Microbiological and Chemical Properties of Cheese Helva Produced in Turkey

Abstract

In this study, the microbiological and chemical properties of Cheese helva, one of the traditional cheeses varieties produced in Turkey, was studied. This cheese is called Cheese helva since it is produced from wheat flour and milk cream. Samples were randomly collected from different villages in the Erzurum province of Turkey. The average of total aerobic mesophilic bacteria (TAMB), yeast and mould, yeast, lactic acid bacteria (LAB), proteolytic bacteria, and lipolytic bacteria were determined 4.9 × 10⁷, 6.4 × 10⁴, 3.5 × 10³, 7.6 × 10⁶, 4.6 × 10³, and 8.6 × 10³ cfu/g, respectively. 44.44% of the Cheese helva samples had no coliform; the samples that were positive for coliform showed an average of 5.1 × 10³ cfu/g. Staphylococcus aureus was found < 10 cfu/g in analyzed samples. The Cheese helva was characterized by dry matter as 84.32 kg/100 kg cheese, fat as 37.44 kg/100 kg cheese, protein as 13.75 kg/100 kg cheese, NaCI as 0.58 kg/100 kg cheese, titratable acidity as 0.210%, pH as 5.30, ash as 1.49 kg/100 kg cheese, and carbohydrate as 38.56 kg/100 kg cheese. Cheese helva was found to have a high variation based on chemical composition. The microbiological tests revealed that there were high amounts of total bacteria, yeast and molds, molds, lactic acid bacteria, lipolytic bacteria, proteolytic bacteria, and coliforms.

Keywords:

• Cheese helva
• Microbiological and Chemical properties

INTRODUCTION

Cheesemaking began about 8000 years ago and now there are in excess of 1000 cheese varieties worldwide, each unique with respect to its flavor and form.[1] There are about 50 types of cheeses traditionally produced in Turkey; in addition, there are many commercial varieties produced, such as white cheese, Kashar cheese, and Tulum cheese.[2] Manufacture of most cheese varieties involves combining four ingredients: milk, rennet, microorganisms, and salt.

Cheese helva, one of the traditional cheese varieties in Turkey, is produced using alternative methods. It is manufactured especially in small family businesses in the Erzurum province of Turkey for family needs and not for commercial purposes. Starter culture is not used in the manufacture of this product. Generally, it is consumed for breakfast, with or without bread. Cheese helva, a semi-hard cheese variety, has a fibered structure. Its color varies from light brown to dark, depending on the processing conditions, and it is produced from Civil cheese, wheat flour, and milk cream. This cheese is called Cheese helva because it is produced from wheat flour, milk cream or butter, and salt. Since the production method for Cheese helva is not standardized, significant variations may be observed during the processing conditions and product.

Civil cheese is the main component in the manufacturing of Cheese helva, and Civil cheese is manufactured before Cheese helva production. Civil cheese should be fresh and unsalted. Civil cheese, an acid curd with rennet added, is a popular cheese variety in Turkey and generally produced in the eastern Anatolian region of Turkey.[3,4] Civil cheese is produced from skim milk. A major part of the skim milk, especially from butter production, in dairy plants is processed into Civil cheese to get an important additional economic profit. Civil cheese is somewhat similiar to Pasta filata cheeses, having a unique plasticizing and kneading treatment of the fresh curd in hot water, which gives the product a fibrous structure and melting and stretching properties.[5] The various parameters of the Civil cheese are chracterized as dry matter of 40.18 kg/100 kg cheese, fat 0.15 kg/100 kg cheese, protein 29.17 kg/100 kg cheese, NaCI 6.14 kg/100 kg cheese, acidity (°SH) 13.77, pH 6.32, and ash 0.84 kg/100 kg cheese.[6] The production of Cheese helva is carried out in two stages: Civil cheese production and preparing the Cheese helva mixture (Fig. 1).

Figure 1 Production of Cheese helva.

