Traditional Fermented Foods of North African Countries: Technology and Food Safety Challenges With Regard to Microbiological Risks

Functional foods in Mediterranean diet: exploring the functional features of vegetable case-studies obtained also by biotechnological approaches

The Mediterranean Diet (MedDiet) is a widely recognized dietary pattern, with its effects largely attributed to "functional foods" which are able to positively influence one or more target functions, improving health and maintaining a state of well-being.In this review, three "case-study" typical of the MedDiet, such as artichokes, capers and table olives are considered as traditional functional vegetables rich in bioactive compounds, mainly polyphenols. The review extensively discusses the antioxidant effects of these molecules, as well as their role in aging prevention and reduction, maintaining human health, and influencing the abundance and composition of intestinal microbiota. Additionally, this review focuses on the fate of the dietary polyphenols along the digestive tract.Among biotechnological strategies, the review explores the role of fermentation process in modifying the biochemical profile, recovery, bioaccessibility and bioavailability of bioactive compounds present in some vegetable foods of MedDiet. Finally, the main challenges in the selection, addition, and maintenance of probiotic strains in traditional food products are also summarized, with a view to develop new probiotic carriers for "functional diets".

Traditional Fermented Dairy Products in Southern Mediterranean Countries: From Tradition to Innovation

Fermented dairy products have been essential elements in the diet of Southern Mediterranean countries for centuries. This review aims to provide an overview of the traditional fermented products in Southern Mediterranean countries, with a focus on fermented dairy products, and to discuss innovative strategies to make improved versions of these traditional products. A large variety of fermented dairy products were reviewed, showing high diversity, depending on the used raw materials, starter cultures, and preparation procedures. Traditionally, dairy products were fermented using spontaneous fermentation, back-slopping, and/or the addition of rennet. Compared with commercial products, traditional products are characterized by peculiar organoleptic features owing to the indigenous microflora. The main limitation of traditional products is preservation as most products were consumed fresh. In addition to drying, brine or oil was used to extend the product shelf life but resulted in high salt/fat products. Several studies suggested alternative ingredients/processing to make revised products with new flavors, improved nutritional quality, and a longer shelf life. There is still plenty of room for more research to obtain a better understanding of the indigenous microflora and on quality improvement and standardization to reach a wider market.

Biochemical and Microbiological Changes Associated with Fermentation of Durum Wheat for Lemzeïet Processing, a Traditional Algerian Fermented Food

In Algeria, “Lemzeïet” is prepared by the natural fermentation of wheat. This study aimed to follow the evolution of microbiological and biochemical properties of Lemzeïet with and without vinegar addition for 3, 6, 9 and 12 months. Lactic acid bacteria (LAB) were identified and the microbial count, as well as pH, acidity, protein, fat, ash and starch contents were determined. Results showed that Lemzeïet samples represented a safe product after the gradual absence of fungi. It also contained a significant load of LAB that were cocci or rods, white or yellow, grouped in chain, pair and tetrad. LAB isolates were mannitol positive, grew between 10 and 45 °C, showed resistance at 63.5 °C and the majority were homo-fermentative. Results showed a significant decrease in pH during fermentation regardless of the vinegar addition. Protein content increased up to 14.90% and 15.50% at the end of fermentation. The fat and starch contents decreased after 12 months of fermentation, regardless of the vinegar addition. Ash content remained high (1.41% and 1.45%) after six months of fermentation with and without vinegar, respectively. The microbiological and the biochemical characteristics of Lemzeïet make it a very interesting raw material in the manufacturing of healthy foods.

