each) were collected from different groceries and supermarkets in Assiut City over a period of one year and examined for fecal contamination. Our current results showed that, Enterobacteriaceae were isolated from 38.7% of samples with a minimum of 10², a maximum of 8.7X10² and an average of 3.2X10/g. The highest frequency distribution 46 (79.32%) had numbers of less than
10² cfu/g and 12 (20.68%) had counts ranged from 10²-<10³ cfu/g. Enterococci could be isolated from 10.7% of the examined samples with a minimum, a maximum and an average count of <100, 6X10³ and 4.08X10³/g, respectively. The frequency distribution of positive samples was descending from 9 (56.25%), 4 (25.0%) and
3 (18.75%) containing Enterococci in counts ranged from 10^2-<10^3,  <10² and 10³-<10⁴/g, respectively. Otherwise, 5 (3.33%) samples were contaminated by both coliforms and fecal coliforms with frequency distribution of 3 (60%) that had counts of less than 10/g and 2 (40%) had counts ranged from 10-<10²/g. E. coli could not be detected. Recommendations were suggested to control the presence of such microorganisms in ice cream mix powder samples to avoid their undesirable changes that resulted in economic losses as well as public health hazard.

Key words: Enterobacteriaceac, coliforms, fecal coliforms,Enterococci, contamination, ice cream mix powder.

Introduction

Ice cream is the most palatable, nutritious, healthful and relatively inexpensive dairy food. It is highly appreciable by all ages because it is considered a safe, enjoyable, energy giving and refreshing food because levels of water soluble vitamins and minerals are two to three times higher than those of full cream milk. Also, it is a valuable source of vitamin B, and contains twice vitamin A content as that of milk (Varnam and Sutherland, 1994). Nowadays, ice cream mix powder produced and sold in increasing quantities for manufacturing of ice cream on a large scale, in markets, and it is also purchased for preparation of ice cream at home. Ice cream mix is often stored (aging) for few hours or even overnight; so there is opportunity for bacterial growth and multiplication, rendering the product to be of public health hazard. Because ice cream is consumed without any treatment that might reduce its microbial load, it is necessary to maintain a high level of microbial quality. For this purpose, many countries have adopted mandatory manufacturing practices and standards to ensure an adequate and wholesome supply of such product.

In spite of the high temperature attained in preparation of ice cream mix powder and its low moisture content, its packaging process, addition of additives and flavoring agents, methods of preservation and transportation it may, at times, be responsible for transmitting some pathogenic and food poisoning bacteria to consumers. Their presence in dried milk products provides a useful index in determining the hygienic quality of the products. The presence of coliform bacteria in milk powder has been reported by Leitao et al. (1973); Aleksieva (1974); Jhodekeer and Nambudripad (1975); Jarchovská and Hartmanova (1975); Arun et al. (1980); and Lück et al. (1980). Enterococci organisms have a distinctive role as an indicator of poor factory sanitation; so that, they were enumerated and isolated from milk powder by many workers (Stark, 1970; Leitao et al., 1973; Aleksieva, 1974 and Lück et al., 1980).

As the microbial quality of ice cream mix powder with various

flavoring agents, reflects the care with which milk was produced and the sanitary conditions prevailing during its manufactures, therefore, this work was planned to detect the fecal pollution by determination of Enterobacteriaceae, total coliforms, fecal coliforms, E.coli and Enterococci counts.

Materials and Methods

A-    Collection of the samples:

150 random samples of ice cream mix powder with chocolate, mango, strawberry, vanilla, orange, banana and Nescafe flavors (200 grams weigh each) in retail packages ready for sale were collected from different groceries and supermarkets in Assiut City over a period of one year. The expired date was after 2 years, from the production time. To avoid contamination, the samples were dispatched directly to the laboratory where they were examined microbiologically to evaluate their quality.

B-    Preparation and serial dilution of samples:

Packages of ice cream mix powder were cleaned and being aseptically opened. 11 grams of the ice cream mix powder samples were mixed with 99 ml of sterile 0.1% peptone water and thoroughly mixed to have a dilution of 1/10 from which ten fold serial dilutions were prepared as recommended by A.P.H.A. (1992).

C-    Experimental techniques:

Included:

1-      Enumeration and isolation of Enterobacteriaceae using Violet Red Bile Glucose Agar (VRBGA). (Mercuri and Cox, 1979).

2-      Total coliforms, fecal coliforms and E.coli counts using (MPN). (A.O.A.C., 1975).

