Works performed on local arab foods

The author has several other research works published in international scientific journals as it could be seen from the list of publications. This proposition was simplified for a rapid review. The investigations of traditional food products had begun by basic studies dealing with the characterization of most non processed foods. This was followed by a laboratory scale preparation of the product is scaled up by a pilot production to make an accurate description of the industrial process. Products are classified by their nature and also by their importance to the consumer.

The high production of olives in Morocco (6.9 % of the world production) and in other Arab countries, the traditional harvest method, and the long storage of fruits at ambient temperatures (20-24°C) before processing may result in a severe loss and a poor quality of fermented olives. The quality control should began from this stage and a lot of factors are acting against this quality which could not be improved in the processing if these factors are not monitored. This was done by the application of The HACCP system for green table olives.

Micro-organisms involved in post-harvest alterations of fruits before fermentation process were studied. This showed that alterations are due first to yeasts and their interactions with Gram negative bacteria (especially Pseudomonas). Most of the isolates belonging to these micro-organisms were cellulolytic and lipolytic.

The natural fermentation of green olives is still applied in Morocco. This traditional procedure is used by the particulars for a low scale production. Little - if nothing - is known on this kind of fermentation in Morocco. Now the high scale production for exportation towards other countries (EEC, USA, Canada) began to adopt the Spanish style fermentation for green olives or Californian style for ripened red olives.

The natural fermentation was studied to determine the fermentation parameters including the microbial species involved in the process. Several strains were isolated from this natural fermentation and which were screened for their fermenting activities on olives to be used in a controlled fermentation in the following step.

Lactic acid bacteria (LAB) including Lactobacillus, Leuconostoc and Pediococcus were isolated from fermenting Moroccan green olives. These were inoculated to brined olives for the improvement of the fermentation. A pilot scale fermentation was carried out. The process was patented and the procedure is available for an industrial application.

Some studies for olives preservation against yeasts and moulds were applied to low scale bulks of green olives (25 kg each) which were treated with garlic (the amounts used were the MICs found in previously "in vitro" studies on the antimicrobial activities of aromatic and medicinal plants. Yeasts and moulds counts showed a net decrease after one month. There was no yeast growth during the following 3 months of storage after the last sample was taken. This may give the evidence that the inhibiting systems used in our experiments could be a successful mean for the preservation of olives against yeasts contamination.

Gaseous deteriorations or bloaters formation in fermented green olives are one of the most known problem in the field of table olive fermentation. These are more and more occurring during the storage of fermented olives in bulk. In some cases these deteriorations are more severe in non controlled conditions storage and may consequently induce large losses of the production.

The gaseous attack is called in Morocco «ropy spoilage» and it would correspond to the «alambrado» in Spain or to the «fish eye» in USA. This attack leads to the floating of the fruits at the upper layer of the brine and would help in the onset of other attacks such as the softening and browning of the fruits.

Various microorganisms could be involved in the gaseous attack of olive fruits such as Gram negative bacteria, yeasts and heterofermentative lactic acid bacteria (Asehraou et al, 2001 ). The control of these attacks were deeply studied in black olives. However, little had been done on the microorganisms involved in the bloater spoilage of fermented green olives during storage. These deteriorations are the most factors that would decrease the eating quality of green table olives and all the people working now on the HACCP of green tables olives should really give much attention to these problems which must be controlled before the fermentation process.

Our results showed that the strains isolated from deteriorated olives fit into five species: Saccharomyces cerevisiae, Pichia anomala, Candida etchellsii, Pichia anomala and Rhodotorula glutinis. Some of the studied isolates from each species showed killer activity on the target strains. Isolates of P. anomala and C. etchelsii were the most active followed by those belonging to S. cerevisiae.

The use of natural inhibitors combined with chemical inhibitors may also decrease the inhibitory concentration of the chemical preservatives. The use of natural plants and or spices in food preservation should be encouraged to lower the toxicity of some foods because of the high concentrations used. Research in this field is still at a premium and more investigations are required to reduce the use of sorbic acid and related chemicals.

These studies were done in laboratory to monitor the process and were also carried out in a high scale production. The process was patented.

