HYGIENIC STATUS OF SOME MEAT PRODUCTS WITH SOME TRIALS TO IMPROVE THE QUALITY AND EXTEND SHELF LIFE

HYGIENIC STATUS OF SOME MEAT PRODUCTS WITH SOME TRIALS TO IMPROVE THE QUALITY AND EXTEND SHELF LIFE

Morshdy, A.M.A. ;A.F.A. Mahmoud and AyaG.M.Omran

Food Control Department, Faculty of Veterinary Medicine,

Zagazig University, Zagazig, Egypt

Key Words: Meat products, spoilage, Food poisoning, Essential oils

ABSTRACT

Meat products aregood sources of all essential amino acids, B-complex vitamins and minerals. Despite this high biological value, meat products act as good substrates for microbial growth and have been implicated in many foodborne disease outbreaks.Therefore, A total of 80 random samples of minced meat, sausage, burger and luncheon (20 of each), were randomly collected from different markets at Zagazig City, Sharkia governorate,Egypt for bacteriological examinations. Results revealed contamination of the examined products by Pseudomonas, Enterobacteriaceae and Hydrogen sulfide producing bacteria. Furthermore, the antimicrobial activity of some natural oils (cumin, thyme and rosemary oil 1%) were investigated; results revealed that they act as good preservatives to meat. Rosemary oil was the most effective oil followed by thyme then cumin oil.

1. INTRODUCTION

Meat and its products are considered as an excellent source of protein, fat, B-vitamins, Iron, Zinc and Vitamin A as well as the essential amino-acids. Meat products are favored by numerous people groups, but if these products are not processed, packaged, distributed and stored correctly; it will spoil rapidly and represent a risk to consumers' health. Meat products can be contaminated with microorganisms from meat handlers during processes of manufacturing, packing and marketing in addition to improper cooking, refrigeration and storage which may lead to meat borne illness. Pseudomonas spp. are proteolytic microorganisms, they can separate protein, delivering an assortment of smell and flavor deteriorations as well as slime appearance on meat surfaces. The Enterobacteriaceae is a family of Gram-negative, non-spore-forming bacteria and is a standout amongst the most critical gatherings of microscopic organisms known to man which are the most dominating species in all food contamination cases related with some meat products.Hydrogen sulfide-producing bacteria include a wide assortment of bacterial species that are universal in the earth and can develop in high protein products such as meat and meat products. They can prompt generation of hydrogen sulfide, which is dangerous to wellbeing. These include H₂S producing microorganisms include Pseudomonas spp., Citrobacter spp., Aeromonas spp., Salmonella spp. and Escherichia coli(Atterburyet al., 2007).

Essential oils are aromatic and oily liquids that are extracted from different parts of plant materials, (seeds, leaves and fruits)(Gutierrez et al., 2008). These substances had various antimicrobial activities as they act mainly on the cytoplasmic membrane of the bacterial cells in addition to hydroxyl group related to the deactivation of many enzymes. Furthermore, this group can cause loss of cell component, changes on fatty acids and phospholipids, and antagonize energy metabolism and genetic materials synthesis (Di Pasquaet al., 2005). Among these essential oils, rosemary (Rosmarinusofficinalis L.) oil which is broadly utilized to preserve meat and meat products. Thyme (Thymus vulgaris L.) is an aromatic herb belongs toLabiateae family, utilized in foods for many purposes. The most important compounds of thyme are the phenols thymol (44-60%) and carvacrol (2.2-4.2%), as well as the monoterpene hydrocarbons ρ-cymene (18.5-23.5%) and γ-terpinene (16.1-18.9%) (Di Pasquaet al., 2005); these active have antimicrobial action against a wide range of gram negative or positive bacteria (Ozcanet al., 2003). Cumin (Cuminumcyminum L.) is a flavor generally utilized as a germicide specialist, and it additionally has an amazing antimicrobial action on various types of microscopic organisms, pathogenic and non-pathogenic growths for people (De et al., 2003).Subsequently, the present investigation was planned to evaluate to what degree meat products in Sharkia Province are bacteriologically contaminated in addition to determine the antimicrobial activity of cumin, thyme and rosemary oil 1%.

1. MATERIALS AND METHOD

Collection of samples

A total of 80 random samples of minced meat, sausage, burger and luncheon (20 of each), were randomly collected from different markets in Zagazig City, Sharkia governorate,Egypt. All collected samples were immediately transferred, aseptically handled and moved promptly to Food Control lab for, bacteriological and chemical examination.