Mycotoxins occurrence in milk and cereals in North African countries - a review

North African countries; Algeria, Egypt, Libya, Morocco and Tunisia suffer from mycotoxin contamination. Various studies have indicated the presence of mycotoxins in raw milk and cereals (i.e. wheat, barley, maize and cereal-based products). Aflatoxins (AFs), Aflatoxin M1 (AFM1), Ochratoxin A (OTA), Fumonisin (FB1) and Zearalenone (ZEN)-mycotoxin are the most detected due to climatic change in the region. In this review, we will present the kind of foods and feeds cereals and milk based products contaminated and the level of their contaminated mycotoxin. On the other hand, researchers try to find biologic methods to remove/mitigate mycotoxins in food and feed using bio-products. But the research works concerning legislations and mycotoxin risk assessment still rare. Therefore, it appears necessary to make review on the current status of mycotoxins in North African countries in order to explore data related to contamination of basic food in this region and to highlight the problem to the policy-makers to establish a serious legislation on this matter. On the other hand, to give more information to the worldwide readers about the impact of climate change on the food and feed pollution on mycotoxins in the Mediterranean Sea region.

Foods of the Mediterranean diet: lacto-fermented food, the food pyramid and food combinations

The Mediterranean diet proved to be one of the healthiest diets in the word. It has several beneficial effects and it prevents many non-communicable diseases, such as cancer, cardiovascular diseases, and obesity. Before being a culinary regime, the Mediterranean diet is characterized by specific cultural heritages and traditions, also influencing the lifestyle of the populations. The Mediterranean diet follows the so-called food pyramid, comprising several food combinations. Indeed, it is mainly composed by vegetables, fish and dairy products, while red meat and sweets are poorly consumed. Processed foods are mainly avoided, apart from lacto-fermented ones, the first processed foods consumed by humans. Food fermentation by microorganisms not only improves the functionality of bioactive metabolites, but also increases the shelf life and organoleptic properties of the food. Lactic acid bacteria play a vital role in transforming the food constituents, thereby enhancing their nutritional and functional properties. In addition, these foods introduce beneficial bacteria into gut microbiota, thus maintaining a healthy gut microbiome and corresponding gut-brain axis, thus providing an overall improvement in health and a reduced risk of non-communicable diseases and metabolic disorders. This review will focus on the Mediterranean diet, on its characterising food pyramid and food combinations, and on lacto-fermented foods, one of the components of the Mediterranean diet with the most beneficial effects.

Microbial and Nonvolatile Chemical Diversities of Chinese Dark Teas Are Differed by Latitude and Pile Fermentation

Understanding the microbial and chemical diversities, as well as what affects these diversities, is important for modern manufacturing of traditional fermented foods. In this work, Chinese dark teas (CDTs) that are traditional microbial fermented beverages with relatively high sample diversity were collected. Microbial DNA amplicon sequencing and mass spectrometry-based untargeted metabolomics show that the CDT microbial β diversity, as well as the nonvolatile chemical α and β diversities, is determined by the primary impact factors of geography and manufacturing procedures, in particular, latitude and pile fermentation after blending. A large number of metabolites sharing between CDTs and fungi were discovered by Feature-based Molecular Networking (FBMN) on the Global Natural Products Social Molecular Networking (GNPS) web platform. These molecules, such as prenylated cyclic dipeptides and B-vitamins, are functionally important for nutrition, biofunctions, and flavor. Molecular networking has revealed patterns in metabolite profiles on a chemical family level in addition to individual structures.

Deciphering the Microbiota and Volatile Profiles of Algerian Smen, a Traditional Fermented Butter