Production of Civil Cheese (Stage I)

Traditionally, Civil cheese is made from skim milk without starter culture. Acidity of skim milk is adjusted to 22 Soxhlet Henkel (°SH), after the skim milk is allowed to rest overnight at about 15°C to increased its acidity by natural microflora. Skim milk is heated up to 30°C and rennet is added very slowly to the skim milk (approximately, 100 ml milk/4 ml rennet) for coagulation. In traditional Civil cheese production, starter culture is not used. As the heating process is slowly increased with a slow agitation, the curd forms at about 52–53°C. Curd particles are facilitated stick to ladle with mixing process. The heating process is carried on until the temperature reaches about 70°C and after the coagulation, the curd forming has a fibrous form as a result of the mixing and lengthening process. The cheese block is transferred to a clean surface by the paddle and kneaded by hand. The fibered cheese is then hung up to release its water for 24 hours by its own weight.[6] The stretching process is repeated until the curd has a smooth, plastic, and fibrous character.

Production of Cheese Helva (Stage II)

After production of Civil cheese, the Cheese helva mix is prepared. The mixture is composed of Civil cheese, milk cream or butter, wheat flour, and salt. First, milk cream is melted by heating. Then, the milk cream is mixed by adding little amount of salt (1%) while the heating process carries on. This process is continued approximately for 6 minutes. Then, wheat flour is added to the mixture and mixing process is facilitated by heating. The heating process continues until light brown color appears (approximately 15 minutes). Then, the mixture is left to cool until it reaches about 70–80°C. After the cooling process, fibered-Civil cheese is added to the mixture, and the mixture is completely mixed in order to obtain a homogenous structure (Figure 1). Finally, it is served warm or cool. Negligible research has been performed on Cheese helva. Neither the technique for producing the cheese, nor the microbiological or chemical composition of the cheese has been described previously. Therefore, the aim of this article was to determine its microbiological and chemical states, as well as to introduce the manufacture of Cheese helva. No standard is available for this type of cheese in Turkey.

MATERIALS AND METHODS

Samples

The samples were randomly collected from different villages in the Erzurum province of Turkey and were transported to the laboratory in an ice chest. Then samples were labelled, stored at 5°C, and were examined within 24 hours.

Microbiological Analysis

Eleven grams of each sample of Cheese helva was homogenized for 1.5 minutes with a Waring Blender in 99 ml-2.0% sodium citrate solution. Serial dilutions were prepared in 0.1 sterile peptone water, and duplicate plates were used for all determinations. In the microbiological analysis for Cheese helva, the media and conditions of incubation used were as follows: a) Total aerobic mesophilic bacteria (TAMB), Plate Count Agar (PCA, Oxoid), 32 ± 1°C/48 ± 3 h.[7] b) Yeast and molds, Potato Dextrose Agar (PDA, Oxoid, pH adjusted at 3.5 with tartaric acid), 21 ± 2°C/7 d.[7,8] c) Yeast counts, Oxytetracycline Glucose Yeast Extract Agar (OGYEA, Oxoid), 25 ± 1°C/5 d.[9] d) Lactic acid bacteria (LAB), de Man Rogosa, Sharpe Agar (MRSA, Oxoid), 30 ± 1°C/48 h.[8,10] e) Lipolytic microorganism, Blue Sulfate Agar (BSA, Oxoid), 32 ± 1°C/5 d.[7,8] f) Proteolytic bacteria, Casein Agar (CA, Oxoid), 32 ± 1°C/5 d.[7, 8] g) Coliforms counts, Violet Red Bile Agar (VRBA, Oxoid), 32 ± 1°C 48 h.[7,8] h) Staphylococcus aures counts (Staph. aures) (Staphylococcus medium 110, Oxoid), 37°C/48 h.[7]

Chemical Analysis

Cheese helva samples were analyzed for dry matter, fat, protein, sodium chloride, titratable acidity, pH, and ash according to Kurt et al. (1993).[11] Carbohydrates were ascertained using a polarimeter, according to Yetim (2002).[12]