Preparation of samples:

According to technique recommended byAPHA(2001).

Determination of Pseudomonas count:

On Pseudomonas Agar Base (CM 559; Oxoid) supplemented with cetrimide, fucidin, and cephaloridine (CFC) supplements (Roberts and Greenwood, 2003).

Determination of Enterobacteriaceae count:

On violet red bile glucose agar (VRBG) agar(ISO, 2004)

Determination of Hydrogen Sulphide producing bacteria count:

On iron agar Lyngby (CM 964; Oxoid, Basingstoke, Hampshire, UK) according to Gram et al. (1987).

Evaluation of the effect of some essential oils on the quality of minced meat:

The selected oils arecumin oil 1% (Cuminumcyminum L.), thyme oil 1% (Thymus vulgaris L.) and C. rosemary 1%(Rosmarinusofficinalis L.). These oils were obtained from the squeezing and extraction of natural oils in the National Research Center, Dokki, Giza.

Design of the experiment:

In the laboratory, minced meat was divided into four equal groups:

1. Control group: 500 grams of minced meat, separated to five clean Ziploc bags.

2. Cumin treated group: 500 grams of minced meat mixed and gently massaged by hand for the homogenous distribution with 5 m1 of cumin oil to obtain final concentration 1% then separated to five clean Ziploc pages.

3. Thyme treated group: 500 grams of minced meat mixed and gently massaged by hand for the homogenous distribution with 5 m1 of thyme oil to obtain final concentration 1%, then separated to five clean Ziploc pages.

4. Rosemary treated group: 500 grams of minced meat mixed and gently massaged by hand for the homogenous distribution with 5 ml of rosemary oil to obtain final concentration 1% then separated to five clean Ziploc pages.All the groups were sampled immediately after treatment (zero time) and every 48 hours. All groups were kept in afridge at 4° C.

Statistical analysis.

One way analysis of variance (ANOVA) was done by using the statistical package for social sciences (SPSS-14; Chicago, IL, USA). Statistical significance was evaluated using tukey-kramer honestly significant difference tests with p < 0.05.

3.RESULTS

A. Bacteriological evaluation of meat products

Results in Table (1) declared that the meancount ofpseudomonas in the examined minced meat, sausage,burger and luncheon samples was4.8 ± 0.092, 3.7 ± 0.1129, 3.5± 0.1978 and  2.7± 0.1288Log₁₀CFU/g, respectively.While, the mean count of Enterobacteriaceae was4.2 ± 0.1294, 3.6 ± 0.1059, 3.2 ± 0.1510and 2.7 ± 0.1628Log₁₀CFU/g in the examined minced meat, sausage,burger and luncheonsamples, respectively (Table 1).

Table (1) Bacteriological examination of some meat products (n=20 of each) log₁₀ CFU/g

n: number of the examined samples, CFU/g: Colony Forming Unit per gram S.E: Standard error of mean, (a, b, c and d): Means within the same column bearing different superscript letters are significantly different (P< 0.05).

It was found that, the mean count of hydrogen sulphide producing bacteria was 4.3 ± 0.0921, 3.1± 0.1306, 3.3 ± 0.0985 and2.5 ± 0.0935Log₁₀CFU/g in the examined minced meat, sausage,burger and luncheonsamples, respectively.

B.Effect of cumin, thyme and rosemary oil 1% on bacteriological quality of minced meat:

Pseudomonascounts of control untreated samples gradually increased along storage period; the initial Pseudomonascount value was 4.19±0.1925Log₁₀CFU/g(Figure 1), while it increased to 4.93± 0.0712,5.69± 0.1867 and 7.08± 0.3298Log₁₀CFU /g at the 3^rd, 5^th and 7^thday of storage, respectively(Figure 1). Pseudomonascounts in treated samples by cumin, thyme and rosemary oil1% at zero daywas 4.08±0.1672, 3.98±0.0454 and 3.83±0.1514 Log₁₀CFU/g, respectively.Rosemary oil1% was the most effective in Pseudomonas reduction followed by thyme oil 1% >cumin oil 1%.By the third day of storage, treatment by thyme and rosemary oil 1% proved significant reduction (p<0.05) in pseudomonascount;it was 4.28±0.0352 and 3.04±0.2783Log₁₀CFU/g. Meanwhile at the 5^th day, the three treatment trials proved significant reductions in Pseudomonascounts (p<0.05). It ranged from 4.94 to 5.48, 4.38 to 5.42 and 4.20 to 4.90 Log₁₀CFU/g after treatment by cumin, thyme and rosemary oil 1%, respectively.By the 7^th day of storage, after treatment by cumin, thyme and rosemary oil 1%,Pseudomonascounts reduced to 6.13±0.2427, 5.87±0.1154 and 5.19±0.2131Log₁₀CFU/g, respectively (Figure 1).