In Algeria, Smen is a fermented butter produced in households using empirical methods. Smen fermentation is driven by autochthonous microorganisms; it improves butter shelf-life and yields highly fragrant products used as ingredients in traditional dishes as well as in traditional medicine. The present study is aimed at investigating microbial diversity and dynamics during Algerian Smen fermentation using both culture-dependent and culture-independent approaches, as well as by monitoring volatile organic compound production. To reach this goal, fifteen Smen samples (final products) produced in households from different regions in Algeria were collected and analyzed. In addition, microbial and volatile compound dynamics at the different stages of Smen manufacturing were investigated for one Smen preparation. The results showed that Smen is a microbiologically safe product, as all hygiene and safety criteria were respected. The dominant microorganisms identified by both techniques were LAB and yeasts. Lactococcus spp. and Streptococcus thermophilus were the main bacterial species involved in spontaneous raw milk fermentation preceding butter-making, while lactobacilli and enterococci were the only bacteria found to be viable during Smen maturation. Regarding fungal diversity, yeast species were only recovered from two mature Smen samples by culturing, while different species (e.g., Geotrichum candidum, Moniliella sp.) were identified in all samples by the culture-independent approach. Using microbial analysis of a single batch, many of these were found viable during manufacturing. Concerning the volatile profiles, they were highly diverse and characterized by a high prevalence of short chain fatty acids, methylketones, and esters. Correlation analysis between microbial diversity and volatile profiles showed that several yeast (Moniliella sp., K. marxianus) and LAB (e.g., Lactococcus spp., S. thermophilus) species were strongly correlated with one or more volatile organic compound families, including several ethyl esters and methyl ketones that can be linked to pleasant, sweetly floral, fruity, buttery, and creamy odors. This study clearly identified key microorganisms involved in Smen fermentation and maturation that could be used in the future for better fermentation control and improvement of quality attributes.

A Study of the Antimicrobial Activity of Combined Black Pepper and Cinnamon Essential Oils against Escherichia fergusonii in Traditional African Yoghurt

The antimicrobial activity of the essential oils of black pepper (BPE) and cinnamon bark (CE) extracts against E. fergusonii was assessed in pasteurized full cream milk during and post-fermentation. The milk was fermented with 1% (v/v) of Lactobacillus delbrueckii subspecies bulgaricus (NCIMB 11778) and Streptococcus thermophilus (NCIMB 10387) (approx. 10⁶ cfu/mL each) and incubated and stored at 25 °C for 5 days (144 h) or at 43 °C for 24 h and then stored at 25 °C for 120 h. The milk was spiked with E. fergusonii at the start of fermentation by the lactic acid bacteria (pre-fermentation contamination) for after fermentation (post fermentation contamination). BPE and CE were applied at concentrations based on their minimum inhibitory concentration of 0.5% and 0.25% respectively as follows: 0.5% BPE alone; 0.125% BPE with 0.1875% CE; 0.25% BPE with 0.125% CE; 0.375% BPE with 0.0625% CE; 0.25% CE alone. Results showed that during fermentation at 25 °C, E. fergusonii grew to a similar level (approx. 10⁹ CFU/mL) in control samples and 10⁸ CFU/mL when BPE or CE were added alone. Whereas, in the samples with the combined essential oils, the bacterium grew to 10⁶–10⁷ CFU/mL only. During the milk fermentation at 43 °C, E. fergusonii grew to approx. 10⁹ CFU/mL in samples without treatment. However, it was not detected in samples containing mixed BPE with CE after 8, 10 and 12 h of fermentation. Subsequent storage at 25 °C resulted in undetectable levels of the bacterium in all the samples treated with BPE or CE after 24 h of storage. These results indicated that BPE in combination with CE reduced growth during fermentation and was bactericidal during storage.

Meat and colorectal cancer in Middle Eastern and North African countries: update of literature review

Background

This review discusses the findings from epidemiological studies that have examined the possible role of meat and colorectal cancer (CRC) risk in Middle Eastern and North African (MENA) countries.

Methods

We conducted a literature search in the PubMed, Clinical Trials, Google Scholar, Science Direct, and Cochrane databases for observational studies that investigated the association between meat and CRC risk in adults from the MENA region.

Results

Eleven studies were included in this review. For red meat overall, significant associations were found. Regarding beef meat intake, the study included found controversial results with OR = 0.18 (95% CI 0.03–0.09). A positive association was observed between chicken and CRC risk, at OR = 2.52 (95% CI 1.33–4.77) to OR = 4.00 (95% CI 1.53–10.41) to OR = 15.32 (95% CI 3.28–71.45). A significant association was observed between processed meat intake and CRC risk, OR = 9.08 (95% CI 1.02–80.58).