Black table olives

Black table olives are prepared by an old process which may consist of drying and salting. The harvested black olives are filled in bags and salted (solid salt is sprinkled on the fruits while filling them in the bags).These bags are empilled one on the other and a heavy material (stone) is deposited on the top bag. The bitter black liquid is driven out under the action of weight and salt. A survey of the most frequent micro-organisms including total plate count, indicator micro-organisms (total and fecal coliforms and enterococci), staphylococci, Salmonella, spore forming bacteria, yeasts and moulds was determined. The physico-chemical characteristics included pH, aw, salt concentration, and the acid degree value of the extracted oil. Results showed a low microbial load except for the yeasts and moulds. The values found for the physico-chemical characteristics including aw pH, salt and polyphenol content would suggest an inhibitory effect on the initial microflora of black olives.

The most representative microbiota was species of moulds which may be associated with food poisonning due to their mycotoxins. The occurrence of toxigenic moulds in black olives processed by the non controlled traditional method is possible. A new process for controlling and accelerating black table olives was studied in our laboratory (unpublished data) by treating olives immediately after harvesting, so the growth of these microorganisms could not reach a high level and secrete the mycotoxins. The most relevant point of the process is the acceleration of salt penetration and drying as well as the inactivation of mould spores. The process is available and can be used with now additional charges for all the olive processing units.

2. Olive oil

Lipid oxidation is a quality-lowering phenomenon that would lead the manufacturers to use some chemicals as antioxidant such as butylated hydroxy toluene (BHT), butylated hydroxy anisole (BHA) and propyl gallate (PG). These compounds are not desirable in foodstuffs because of their chronic toxicity. The substitution of these chemicals by natural preservatives like essential oils or other spices and herbs is preferred by the consumers who are more and more conscious of the safety of food additives or artificial ingredients (colorants, antioxidants, stabilizers, preservatives and flavourings).

The preservative effect of aromatic and medicinal plants was deeply investigated by several authors, but all the studies carried out on aromatic plants were focused on their therapeutic activities mainly the antimicrobial effect of essential oils and various plants were investigated. Other activities and/or properties of aromatic plants in food preservations are now being accurately studied. By the same way we studied also components of aromatic plants for their activity in delaying some chemical deterioration in food systems. This was applied to the antioxidant activities of essential oils from some plants and interesting results were found with lemon essential oil and thyme (and oregano) oils in the prevention of olive oil oxidation.

Prevention of the hydrolytic rancidity in olive oil by the use of essential oils from aromatic plants (Charai et al., 1998)

The preservative effect of aromatic and medicinal plants was deeply investigated by several authors. The antibacterial effect of essential oils from various plants was studied in several investigations (Beylier, 1979; Kivanç and AkgulM 1986; Deans and Svoboda, 1990). More accurately, some plants may have antifungal effect (Bonchird and Flegel, 1984). These materials when used as whole plants (ground) or as extracts by steam distillation, are preferred to synthetic preservatives in the field of food preservation (Faid et al, 1995). Other activities and/or properties in food preservations are now being accurately studied. Some constituents are likely interesting in delaying some chemical deteriorations in food systems. Antioxidant activities of essential oils were studied by Kim et al, 1989; Economous 1991; Zygadlo et al, 1995). Some other synthetic and natural antioxidants or preservatives are described and compared to natural antioxidants from plants by Valenzuela and Nieto (1996). Vitamins C, E and provitamin A were also reported as natural antioxidants by Maestro-Duran and Borja-Padilla (1993).

The use of essential oils as antioxidants in lipids is encouraged by their lipophylic properties and also their use in small amounts. The essential oils from plants are believed to be safer and more healthy than artificial preservatives. Moreover, essential oils are lipophilic compounds, which can be used easily in fats and fat containing foods as natural flavouring agents.

In the present study the antioxidant properties of essential oils from three plants; thyme oregano and lemon on olive oil were investigated.

Essential oils obtained by steam distillation from Moroccan oregano (Origanum compactum, lemon (Citrus limon) and Moroccan thyme (Thymus broussonetti) were analyzed for their chemical composition by gas chromatography. These EO were then used in two concentrations (0.05 % and 0.1 %) in refined olive oil in 6 trials and a control to study the antioxidant properties. The antioxidant activity of the oils was followed up by the determination of the peroxide value and the acid value of the oil over a period of 6 months. Sensory evaluations of the trials were also conducted by a taste panel of 6 assessors for an organoleptic assessments. Results showed a wide variation in the antioxidant activity of the three oils, and also a slight variation between the two concentrations was observed. The highest activity was observed with thyme oil followed by oregano oil, while an organoleptic quality improvement was obtained with the oregano and lemon oils.

1. Beylier M.F. (1979).- «Bacteriostatic activity of some Australian essential oils ».- Perfum. Flav. 4, (2) 23-25.

2. Kivanc K and A. Akgul (1986).- «antibacterial activities of essential oils from turkish species and citrus ».- Flav. Fragr. J. 1, 175-179.