Figure (1): Effect of Cumin, Thyme and Rosemary oil 1% on Pseudomonas count (log CFU/g) of chilled minced beef meat samples at 4±1^° C at zero, 3^rd, 5^th, and 7^th day.

Enterobacteriaceaecounts after treatment by cumin, thyme and rosemary oil1% at zero daywas3.99±0.2220, 3.96±0.1456 and 3.74±0.1006 Log₁₀CFU/g, respectively(Figure 2).By the third day of storage, treatment by thyme and rosemary oil 1% proved significant reduction (p<0.05) in Enterobacteriaceaecounts ranged from 3.63 to 4.6 3 and 3.11 to 4.45 Log₁₀CFU/g. However, treatment by cumin oil 1% was the lowest in Enterobacteriaceae reduction. Meanwhile at the 5^th day, after treatment by rosemary oil 1%, Enterobacteriaceaecount reduced to 4.30±0.0706Log₁₀CFU/g(Figure 2).While, after treatment by cumin and thyme oil 1%, Enterobacteriaceae count was5±0.0815 and 4.84±0.1831 Log₁₀CFU/g, respectively. By the 7^th day of storage, treatment by cumin, thyme and rosemary oil 1% reduced Enterobacteriaceae counts to 5.83±0.1676, 5.74±0.1102 and 5.41±0.1702 Log₁₀CFU/g, respectively. (Figure 2).

Figure (2): Effect of Cumin, Thyme and Rosemary oil 1% on Enterobacteriaceae count (log CFU/g)of chilled minced beef meat samples at 4±1^° C at zero, 3^rd, 5^th, and 7^th day

The counts of H₂S producing bacteria of control untreated samples gradually increased along storage period; it was3.63±0.0439 Log₁₀CFU/g(Figure 3). By the third day, the count increased to 5.03±0.1927 Log₁₀CFU/g. While, at the 5^th day of storage the counts of H₂S producing bacteriawas 5.60±0.1791Log₁₀CFU/g(Figure 3). By the 7^th day, the count highly increased to 6.60±0.1576 Log₁₀CFU /g. Concerning to treated samples,the counts of H₂S producing bacteria after treatment by cumin, thyme and rosemary oil1% at zero daywas3.56±0.0444, 3.35±0.1027and 3.15±0.1184 Log₁₀CFU/g, respectively.Rosemary oil1% was the most effective in reduction of H₂S producing bacteria followed by thyme oil 1% >cumin oil 1%.Meanwhile at the third day, after treatment by rosemary oil 1%, the counts of H₂S producing bacteria decreased to 4.79±0.1050Log₁₀CFU/g. While, after treatment by cumin and thyme oil 1%, the counts of H₂S producing bacteriawas 4.71±0.1501 and 4.19±0.1667 Log₁₀CFU/g, respectively.By the 5^th day of storage, the counts were4.96±0.2610, 4.83±0.1322 and 4.47±0.1424 Log₁₀CFU/g. However at the 7^thafter treatment by cumin, thyme and rosemary oil 1%, the counts of H₂S producing bacteria decreased to 6.42±0.1952, 6.10±0.2262 and 5.49±0.1704 Log₁₀CFU/g, respectively(Figure 3).

Figure (3): Effect of Cumin, Thyme and Rosemary oil 1% on Hydrogen Sulphide (H₂S) producing bacteria count (log CFU/g) of chilled minced beef meat samples at 4±1^° C at zero, 3^rd, 5^th, and 7^th day

4.  DISCUSSION

Meat spoilage and foodborne diseases pose a serious threat to the public health causing huge economic losses. Pseudomonas spp., are used as general pointers of hygiene in meat industries because they have the ability to release spoilage indicator as nitrogenous compounds, including primary, secondary and tertiary amines.