Conclusion

This is the first literature review which illustrated the association between meat consumption and CRC risk in MENA region. We concluded that these studies included in this review have been controversial and not sufficient to establish a clear relationship between CRC and meat consumption in the MENA region. Further studies are necessary to be carried out in this region, with a larger sample size and submit to rigorous criteria. This review will help researchers to improve the quality of future studies about the association between CRC and nutritional diet in general and meat in particular.

Microbial Safety of Milk Production and Fermented Dairy Products in Africa

In Africa, milk production, processing and consumption are integral part of traditional food supply, with dairy products being a staple component of recommended healthy diets. This review provides an overview of the microbial safety characteristics of milk production and fermented dairy products in Africa. The object is to highlight the main microbial food safety hazards in the dairy chain and to propose appropriate preventive and control measures. Pathogens of public health concern including Mycobacterium bovis, Brucella abortus and Coxiella burnettii, which have largely been eradicated in many developed nations, still persist in the dairy chain in Africa. Factors such as the natural antimicrobial systems in milk and traditional processing technologies, including fermentation, heating and use of antimicrobial additives, that can potentially contribute to microbial safety of milk and dairy products in Africa will be discussed. Practical approaches to controlling safety hazards in the dairy chain in Africa have been proposed. Governmental regulatory bodies need to set the necessary national and regional safety standards, perform inspections and put measures in place to ensure that the standards are met, including strong enforcement programs within smallholder dairy chains. Dairy chain actors would require upgraded knowledge and training in preventive approaches such as good agricultural practices (GAP), hazard analysis and critical control points (HACCP) design and implementation and good hygienic practices (GHPs). Food safety education programs should be incorporated into school curricula, beginning at the basic school levels, to improve food safety cognition among students and promote life-long safe food handling behaviour.

Screening of lactic starter from Tunisian fermented vegetables and application for the improvement of caper (Capparis spinosa) fermentation through an experimental factorial design

Purpose

This study aims at designing a lactic starter for caper fermentation isolated from Tunisian fermented vegetables to improve the process and produce consistent and high-quality product.

Methods

In this study, the lactic starter was isolated by exploring the lactic acid bacteria (LAB) of Tunisian artisanal fermented vegetables. Identification was carried out by partial 16S rRNA gene sequencing. Screening was based on salt tolerance and antagonistic activities against Escherichia coli ATCC 10536 and Enterococcus faecalis ATCC 10541. Caper fermentation was optimized through a full factorial experimental design (23), by exploring three factors: starter inoculum size, NaCl concentration, and acetate content. Differences in pH values, Total aerobic mesophilic bacteria and LAB counts between the beginning and end of fermentation are selected as responses and corresponding regression coefficients were calculated.

Results

The lactic microbiota is mainly represented by Lactobacillus plantarum group. Based on salt tolerance and antimicrobial activity, the strain Lactobacillus plantarum F3 was selected as starter for caper fermentation. The effect of NaCl concentration, acetate content, and inoculum size on acidity, total aerobic mesophilic bacteria count, and LAB count after 1 week and 1 month of caper fermentation was studied. Depending on the fermentation time, either 1 week or 1 month, the initial conditions should comprise 0% acetate, 108 CFU/mL inoculum, and 5% NaCl for 1 week against 5% acetate, 107 CFU/mL inoculum, and 10% NaCl for 1 month lasting caper fermentation. A protocol for caper fermentation was set up ensuring hygienic quality and LAB viability.

Conclusion

Lb. plantarum F3 was selected as lactic starter for caper fermentation, and initial fermentation conditions were optimized through a full factorial design. This work has shown loss in LAB viability after 1 week of fermentation. Based on results obtained, an optimized fermentation protocol was set up. This protocol ensures LAB survival and high hygienic quality of the product.