3. Deans S.G Svoboda KP. (1990).-«The antimicrobial properties of marjoram (Origanum majorana L) volatiles oil ».- Flav. Fragr. J. 5, 187-190.

4. Bonchird C. and Flegel T.W. (1984). -«In vitro antifungal activity of eugenol and vanillin against Candida albicans and Cryptococcus neoformans ».- Can J. Microbiol. 28, 1235-1241.

5. Faid, K. Bakhy M. Anchad and A. Tantaoui-Elaraki. (1995).- « Almond paste: Physico-chemical and microbiological characterization and preservation with sorbic acid and cinnamon ».- J. Food Protection. 58 (5) 547-550.

6. Kim S.Y., Kim J.H., Kim S.K. OY M.J. and Jung M.Y. -«Antioxidant activities of selected oriental herbs extracts ».- J. Am. Oil. Chem. Soc. 71, 633-640.

7. Economou K.D., Oreopoulou V. and Thomopoulos C.D. (1991). -«Antioxidant activity of some plant extracts of the family Labiatea ».-J.Am.Oil Chem. Soc. 68 (2) 109-113..

8. Zygadlo J.A. Merino E.F. Guzman C.A. and Ariza-Espinar L. (1995).- «The essential oil of satureja odora and S. parvifolia from Argentina J. Essent. Oil. Res. 5, 549-551.

9. Valenzuela A.B. and Nieto S.K. (1996).-« Synthetic and natural antioxidants ».- Food quality protectors. 47 (3) 186-196

10. Maestro Duran R. and Borja Padilla R. (1993a).-«Actividad antioxidante de las vitaminas Cy Ey de la provitamina».- Grasas y Aceites. 44 (2) 107-111.

11. CHARAI M. FAID M. and CHAOUCH A. 1998. Essential oils from aromatic plants (Thymus broussonetti, Origanum compactum and Citrus sinensis) as natural antioxydants for olive oil. Journal of Essential Oil Research.. 11, 517-521.

The natural fermentation of garlic is well known among vegetables fermentation in Morocco. In this type of fermentation, the microflora responsible for the acidification is naturally present on the fruits themselves. Now the chemical changes and biological changes in garlic during the cold season (sprouting) and the increasing consumption and exportation of this crop were the main objectives of carrying out this work.

Garlic is produced in high amounts in Morocco and need be preserved. The preservation by fermentation against sprouting and spoilage is the most suitable method. This may not require high expenditure for equipments and or the processing.

Inoculated assays were carried out with selected strains of lactic acid bacteria and controlled parameters (pH, Temperature, salt concentration). Results indicated a high quality fermented product which was obtained in 10 days and which was also stored fore one year without any change. The process is being studied deeply (at a pilot scale) to carry out a fermentation directly in cans and a patent is to be issued.

Fermented lemon is usually made and sold with green olives by the same maker. Fermented lemon is used in some culinary preparations in Moroccco because of its agreeable taste and aroma. Large quantities are prepared each year from a local variety of lemon that grows in Morocco. In some cases the fermentation is not well controlled and large proportions are discarded because of spoilage. Our study was focused on the biotechnological aspect of fermented lemon. Strains of lactic acid bacteria were isolated from natural fermenting lemon fruits, purified and characterized. Inoculated assays were then carried out in the laboratory to follow up the physico-chemical and microbiological characteristics of the product. A mixed culture was proposed as a starter for a controlled fermentation. Our method gave a high quality product, which was stored one year with out any change in the organoleptic quality.

Microorganismes associated with the natural fermentation of lemon in Morocco

The traditional natural fermentation is widely employed for many crops such as lemon, pepper, oignon and garlic in a low scale production. In this type of fermentation, the microflora responsible for the acidification is naturally present on the vegetables themselves. Little - if nothing - is known of this kind of natural fermentation of crops mentionned above. The eating quality of the fermented crops is still not objectively defined throughout the world since conditions of fermentation and standards are not defined for these products. Lemon is the second fermented vegetable product (after olives) consumed in Morocco. This product is usually made by the olive processing plants and also exibited in the same way and places olives are sold. Fermented lemons are used in some special culinary preparations and are expensive.