It was found that, minced meat samples had the highest count of Pseudomonas. This result was in line with El-Said (2010) and, El-Shopary (2010). On the other hand, higher result (6.25 log₁₀CFU/g) was detected by Erdemet al. (2014). However, lower results (2.85 and 3.11 log₁₀CFU/g)were detected by Zhangaet al. (2011) and Gaafaret al. (2012), respectively.

Concerning to sausage samples, Pseudomonas count recorded in this study was nearly similar to what had been reported by  El-Said (2010), Gaafaret al. (2012) and Sofyet al. (2017) who found the mean count of Pseudomonas in the examined sausage samples was 3.5, 3.5 and 3.88 log₁₀CFU/g, respectively. But lower result (3.3 log₁₀CFU/g) was recorded by El-Shopary (2010).Contamination of the examined burger samples was in accordance with El-Shopary (2010), Gaafaret al. (2012) andSofyet al. (2017),but disagreed with El-Said (2010) who detected higher count. The examined luncheon samples had the lowest count of pseudomonas compared with the other samples. In contrast to this result, higher counts of (4 and 3.6 Log₁₀ CFU/g) in luncheon samples were detected by El-Shopary (2010) and Sofyet al. (2017).Contamination with Pseudomonas spp. attributes to inappropriate handling by food handlers during the different stages of production as well as inadequate storage temperature.

Enterobacteriaceae are considered as indicator bacteria to evaluate the hygienic condition of meat. Minced meat samples had a high count of Enterobacteriaceae compared with other samples. This result agreed with El-Sheikh (2014), however, lower results (3.4 Log₁₀ CFU/g) was registered by Gaafaret al. (2012). On the other side, higher result (4.92 Log₁₀ CFU/g) was detected by Kilonzo-Nthengeet al. (2013). Concerning to sausage samples, the mean count of Enterobacteriaceae was consistent with Gaafaret al. (2012) and Sofyet al. (2017).Meanwhile, Mousaet al. (2014) reported lower result (2.9 Log₁₀ CFU/g). However, higher counts were detected by El-Sheikh (2014)(4.9CFU/g)in sausage samples. Regarding to burger samples, Enterobacteriaceaecount corroborated previous works conducted by Guillieret al. (2013) and Sofyet al. (2017). On the other side, higher results of 5.4 Log₁₀ CFU/g were registered by Gaafaret al. (2012). Meanwhile, lower counts (2.7 and 2.13 Log₁₀ CFU/g) were detected by Mousaet al. (2014) and Shaltoutet al. (2017).In the examined luncheon samples, theEnterobacteriaceaecount was lower than all examined samples. Nearly similar result was reported by Samahaet al. (2016), but,this result disagreed with Zaghloulet al. (2014) and Sofyet al. (2017) who reported higher counts of Enterobacteriaceae (3.6 and 4.55 Log₁₀ CFU/g).Contamination with family Enterobacteriaceae is an indicative of unhygienic environment like sewage, improper waste disposal systemas well as contamination of meat handler's hands, tools and handling surfaces.Members of the family Enterobacteriaceae are potent causes of foodborne diseases and might pose a health risk to consumers.

Different species of bacteria (Pseudomonas spp., Citrobacter spp., Aeromonas spp., Salmonella spp. and Escherichia coli) are able to convert sulfur-containing amino acids into hydrogen sulphide (H₂S) which is a colorless and irritant gas with a characteristic odor of rotten eggs. Minced meat samples had a high count of hydrogen sulphide producing bacteria, followed by burger then sausage samples, while, luncheon samples had the lowest count of hydrogen sulphide producing bacteria. Many other previous investigations reported contamination of meat products by hydrogen sulphide producing bacteria as Vogel et al. (2005) andNychaset al. (2008). Contamination of meat products by hydrogen sulphide producing bacteria could be attributed to inadequate practices, mainly poor hygienic conditions. Also, unsanitary preparation places, inadequate clean utensils, cross contamination from raw meat, poor personal hygiene and hygienic practices of meat handlers.