3-      Enumeration and isolation of Enterococci using KF streptococcal agar. (Deibel and Hartman, 1976).

D-    Biochemical reactions for Enterobacteriaceae organisms:

Included:

1-      Indol production, Methyl red, Voges-Proskauer, Citrate utilization, H₂S production tests: (Finegold and Martin, 1982)

2-      Urease test: (Edwards and Ewing, 1972)

3-      Glucose and sugar fermentation tests:(Speck, 1976)

Results

The obtained results are recorded in Tables 1-4.

Table 1: Statistical analytical results of Enterobacteriaceae and Enterococci in the examined ice cream mix powder samples.

*Colonies could not be detected on the plates.

Table 2: Frequency distribution of the positive ice cream mix powder samples based on their Enterobacteriaceae and Enterococci count/g.

Table 3: Incidence of coliforms and fecal coliforms in the examined ice cream mix powder samples.

Table 4: Frequency distribution of positive ice cream mix powder samples based on their coliforms and fecal coliforms count (MPN/g).

Discussion

The results recorded in Table 1 revealed that, 58 (38.7%) of the examined ice cream mix powder samples were contaminated by Enterobacteriaceae in counts ranged from <100 to 8.7X10² with an average count of 3.2X10 cfu/g.Table 2 showed that, most of positive samples 46 (79.32%) contained numbers less than 10² cfu/g, while, 12 (20.68%) had counts ranged from 10² to <10³ cfu/g. These counts are in fair agreement with those recorded by Abdel-Haleem (1998) in ice cream mix powder. But in milk powder, Sprang (1969) recorded lower incidence. While, higher counts were conducted by Dardir (2005).

Contamination of large numbers of ice cream mix powder samples with Enterobacteriaceaecould be taken as an index of fecal contamination and also could be attributed to the unsanitary practices, poor hygienic quality of ingredients used and/or may be due to the contamination during packaging.

Regarding the Enterococci counts, it is evident that 16 (10.7%) samples contaminated with Enterococci. The level of contamination varied from <100 to 6X10³ with an average of 4.08X10³ /g. The frequency distribution arranged descending from 9 (56.25%), 4 (25.0%) and 3 (18.75%) samples ranged from 10^2-<10^3, <10² and 10³-<10⁴/g, respectively (Table 1 and 2). Higher counts and incidences were estimated by El-Bassiony and Aboul-Khier (1983) and Abdel-Haleem (1998) in ice cream mix powder samples. While, Aleksieva (1974) recorded higher counts in milk powder samples.

The occurrence of Enterococci in ice cream mix powder samples seems to be illogic, because no acceptable level of these microorganisms could be present, and may be attributed to post manufacture contamination, the heat resistant character of the organisms, and contamination during packaging and/or improper methods of distribution. The public health significance can not be denied, especially, when the organisms found in tremendous number in the product as they have been implicated in several food poisoning outbreaks (International Committee on Microbiological Specification for Foods (ICMSF), 1978).

It is clearly evident from the results illustrated in Table 3,that both coliforms and fecal coliforms could be isolated from 5 out of 150 samples (3.33%). Most of positive samples 3 (60%) contained coliforms and fecal coliforms less than 10 cfu/g. While, 2 (40%) had counts varied from 10-<10² cfu/g (Table 4). Higher incidence of total coliformswas established by El-Bassiony and Aboul-Khier (1983). World Health Organization Standards (1981) reported that coliforms should fail to be detected in the examined ice cream mix powder samples. By comparing these counts with Egyptian Standard (1988), Varnam and Sutherland (1994) and U.S. Dairy Export Council (1996-2002)standards, coliforms counts did not exceed these standards.

In case of fecal coliforms, nearly similar results were recorded by Aleksieva (1974) in infant dried milk samples. In the contrary, El-Prince and Korashy (2003) could not isolate these organisms from the examined milk powder samples.

Fortunately, E. coli could not be detected in all of examined ice cream mix powder samples. Coliforms contamination could be attributed to poor quality ingredients, careless hygiene during packaging. Moreover, coliforms and fecal coliforms still continue to be considered as indicator organisms of choice in examining milk and milk products (Marier et al., 1973).

As good sanitation and strict hygienic measures during processing, packaging, preservation and transportation of these desserts is fundamental, therefore, suggestive measures for control of microorganisms are to be considered to ensure safety and high quality ice cream mix.

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