Statistical Analysis

To estimate the variability in chemical composition of Cheese helva, some statistical parameters including mean, standard error, range, standard deviation, and coefficient of variation for each index were determined.[13]

RESULTS AND DISCUSSION

Some chemical and physical characteristics of the Cheese helva are presented Table 1. The dry matter, protein, carbohydrate, and fat contents in the analyzed samples were very high (Table 1). Since Cheese helva contains high amounts of protein and fat, it could be an important food product for human nutrition. Dry matter, fat, protein, and ash content in samples analyzed was found to be between 77.60 and 88.09 kg/100 kg cheese, 33 and 50 kg/100 kg cheese, 10.11 and 15.60 kg/100 kg cheese, 0.77 and 2.49 kg/100 kg cheese, respectively (Table 1).

Table 1 Some chemical and physical characteristics of Cheese helva.

Statistical parameters	Dry matter (kg/100 kg cheese)	Fat (kg/100 kg cheese)	Protein (kg/100 kg cheese)	NaCI (kg/100 kg cheese)	Acidity	pH	Ash (kg/100 kg cheese)	Carbohydrate (kg/100 kg cheese)
x ^a	84.32	37.44	13.75	0.58	0.210	5.30	1.49	38.56
Range	77.60–88.09	33.00–50.00	10.11–15.60	0.23–1.14	0.18–0.27	4.85–5.71	0.77–2.49	38.0–39.4
SEX ^b	1.35	1.88	0.53	0.11	0.01	0.09	0.18	0.09
Sd ^c	4.05	5.05	1.59	0.31	0.04	0.29	0.54	0.38
CV ^d	4.80	13.48	11.55	53.45	21.40	5.39	36.17	0.96
n ^e	9	9	9	9	9	9	9	9

High differences were determined in the fat content among samples examined. This difference in the fat content may be due to the fact that this product does not have a standard production technique and also the use of varying raw materials. Bakirci and Andiç[14] determined the fat ratio in Çeçil cheese as between 0.1–0.9 kg/100 kg cheese. The fat values obtained from Cheese helva samples are much higher than the values found by Kurt and Öztek[15] and Çağlar et al.[6] The high fat ratio in Cheese helva is derived from the use of cream in cheese production. Since Cheese helva is traditionally manufactured cheese type, there is not any standard for this product in our country. When the samples compared within the TS-3001 Tulum Cheese Standard,[16] however, it can be seen that seven samples of fatty cheese (at least 30 kg/100 kg cheese fat in dry matter) and two samples of fat rich cheese (at least 45 kg/100 kg cheese fat in dry matter) fulfill the standard. In the analyzed samples, the protein content was measured with a minimum of 10.11 kg/100 kg cheese, a maximum of 15.60 kg/100 kg cheese, and an average of 13.75 kg/100 kg cheese. Çağlar et al.,[6] determined the average protein content in fresh Civil cheese to be 30.52 kg/100 kg cheese. These values are higher than the values we found in our Cheese helva; this may be due to the high fat percentage in the analyzed Cheese helva samples.

As it can be seen in Table 1, the ash content in the samples is about 1.49 kg/100 kg cheese. The average ash content determined by Kurt and Öztek[15] was 6.25 kg/100 kg cheese. However, Bakirci and Andiç (1999)[14] determined this content as 9.40 kg/100 kg cheese. The ash ratio in Cheese helva samples is much lower than it is in Çeçil cheese. That difference is due to the use of salt-free Civil cheese in the production of Cheese helva. The acidity value in the analyzed samples was determined to be about 0.21% and the pH 5.30. Kurt and Öztek (1976)[15] determined the acidity values in Civil cheese samples to be 0.83% at the least and 3.80% at the most; the average was 1.83%. As for Çağlar et al.,[6] they found the average acidity value in Civil cheese to be 5.72%. The values in our study were very low compared to those in other studies; we believe this is due to the fact that fresh Civil cheese was used in the production of Cheese helva. The differences in dry matter, protein, fat, and ash contents in Cheese helva samples results from the different origins of raw materials and the non-standard production of Civil cheese. It can be concluded that Cheese helva has a high nutritional value due to higher dry matter, fat, protein, and carbohydrate contents.