Trials of lemon fermentation were carried out in laboratory in same conditions the fermentation is done by the makers. Bulcks of lemon were washed and brined in desinfected plastic containers. samples were taken during a period of 27 days to follow up the microflora and the physico-chemical propertie of the fruits. Microorganisms related to the natural fermentation of lemon were evaluated in the traditional simulated trials in laboratoiry. These microorganisms included standard plate count, lactic acid bacteria (lactobacilli, Leucocnostoc and Pediococci), Bacillus and coliforms and yeasts. Physico-chemical properties of the brine were also determined in parallel to assess the nature of the microflora that can survive in conditions of high acidity. Results showed that the pH was low and the value reached after 27 days may ensure the preservation of the fruit.

Coliforms decreased significantly to desappear totally in 5 days. Yeasts and lacti acid bacteria showed a very typically growth pattern in three phases. Numbers were also high in the brine during the fermentation period. Lactic acid bacteria were dominated by the species: L. plantarum, L. brevis and Le. mesenteroides and Pediococcus acidilactici. Coliforms decreased rapidly when the lactics reached a high level. Yeasts were observed in high numbers at the end of the fermentation with a slight increase in the pH. The standard plate count was also constant and may have the same pattern as the yeasts counts. yeasts are undesirable microorganisms in the final phase of fermentation.

The present investigation is the first one to show the role of the microorganisms in the fermentation of lemon for a further study of the process to be improved and controlled.

Production of toxigenic metabolites by Penicillium italicum and P.digitatum isolated from citrus fruits. (Faid and Tantaoui-Elaraki, 1989)

Food spoilage by molds is a natural problem occurring more or less frequently depending upon the nature of foods and the environmental conditions. In addition to the economic consequences of mold growth, some fungal species have been shown to produce mycotoxins on foods, which may constitute a potential health hazard for the consumer.

Since the early 1960's, many kinds of food products have been investigated for contamination by toxigenic molds and mycotoxins. However, even though citrus fruits are known to be frequently molded, little data have been published on the potential ability of the molds involved to produce toxic metabolites. Among the fungi that grow on citrus fruits as post-harvest contaminants, P. italicum and P. digitatum are the most common all over the world. They cause, respectively, the so-called blue mold-rot and green mold-rot. The spoilage can occur during commercial shipments as well as in packaging houses and retail markets (1,5).

A P. italicum strain isolated from orange was toxic to ducklings and rats (4). This strain was shown to produce a mycotoxin identifieda 5,6-dihydro-4-methoxy-2H-pyran-2-one (3). Also two different diketopiperazines, known metabolites 0f Aspergillus ustus, were produced in low yield.

by P. italicum in liquid medium and on unsterilized orange peel, but the toxicity of these alkaloids was not specified (6).

The objective of this study is to screen P. italicum and P. digitatum isolated from citrus fruits for toxic metabolites by using biological tests.

Ninety-six mold isolates were obtained from naturally rotten citrus fruits. Among them, forty were identified as Peiticillium italicum and twenty-four as P. digitatum. Twenty-four isolates of the former and twenty of the latter were tested for toxigenesis. They were first grown on Yeast Extract Sucrose (YES) broth for ten d at 22°C. Then, after mycelium removal, the cultures were sterilized by Millipore filtration and the toxicity of the sterile filtrates tested by four different bioassays; i.e. a bacterial test with Bacillus megaterium, a plant test with Lepidium sativum, a test with the brine shrimp Arternia salina and the chick (Gallus domesticus) embryo test. In P. digitatum, 95% of the filtrates were toxic to B. megatenunt, 100% caused strong inhibition of seed gennination in L. sativum, 75% showed acute toxicity to the brine shrimp and 65% were toxic to the chick embryo, while the figures for P. italicum filtrates were about 96%, 71%, 87%, and 42%, respectively. The results observed with the four different tests didn't always correlate.

1. Eckert, J. W. 1978. Post-har0vest diseases of citrus fruits. Outlook on Agriculture. 5:225-232.

2. Faid M.. and Tantaoui-elaraki A. 1989. Production of toxigenic metabolites by Penicillium italicum and P.digitatum isolated from citrus fruits. Journal of Food Protection 12, 194-197.

3. Gorst-Allman, C. P.. C. M. T. P. Maes, P. S. Steyn, and C. J. Rabie. 1982. 5, 6-Dihydro-4-methoxy-2H-pyran-2-one, a new mycotoxin from P.italicum. S. -Afr. Tydskr. Cnem. 35:102-103.

4. Knek, N. P. J. and F. C. Wehner. 1981. Toxicity of P. italicum to laboratory animals. Food Cosmet. Toxicol. 19:311-315.