Plant extracts such as essential oils have indicated antimicrobial activity against both foodborne pathogenic and spoilage microorganisms (Hashemiet al., 2017). Results in the present study indicated a comparison of effectiveness of cumin, thyme and rosemary oil 1%used separately on the count pseudomonas, Enterobacteriaceae and hydrogen Sulphide producing bacteriaof raw minced meat samples stored at 4 °C. These oils proved their effectiveness in meat preservation, reduction of bacterial count and extend the shelf life.These results were in accordance with Conner (1993) who reported that the essential oils of thyme and rosemary were shown to possess strong antibacterial activity against Pseudomonas aeruginosa. However Elgayyaret al. (2001) reported the antibacterial potential of rosemary essential oils against meat spoilage bacterial pathogens such as Pseudomonas fluorescensand P. aeruginosa, respectively.Agaogluet al. (2007) revealed that the extracted essential oils of cumin showed an antimicrobial effect against Pseudomonas aeruginosa. While, Karabagiaset al. (2011) reported the inhibitory effect of cumin and thyme on Pseudomonas spp.Concerning to the effect of the essential oils on Enterobacteriaceae count, nearly similar results were registered by Imelouaneet al. (2009) who reported that thyme oil has been shown to effectively inhibit food-borne pathogens of familyEnterobacteriaceae. Meanwhile, Djeddiet al. (2007) reported that Enterobacteriaceae were susceptible to the activity of rosemary essential oil. Rasool (2013) stated that the extracted essential oils of cumin showed an antimicrobial effect against members of family Enterobacteriaceae. cumin, thyme and rosemary oil 1% were effective in reduction of hydrogen Sulphide producing bacteria. Similar results were obtained by Viuda-Martoset al.(2010). Also, Solomakoset al. (2008) illustrated thatdifferent concentrations (0.3, 0.6 or 0.9 %) of thyme essential oil successfullyinhibited the bacterial growth in treated minced beef.It was found that rosemary oil 1% was the most effective oil in meat preservation followed by thyme oil then cumin oil.The reduction in the count of pseudomonas, Enterobacteriaceae and hydrogen sulphide producing bacteriaafter treatment of minced meat by cumin, thyme and rosemary oil 1%, attributed to the antimicrobial activities of the phenolic compounds of these oils against wide range of bacteria. Therefore, these oils especially rosemary oil act as good preservatives to improve the shelf life of meat products.

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الحاله الصحیه لبعض منتجات اللحوم مع بعض  المحاولات لتحسین حالتها الصحیه واطاله مده حفظها

علاء الدین محمد مرشدى، عبدالله فکرى عبدالله محمودوآیه جمعه عمران

قسممراقبة الأغذیة کلیةالطبالبیطریجامعةالزقازیقمصر

تُعد اللحوم  ومنتجاتها من أهم الأغذیة التی یحتاج إلیها الإنسان نظراًلقیمتها الغذائیة العالیة فهی تعتبر مصدرًممتازًللعدید من العناصر الغذائیة ؛ خاصة البروتین والدهون والفیتامینات والحدید والزنک بالإضافة إلی العدید من الحموض الأمینیة الأساسیة التی تلعب دورًا أساسیًا فی بناء وإصلاح جمیع أنسجة الجسم.لذا إشتملت هذه الدراسة على جزئین أساسیین تناول الجزء الأول منها فحص الحالة الصحیة لبعض منتجات اللحوم المتداولة بأسواق مدینة الزقازیق حیث تم تجمیع عدد 80 عینة من منتجات اللحوم (اللحم المفروم، السجق، البرجر، اللانشون) بواقع 20 عینة من کل نوع علی  حده لفحصها بکتیریولوجیًا. بینما تناول الجزء الثانى بعض المحاولات لتحسین الحالة الصحیة لبعض منتجات اللحوم (اللحم المفروم) بواسطةإستخدام بعض الزیوت الطبیعیة مثل زیت الکمون وزیت الزعتر وزیت إکلیل الجبل (الروزماری) بترکیز 1% من کل نوع. أظهرت النتائج تلوث العینات بالبکتریا مع زیادة فی العد الکلی لکل من السودوموناس والبکتیریا المعویة وأیضاالبکتریا المنتجة لغاز کبریتید الهیدروجین. کما أظهرت أیضاً کفاءة الزیوت التی إستخدمت فی تحسین الحالة الصحیة للحم المفروم وزیادة فترة حفظه. خلصت الدراسة إلى أن استخدام بعض الإضافات مثل زیت الکمون 1% وزیت الزعتر 1% وزیت الروزماری 1%  یؤدى إلى إطالة مدة الصلاحیة وتقلیل الحمل المیکروبى فى منتجات اللحوم , لذا نوصى باستخدام تلک الإضافات فى التصنیع.وننصح بإستخدامهم فی حفظ منتجات اللحوم.