Consumption of meat, traditional and modern processed meat and colorectal cancer risk among the Moroccan population: A large-scale case-control study

The current study aimed to investigate the relationship between red and white meat subtypes, processed meat (divided into traditional "Khlii, Kaddid" and industrially processed meat) and colorectal cancer (CRC) risk, considering CRC subsites, in Moroccan adults. A case-control study was conducted including 2,906 matched case-control pairs recruited from the five largest university hospitals in Morocco. Dietary data were collected through a validated Food Frequency Questionnaire (FFQ). Multivariable odds ratios (OR) and 95% confidence intervals (CI), for the association of CRC risk with meat consumption (high vs. low intake), were estimated using conditional logistic regression models, adjusted for relevant confounding variables. Overall, consumption of red meat was positively associated with colon cancer and CRC risk (OR = 1.23, 95% CI = 1.05-1.44; OR = 1.14, 95% CI = 1.02-1.27), respectively. In contrast, no significant association was observed between the consumption of red meat and rectal cancer risk (OR = 1.05, 95% = 0.90-1.23). Interestingly, while processed meat from industrial processes was positively associated with colon cancer, rectal cancer and CRC (OR = 1.61, 95% CI = 1.27-2.04; OR = 1.73, 95% CI = 1.34-2.23; OR = 1.67, 95% CI = 1.41-1.98), processed meat prepared using traditional methods was inversely associated with colon cancer and CRC risk (OR = 0.74, 95% CI = 0.57-0.98; OR = 0.77, 95% CI = 0.64-0.93), respectively. Furthermore, positive associations were observed between poultry intake and colon cancer risk among men (OR = 1.27, 95% CI = 1.01-1.59). Our study showed similar associations between the consumption of red meat and CRC risk in Morocco as in developed countries, while inverse associations were found for traditionally processed meat products. This is the first study to investigate the differential effects of traditional vs. westernized processed meat products in a developing country. Other studies are needed to confirm these findings and to understand the physiological pathways underlying these associations.

Teaching Microbiology by Celebrating Traditional Foods and Cultures from Morocco and Perú

According to a report published by the Center for Community College Student Engagement and others, global learning is considered one of the high-impact practices used to increase student engagement and motivation to learn. Engagement and motivation have also been linked to increased learning gains and improvement in the overall learning experience. Furthermore, global learning helps students explore other people's cultures and worldviews, which is an important skill for students to gain in order to compete and adapt to solve the problems of our global society. Here, I discuss two class activities that faculty can adopt to implement global learning in their courses, with the purpose of engaging and motivating students to learn microbiology while celebrating some traditions from Morocco and Perú. Students researched traditional fermented foods and drinks from Perú and Morocco. Then, they answered guided questions to help them link the food items to microbiological concepts learned in class. For example: normal flora and fermentation were learned as students researched the process of making a Peruvian drink called "chicha de jora," which is made from chewed corn that becomes fermented as it mixes with oral bacteria from saliva. While engaging in global learning, students learned some microbiology concepts; they passed the knowledge on to the campus community with poster presentations held during International Education Week. Based on students' feedback and participation, I can conclude that teaching microbiology using global learning was engaging, promoted student learning, and motivated students to learn.

Probiotic Potential and Safety Evaluation of Enterococcus faecalis OB14 and OB15, Isolated From Traditional Tunisian Testouri Cheese and Rigouta, Using Physiological and Genomic Analysis