The total aerobic mesophilusbacteria, yeasts and molds, yeast, lactic acid bacteria, proteolytic and lipolytic bacteria, coliforms, and Staphylococcus aureus numbers of Cheese helva are shown in Table 2. In general, the number of (TAMB) in the samples analyzed was very high. However, heating process may have affected TAMB counts in Cheese helva. While the least TAMB count was found as 2.0 × 10⁶ cfu/g, the highest as 2.0 × 10⁸ cfu/g (Table 2). Sert and Kivanç[17] determined that the minimum, maximum, and average numbers of total bacteria in 24 Civil cheese samples collected from Erzurum province of Turkey were 2.1 × 10⁷, 8.9 × 10⁹, and 8.5 × 10⁸ cfu/g, respectively. Bakirci and Andic[14] found that Çeçil cheese samples contained a wide range of microorganisms varying from 1.0 × 10⁶ cfu/g to 9.20 × 10⁸ cfu/g, with an average 2.61 × 10⁸ cfu/g TAMB. Civil cheese is named as Çeçil cheese in Mu4 province of Turkey. A comparasion of the means also showed that count of TAMB was lower than Tulum and White cheese.[18,19,20]

Table 2 The results for the microbiological properties of Cheese helva (cfu/g).

Number of samples	Total bacteria	Yeast and Molds	Yeast	Lactic acid bacteria	Proteolytic bacteria	Lipolytic bacteria	Coliforms	Staph. aureus
1	2.0 × 10^6	6.0 × 10^3	4.2 × 10^2	4.2 × 10^5	2.0 × 10^3	1.7 × 10^4	< 10	< 10
2	1.4 × 10^7	2.0 × 10^3	6.0 × 10^2	3.5 × 10^5	1.4 × 10^3	8.5 × 10^3	< 10	< 10
3	8.5 × 10^6	6.5 × 10^4	1.8 × 10^3	2.1 × 10^5	1.0 × 10^2	2.5 × 10^3	< 10	< 10
4	2.0 × 10^8	1.0 × 10^3	1.7 × 10^3	5.6 × 10^5	1.0 × 10^3	6.8 × 10^3	< 10	< 10
5	3.3 × 10^7	8.5 × 10^3	7.0 × 10^3	2.1 × 10^7	1.1 × 10^4	1.3 × 10^4	1.5 × 10^4	< 10
6	1.4 × 10^8	2.0 × 10^3	1.2 × 10^4	1.7 × 10^7	1.0 × 10^3	1.5 × 10^4	9.6 × 10^3	< 10
7	2.8 × 10^7	1.0 × 10^4	7.3 × 10^3	2.8 × 10^7	8.0 × 10^3	3.0 × 10^3	7.0 × 10^2	< 10
8	6.7 × 10^6	3.2 × 10^3	5.3 × 10^2	2.5 × 10^5	1.4 × 10^4	3.0 × 10^3	1.0 × 10^2	< 10
9	1.3 × 10^7	4.8 × 10^5	2.5 × 10^2	5.5 × 10^5	3.0 × 10^3	9.0 × 10^3	1.0 × 10^2	< 10
Average	4.9 × 10^7	6.4 × 10^4	3.5 × 10^3	7.6 × 10^6	4.6 × 10^3	8.6 × 10^3	5.1 × 10^3	< 10