5. Laville. E. 1971. Evolution des pourritures d'entreposage des agrumes avec l'utilisation de nouveaux fongicides de traitement après récolte. Fruits. 26:301-304.

6. Scott, P. M., B. P. C. Kennedy, J. Harwig, Y-K, Chen. 1974. Formation of Diketopiperazines by P. italicum isolated from oranges. AppI. Microbiol. 28:892-894.

Meat and meat products

Meat as it is known and as it was deeply and widely studied by several investigators through out the world is not well defined. So the carcass preparation and all the phenomena leading to meat are not carried out in the right way. This kind of food may depend on some ethic and religious customs, which could not be changed by science or by technology such as the case of muslim way for slaughtering.

Man was used to preserve perishable foods during high production periods to be used in periods of shortness. The art of preserving meat by salting and sun drying is a practice dating back to several centuries when Muslim countries were used to preserve meat from the sheep sacrificed in "Eid Aladha". Temperatures are high in these countries and refrigeration had not been known yet. So, the only known method to preserve food was salting and drying. The resulting product is called kaddid and it was prepared only when meat is available in large amounts that the family cannot consume within a short period. Spoilage may occur rapidly and the product is discarded.

Food preservation by salting and drying dated back to centuries before the discovery of the microorganisms and their role in foods. Their effect on fresh foods were well established and man was used to prevent food spoilage by salting and, fermenting and/or drying. These are the most used procedure for preserving highly perishable foodstuffs such as meat, fish, cheese etc..

Several meat products have been described with serenity and a lot of them were studied deeply to improve and to modernize their processing. Several fermented meat products are known through out the world such as dried sausages, smoked meats and etc.. However some others were not investigated nor at least described in the literature such as kaddid and Khliaa, which are very common in many countries. But there is no scientific description of their procedures. These products are prepared whenever it was necessary especially when these foods are produced in large amounts. The art of preserving meat by salting and sun drying is a practice dating back to the early history of food technology.

Some meat products, such as sausages, were modernized by milling, inoculating and conditioning. These are known through out the world and are processed in developed countries in huge amounts by a high scale production. Many brands of the same product exist now. Some other products are not known to the industrials nor to the consumers in the developed countries and many of them are now being prepared by traditional procedures. Among these products, kaddid is the oldest meat product known to the African, meadle eastern and southasian countries. This product is prepared from goat, sheep or lamb meat by salting and sun drying until a maximum removal of water, then the obtained product is stored at ambient temperature for at least 1 year.

Biochemical reactions may occur during salting drying and/or during storage leading to the typical characteristic flavour of kaddid. The flavour is qualified as lipolyzed due to the fat hydrolysis and oxidation by lipases either existing in meat or released by the contaminating lipolytic microorganisms. Proteolysis can also occur and lead to some peptides and/or aminoacids, which are involved in characteristics flavour of the product. Kaddid is consumed after cooking and it is used for its flavour rather than for its nutritional quality.

Kaddid is a meat product prepared by the traditional procedure which may consist of the following: All parts of the carcass can be used and meat is deboned except for the thorax. Meat is cut in long pieces to allow salt diffusion and drying. The cuts are sprinkled with a mixture of salt and spices and left for 1 night before drying. Cuts are then exposed to sun by hanging on a string until a maximum drying. The obtained product is called Kaddid and it is stored at ambient temperatures for 1 year.

Our studies carried out on the physico-chemical and microbiological characteristics, showed a very safe and stable food product (Bennani et al, 1995). The product is characterized by a strong flavor due to fat lipolysis and free fatty acids oxidation during drying. Proteolysis may also occur to give some volatile nitrogen compounds improving the flavor of the product.

The traditional procedure of Kaddid making was described by (Bennani et al, 2000) who demonstrated the good preservation of this product by lowering the aw, salting and spice-flavouring (coriander, garlic, pepper). According to the same authors, the product is characterized by a strong flavour due to fat lipolysis and probably free fatty acids oxydation. Proteolysis may also help in flavour development by releasing some amines and/or aminoacids that have a role in the organoleptic quality of foods.

Even if various meat products have been described with serenity and several of them were investigated deeply and even if a lot of fermented meat products are known throughout the world, some others are still not investigated nor described in the literature such as Khliaa. This product is widely consumed in Morocco and in many other African countries.