Lactic acid bacteria (LAB) strains OB14 and OB15 were isolated from traditional Tunisian fermented dairy products, Testouri cheese and Rigouta, respectively. They were identified as Enterococcus faecalis by the MALDI TOF-MS (matrix assisted laser desorption-ionization time of flight mass spectrometry) biotyper system and molecular assays (species-specific PCR). These new isolates were evaluated for probiotic properties, compared to E. faecalis Symbioflor 1 clone DSM 16431, as reference. The bacteria were found to be tolerant to the harsh conditions of the gastrointestinal tract (acidity and bile salt). They were low to moderate biofilm producers, can adhere to Caco-2/TC7 intestinal cells and strengthen the intestinal barrier through the increase of the transepithelial electrical resistance (TER). Susceptibility to ampicillin, vancomycin, gentamicin and erythromycin has been tested using the broth microdilutions method. The results demonstrated that E. faecalis OB14 and OB15 were sensitive to the clinically important ampicillin (MIC = 1 μg/mL) and vancomycin (MIC = 2 μg/mL) antibiotics. However, Whole Genome Sequencing (WGS) showed the presence of tetracycline resistance and cytolysin genes in E. faecalis OB14, and this led to high mortality of Galleria Mellonella larvae in the virulence test. Hierarchical cluster analysis by MALDI TOF-MS biotyper showed that E. faecalis OB15 was closely related to the E. faecalis Symbioflor 1 probiotic strain than to OB14, and this has been confirmed by WGS using the average nucleotide identity (ANI) and Genome-to-Genome Hybridization similarity methods. According to these results, E. faecalis OB15 seems to be reliable for future development as probiotic, in food or feed industry.

Consumption of modern and traditional Moroccan dairy products and colorectal cancer risk: a large case control study

PURPOSE

The main objective of this study is to describe the association between the consumption of either traditional or modern dairy products or calcium intakes and the risk of colorectal cancer (CRC) in the adult Moroccan population.

METHODS

A case-control study was conducted in five Moroccan hospital centers. The study was matched on sex, age (± 5 years) and center. Data were collected using validated food frequency questionnaire (FFQ) taking into account different types of Moroccan dairy products. Conditional logistic regression models were used to assess the association between dairy products consumption, calcium intakes and CRC risk subtypes. In all statistical tests, the significance level was set at 0.05.

RESULTS

Among 1453 cases and 1453 matched controls, 50.7% were women and 49.3% were men. Milk OR^b 0.84, 95% CI 0.74-0.96 and yogurt OR^b 0.74, 95% CI 0.64-0.86 were inversely associated with CRC risk. Similar inverse associations were observed for traditional dairy products namely Lben OR^b 0.77, 95% CI 0.67-0.88, Raib OR^b 0.86, 95% CI 0.76-0.96 and Jben OR^b 0.77, 95% CI 0.67-0.88. The dairy calcium intake was inversely associated to CRC overall OR^b 0.83, 95% CI 0.74-0.93.

CONCLUSIONS

Our study supports previous international evidence and suggests that individuals who have a high intake of either modern or traditional dairy products are at lower risk for CRC. These findings should be further confirmed by longitudinal data and studies investigating potential pathways involved.

El Gueddid, a traditional Algerian dried salted meat: Physicochemical, microbiological characteristics and proteolysis intensity during its manufacturing process and ripening

El Gueddid is a traditional salted and dried meat with high popularity in Algeria. It is used as an ingredient in various dishes. In this study, different samples of El Gueddid were analyzed at different processing times to follow up their microbiological and physicochemical properties. Changes in the protein profile were also demonstrated by electrophoretic study of myofibrillar proteins. Microbiological determinations included the total viable count, coliforms, Staphylococci, lactic acid bacteria, yeasts, and molds, whereas physicochemical properties were characterized by pH, moisture, salt content and water activity. The results showed that microbial profiles were elevated for all the studied micro-organisms. Staphylococci and lactic acid bacteria were the most abundant micro-organisms in the product. Total coliforms were found in low numbers in fresh meat, being eliminated at the post salting stage of process. The physicochemical characteristics showed that the moisture content decreased in the product during the drying period. The pH also decreased during the drying period, then remained almost unchanged during the rest of the ripening period. Moreover, El Gueddid showed low water activity and high salt content. One of the most important changes in the profile of myofibrillar proteins was a reduction in the myosin heavy chain content.

Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review

Foodborne illness resulting from the consumption of contaminated fresh produce is a common phenomenon and has severe effects on human health together with severe economic and social impacts. The implications of foodborne diseases associated with fresh produce have urged research into the numerous ways and mechanisms through which pathogens may gain access to produce, thereby compromising microbiological safety. This review provides a background on the various sources and pathways through which pathogenic bacteria contaminate fresh produce; the survival and proliferation of pathogens on fresh produce while growing and potential methods to reduce microbial contamination before harvest. Some of the established bacterial contamination sources include contaminated manure, irrigation water, soil, livestock/ wildlife, and numerous factors influence the incidence, fate, transport, survival and proliferation of pathogens in the wide variety of sources where they are found. Once pathogenic bacteria have been introduced into the growing environment, they can colonize and persist on fresh produce using a variety of mechanisms. Overall, microbiological hazards are significant; therefore, ways to reduce sources of contamination and a deeper understanding of pathogen survival and growth on fresh produce in the field are required to reduce risk to human health and the associated economic consequences.

Dairy products and colorectal cancer in middle eastern and north African countries: a systematic review

BACKGROUND

This systematic review was conducted to explain the association between dairy products and colorectal cancer (CRC) risk in Middle Eastern and North African countries (MENA).

METHODS

The database consulted were PubMed, Clinical Trials, and Cochrane to extract the relevant studies published till the 31stof December 2016, using inclusion and exclusion criteria according to Prisma Protocol. The characteristics of these studies comprised the consumption of all types of dairy products in relation to CRC risk.

RESULTS

Seven studies were included in this review. For dairy products overall, no significant association was found. Regarding modern dairy products, included studies found controversial results with OR = 9.88 (95% CI: 3.80-24.65) and OR_a = 0.14 (95% CI: 0.02-0.71). A positive association was reported between traditional dairy products and CRC risk, to OR = 18.66 (95% CI: 3.06-113.86) to OR = 24 (95% CI: 1.74-330.82) to ORa = 1.42 (95% CI: 0.62-3.25), p_trend = 0.03. Calcium was inversely associated with the CRC risk with OR_a = 0.08 (95% CI: 0.04-0.17).

CONCLUSION

This is the first systematic review which illustrated the association between dairy consumption and CRC risk in MENA region. The results were inconsistent and not always homogeneous. Further specified studies may be warranted to address the questions about the association between CRC and dairy products in a specific context of MENA region.

The biotechnological potential of subtilisin-like fibrinolytic enzyme from a newly isolated Lactobacillus plantarum KSK-II in blood destaining and antimicrobials

An antimicrobial oxidative- and SDS-stable fibrinolytic alkaline protease designated as KSK-II was produced by Lactobacillus plantarum KSK-II isolated from kishk, a traditional Egyptian food. Maximum enzyme productivity was obtained in medium containing 1% lactose and 0.5% soybean flour as carbon and nitrogen sources, respectively. Purification of enzyme increased its specific activity to 1,140-fold with a recovery of 33% and molecular weight of 43.6 kDa. Enzyme activity was totally lost in the presence of ethylenediaminetetraacetic acid and was restored after addition of Fe(2+) suggesting that KSK-II is a metalloprotease and Fe(2+) acts as cofactor. Enzyme hydrolyzed not only the natural proteins but also synthetic substrates, particularly Suc-Ala-Ala-Pro-Phe-pNA. KSK-II can hydrolyze the Lys-X easier than Arg-X; thus, it was considered as a subtilisin-family protease. Its apparent Km , Vmax , and Kcat were 0.41 mM, 6.4 µmol mg(-1) min(-1) , and 28.0 s(-1) , respectively. KSK-II is industrially important from the perspectives of its maximal activity at 50°C (stable up to 70°C), ability to function at alkaline pH (10.0), stability at broad pH ranges (7.5-12.0) in addition to its stability toward SDS, H2 O2 , organic solvents, and detergents. We emphasize for the first time the potential of fibrinolytic activity for alkaline proteases used in detergents especially in blood destaining.