Yeast and mold populations were found higher than that of the yeast population. The yeast and mold counts of Cheese helva samples ranged between 1.0 × 10³ and 4.8 × 10⁵ cfu/g. In this study, it was determined that the number of yeast between 2.5 × 102 and 1.2 × 10⁴ cfu/g, with an average of 3.5 × 103 cfu/g. Bakirci and Andic[14] reported that the average yeast and mold content in 15 Çeçil cheese samples was 7.17 × 10⁵ cfu/g. The yeast and mold counts were high due to unsuitable aseptic conditions during production. The incidence of yeasts and molds has been considered a common and recurrent problem during the aging process and the refrigerated storage of cheese. The incidence of coliform bacteria varied from sample to sample. 44.44% of the Cheese helva samples had no coliform, while the coliform positive samples showed an average value of 5.1 × 10³ cfu/g. Sert and Kivanç[17] determined coliforms in 87.5% of Civil cheese samples. Bakirci and Andic[12] reported that 73.33% of 15 Çeçil cheese samples obtained from retailers in the Mu4 province of Turkey contained coliform bacteria. Coliform bacteria are not expected to exist due to the heating process in the production of Cheese helva. Total coliform count would serve as a good indicator for hygienic quality. The presence of coliform group bacteria in cheese are undesirable because they cause structural defects in the cheeses.

Staphylococcus aureus were found < 10 cfu/g in all samples analyzed. Sert and Kivanç[17] determined the average number of Staphylococcus aureus in 24 Civil cheese samples samples to be 19.2 cfu/g. Cheeses are considered to be an excellent substrate for staphylococcal growth.[21] Staphylococcus aureus may cause food-borne poisoning, when it is exceeds 1.0 × 10⁶ cfu/g; therefore, the presence of Staphylococcus aureus is undesirable.[22] The Lactic Acid Bacteria (LAB) count was found to be very high, ranging between 2.1 × 10⁵ and 2.1 × 10⁷ cfu/g. Guizani et al.,[23] also found the total bacteria counts of Camembert cheese were high in the cheese throughout a 30-day ripening period, with lactic acid bacteria being the main microbial. The microbial levels in various Turkish cheeses have been reported; but, there is no research concerning lactic acid bacteria in Cheese helva. Lactic acid bacteria plays a important role in ripening of cheese due to lactic acid fermentation. It is impossible to prevent growth of coliform and especially proteolytic microorganisms in the absence of LAB.[24] As shown in Table 2, the count of lipolytic bacteria (8.6 × 10³ cfu/g) was found to be higher than that of proteolytic bacteria (4.6 × 10³ cfu/g). While lipolytic bacteria count ranged between 2.5 × 10³ and 1.7 × 10⁴ cfu/g, proteolytic bacteria count ranged between 1.0 × 10², and 1.4 × 10⁴ cfu/g. This is due to the higher fat content in Cheese helva. The high number of lypolitic microorganisms in samples may stem from the containers, unsuitable storage conditions, and the high fat ratio in samples. Some microorganisms are objection able in food because of the fact that there are some strains of proteolytic microorganisms; these may cause economic losses.[25] However, some types of foods like cheese cannot be consumed without proteolitic microorganisms. The proteolytic microorganisms present in Cheese helva are likely due to the Civil cheese used in the production, as well as from the containers and the air.

CONCLUSIONS

The Cheese helva contained high dry matter (84.32 kg/100 kg cheese) and fat (37.44 kg/100 kg cheese). Cheese helva was found to have many variations based on chemical composition. This can be explained by either different composition of raw milk or no available standard production methods. There were significant differences among samples based on dry matter, fat, and proteins. It can be also concluded that Cheese helva has a high nutritional value due to its higher dry matter, fat, protein, and carbohydrate contents. Owing to the high nutritional value of Cheese helva, the manufacturing technology should be standardized and asceptic packaging techniques should be developed. Currently, the microbiological quality of Cheese helva is not satisfactory because total aerobic mesophilic bacteria and yeast and mold counts are high. Even though a high temperature was applied during the production period, the presence of a high number of microorganisms in the finished product indicates that the raw milk used had a very low hygienic quality or contamination occurred after production was complete.

Acknowledgment

Authors thank the Atatürk University Research Center for funding this project.

Notes

^aMean; ^bStandart error of the mean; ^cstandard deviation; ^dCoefficient of variation; ^eNumber of samples analyzed.

2. Anonymous. Milk Industry; Republic of Turkey, State Planning Organizn. (DPT), Public. No. 2238: Ankara, Turkey, 1990