All parts of the carcass can be used. Meat is deboned and cut in long pieces to allow salt diffusion and drying. The cuts are sprinkled with a mixture of salt and spices and left for 1 night then exposed to sun by hanging on a string until drying. The obtained product called kaddid is then cooked in animal fat until melting. The cooking should be continued until the water is totally eliminated. Fat should be used in proportions more than meat around 60 % fat 40 % meat. The cooked mixture is allowed to cool to room temperature for solidifying and the ready «Khliaa» can be conditioned in containers that can be tightly closed (Figure ).

FRESH MEAT

DEBONING / SLICING

SALTING/SPICING

Salt, Cumin, Garlic

MATURING

8-10 hours

SUN DRYING

6-10 days

KADDID

COOKING

Animal fat

CONDITIONING

KHLIAA

BENNANI L. ZENATI Y. FAID M. and ETTAYEBI M. 1995. Physico- chemical and microbiological characteristics of Kaddid a traditional salted/dried meat product in Morocco. Zeitschrift Für Lebensmittel Unter Suchung und-Forchung. 201: 528-532.BENNANI L. FAID M. and BOUSETA A. 2000. Experimental manufacture of Kaddid a salted dried meat product: Controle of the microorganisms. European Journal of Food Research and Technology. 211, (3) 153- 157.

Meat sources had been developed during the last decades; so the production throughout the world increased in such a way that an overproduction is observed in many developped countries. The scientific progress in the field of animal breeding and feed industries had brought the meat production to a very high level relatively to the other food products. However, meat sources were not well investigated to make a uniform production and distribution throughout the world. Therefore, in the African and Asian countries feed shortness is hard to overcome by the local production or by feed ingredients importation. In these countries local meat sources, which are well adapted, should be developped, if a food strategy could be adopted to solve the problem of proteins shortness in these countries. In fact, camels can be grown in these countries for varying the source of meat and also for taking advantages from the characteritics of this kind of meat. The one humped camel (Camelius dromaderius) is a very interesting species for meat and milk production (Fay et al, 1995).

In Morocco as well as in many other African and Asian countries, the food customs would include camel meat as a very popular meat. People in these countries are used to eat this kind of meat. Moreover, it is preferref in some countries to meat from other species.

In most Arab countries meats are consumed as fresh, and little is known about some local meat products. Our research focused on camel meat for more scientific characterization and for innovating new products from these countries. In the present study microbiological characteristics of camel meat were studied to elucidate more and more its quality.

In the present study samples of camel meat (Camelius dromaderius) were collected from two slaughter houses. All the samples were taken from carcasses after the set of the Rigor-Mortis the same day they are slaughtered. Samples were analysed for their microbiological characteristics which included Plate Count (PC), total and fecal coliforms, enterococci, staphylococci, Salmonella, Clostridium. Temperature and pH were also measured before the analyses. Results showed that the microbial profiles were relatively low for all the microorganisms studied. The average PC was 7.5x10⁶ cfu/g, coliform numbers ranged from less than 10 to 3.6x10² cfu/g. Enterococci reached an average of 4.5x10². Staphylococci were the most abundant microorganisms in the product and ranged from 10⁵ cfu/g to 2.2x10⁷ cfu/g. Salmonella was not detected in any sample. 47 % of the staphylococci isolates were revealed DNAse positive and phosphatase positive. Proteolytics and lipolytics were also present in high numbers in most samples with averages of 1.3x10⁶ and 1.2x10⁶ cfu/g respectively.

Dairy products

Food systems being now processed with modern technology and sophisticated microbiology such as cheeses and fermented dairy products, had been manufactured through centuries by the traditional procedures. The technology of numerous fermented foods was transferred as men moved from one country to another.

Laban

‘Laban’ or ‘leben’ is an Arabic word, which has the same meaning as the Armenian word ‘yoghurt’. Laban is a fermented churned and defatted dairy product obtained from the coagulation of whole raw milk. Laban is widely consumed in Morocco and other countries. Now, it can also be found in some European countries. Even if this product is widely consumed and is also easy to handle, standards do not exist since the process had not been defined yet and a wide variation in its characteristics is usually observed. This variation is due to the species involved in the fermentation and to the conditions the fermentation had been achieved.

The natural fermentation of milk to prepare laban had lead to a variability in the characteristics because the ambient temperature used may vary widely from one country to another. In Asia and the Meadle-East, ambient temperatures are higher than 30°C and in North Africa these would not exceed 20 to 24°C. In the first case thermophilic lactic acid bacteria are the most active in the fermentation and in the second case, strains of lactococci and Leuconostoc are the most responsible.

All the works carried out on laban in Morocco were focused on lactococci because the traditional fermentation would occur under mesophilic temperatures. Thermophilic strains of lactic acid bacteria had been never investigated. Laban can not be neglected as an important dairy product since its consumption is higher than any dairy product. However, no industrial process exist for the product and a lot of similar products are prepared by the traditional procedures which are similar to laban but the microflora had not been characterized for defining the suitable starter cultures to be used in laban manufacture

Laban composition and physico-chemical characteristics have been studied. These studies showed a marked variability among the samples. However, some average values may be given: pH 4.2 to 4.4, acidity 0.75 to 0.82 %, dry matter about 88 g/l. The fat content whose average value is close to 9 g/l, varies from 2 to 18 g/l. The lactose, chlorides and total nitrogen amounts have been determined also, as well as the volatile compounds, i.e. acetaldehyde, ethanol, acetone, diacetyl and acetoin.

On the other hand, the hygienic quality of laban and other products had been investigated. This study showed that Salmonella and Clostridium were absent in 25 ml and 10 ml of laban respectively. The presumably pathogenic staphylococci are either absent or present in low level from 10 to 10⁴ CFU/ml. However, the faecal coliforms reach an average number of 2.85 x 10⁴ CFU/ml, among which 88 % are Escherichia coli and the Enterococci average population is 1.85x10³ CFU/ml.

Thus, the high variability of the physico-chemical characteristics on one hand, and the doubtful hygienic quality of the commercial laban on the other hand, lead us to investigate the possibility of making a product with similar organoleptic properties and better hygienic quality using pasteurized fresh whole milk which would be inoculated with selected lactic acid bacteria belonging to the genera Lactococcus and Leuconostoc. The use of fresh milk in laban making cannot be applied during the season of milk shortness and the use of reconstitued milk seems convenient for the industrials to supply the market with this product. That is the reason why we decided to undertake a new work in order to make laban from reconstitued milk inoculated with strains of Lactococcus.

Smen, a fermented fat made from butter by natural fermentation, remained a family art passed on from one generation to the next. Preparation of smen in the home is considered as a household art. Certainly it does occur, and the traditional procedure is based on age-old experience.

A new process for laban making by the use of thermophylic lactic acid bacteria (Bennani et al., 2000).

Laban or leben is a fermented churned and defated dairy product. Laban is widely consummed in Morocco (Tantaoui et al, 1983a; Boubekri et 1984) and other countries (Abdelmalek et al, 19975; Abo-Elnaga et al, 1977; Baroudi and Collins, 1975) Now, it could be also found in some European countries. Even if this product is widely consummed and is also easy to handle, standards do not exist since the process is not defined yet and a wide variation in the characteritics of the product is observed. This variation is due to the species involved in the fermentation. The natural fermentation of milk to prepare laban had lead to a variability in the characteritics because the ambient temperature used may vary widely from one country to another. In Asia, ambient temperatures are higher than 30°C and in North Africa these would not exced 20 to 24°C. In the first case thermophilic lactic acid bacteria are the most active in the fermentation and in the second case strains of lactococci and Leuconostoc are the most responsible.

All the works carried out on laban in Morocco (Tantaoui et al, 1983a,b) were focused on lactococci because the traditional fermentation would occur under mesophilic temperatures. Thermophilic strains of lactic acid bacteria had been never investigated. Laban can not be neglected as an important dairy product since its consumption is higher than any dairy product. However, no industrial process exist for the product and a lot of similar products are prepared by the traditional procedures which are similar to laban but the microflora had not been characterized for defining the suitable starter cultures to be used in laban manufacture.

In the present work, a process laban making by the use of selected thermophilic lactic acid bacteria strains was investigated.

Up to now all the research works carried out on laban in Morocco have been focused on Lactococcus because the traditional fermentation is usually realized under ambient temperatures which may range between 22 and 28°C in Morocco. Thermophilic lactic acid bacteria had not been investigated yet. Laban is a dairy product widely consummed in North Africa, Asia and some European countries but no industrial process exist for the product. Various similar products are prepared by the traditional or modern procedures. Thermophilic strains of lactic acid bacteria belonging to Streptococcus thermophilus were isolated from natural fermented raw milk. Milk samples from non treated cows and not fed on industrial feeds were incubated at 45°C until curdling. 5% (v/v) of the coagulum were used to inoculate a sterilized milk which was incubated at 45°C until curdling. This operation was repeated 4 times. The last subculture was used to isolate strains of the species S.thermophilus. 57 isolates were collected, characterized and selected for their acidifcation properties of milk at 45°C. The most efficient strains were used in laban preparation at a high scale and the obtained product was compared to the traditional laban and to laban from the retail market by a sensory evaluation. Results indicated that most of the strains were identified as S. thermophilus and that these strains were different from those used in laban from the retail market. The sensory assessments showed that the product was higher in scores than the traditional laban and the products exhibited in the retail market.

1. Abdelmalek Y. (1978). Traditional Egyptian dairy fermentation, in Stauton W.R. and Dasilva E.J. Ed. GIAMV global impacts of Applied Microbiology. UNEP/ UNESCO (Kuala Lumpur, Malaysia) : 198-208

2. Abo-Elnaga I.G., Elaswad M. and Moqi M. 1977. Some chemical and microbiological characteristics of leben. Milchwissenschaft, 32 : 521-524

3. Baroudi A.G. and Collins E.B. 1975. Microorganisms and characteristics of leben. J. Dairy Sci. 59: 200-202

4. Bennani F. Faid M. and Elyachioui M. 2000. Laban processing by the use of naturally selected thermophilic lactic acid bacteria. Microbiology Alimentation Nutrition.

5. Boubekri C., Tantaoui-Elaraki A., Berrada M., and Benkerroum N. 1984. Caractérisation physico-chimique du lben marocain. Le lait, 64 : 436-447

6. Tantaoui-Elaraki A; Berrada M; Elmarrakchi A and Berramou A. 1983a. Etude sur le lben marocain. Le lait. 63 : 230-245

7. Tantaoui-Elaraki A., Berrada M., Elmarrakchi A. and Berramou A. 1983b. Préparation de lben marocain pasteurisé à l’aide de souches bactériennes sélectionnées. Actes Instit. Agro. Vet. 3: 49-58

Benzoate production by lactic acid bacteria in laban.

Benzoates are legally preservatives permitted in many countries and in a variete of food products (Ahlborg, 1977). These preservatives are used for their antimicrobial activity against yeasts, fungi and some bacteria (Chipley, 1993). The use of benzoic acid is not allowed by most countries in many dairy products (Fondu et al., 1984). In Morocco, benzoates are also not allowed to be used in milk products (MAMVA and MSP, 1997). This seems to be explained by the fact that benzoates are more toxic and less effective than sorbates, which are used extensively in dairy products (Branen et al., 1990; Puttemans et al., 1985; Fondu et al., 1984; Sofos and Busta, 1981).

The effect of lben fermentation on benzoate production had not been until now investigated. Milk contains only small amounts of benzoates (Chandan et al., 1977; Hatanaka and Kaneda, 1986), but some fermented dairy products would contain higher levels of benzoates (Sieber et al., 1995). Bertling (1985) reported that the presence of Benzoic acid in milk products is not due to a deliberate addition, but may be the result of unintentional contamination from rennet, veterinary drugs, teat dips, addition of fruit flavorings which contain benzoic acid or bacterial conversion of hippuric acid to benzoic acid. Chandan et al.,(1977) indicated that benzoic acid is produced by lactic acid bacteria used to prepare cultured dairy products. Nishimoto et al., (1969) reported that lactic acid bacteria can convert milk hippuric acid to benzoic acid.

In view of the preservative nature of benzoates as well as their implication in technological and legislative aspects of dairy product additives, the present study was carried out to examine the effects of hippurate addition on benzoate levels during mesophilic fermentation and to evaluate the contribution of benzoate to the shelf-life of lben.

The hippurate effects on benzoate levels during mesophilic fermentation as well as the effects of benzoate on yeast growth in traditional lben were examined. To determine the effect of hippurate on benzoate levels during lben fermentation process, supplied samples and non-supplied samples with hippurate were taken at regular intervals. The production of benzoic acid in lben increased as the levels of added hippurate increased, and this increase followed a linear regression. The conversion of hippuric acid to benzoic acid was between 25-30 and 40-50% at the end of the fermentation process for industrial and traditional lben, respectively.

To determine the effect of benzoate on yeast growth in lben, samples which were supplied with hippurate were fermented and the lben samples prepared were contaminated with a yeast culture and stored in a refrigerator for 7 days. The results showed that all the benzoate levels produced in lben did not stop yeast growth, but did increase the lag phases. These were estimated to 1, 1.5, 2 and 3 days respectively for the benzoic acid levels of 6.8, 14.1, 30.0 and 46.1 ppm.

1. Ahlborg U.G., Dick J., Eriksson H.B. 1977. Data on preservatives in food. Var-Foeda 29 (2) : 41-96.


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