Detection and Antibiogram Profile of Enterococcus Species from Local Cheese Sample within Ikare and Akungba Akoko, Ondo State Nigeria

Enterococci are part of the normal intestinal flora of humans and animals and are increasingly recognized as significant human pathogens and capable of causing major therapeutic challenges. The aim of this study was to isolate, identify and determine the antimicrobial susceptibility pattern of Enterococcus species in two local cheese sample collected from Akungba and Ikare. The isolation of Enterococcus was carried out using standard culture-based techniques. Antimicrobial susceptibility profile of the Enterococcus species was determined using disk diffusion method. A total number of 93 presumptive Enterococcus species were recovered from forty two different samples over a period of three months. The bacterial count observed on the Bile Aesculin agar ranged from 1.5x104 cfu/ml to 4.6x104 cfu/ml with Akungba sample having the highest bacterial load of 4.6x104 cfu/ml. The Morphology and biochemical characteristics of suspected Enterococcus spp. isolated from the cheese sample revealed Enterococci feacalis as the isolated bacteria. The isolated Enterococcus species were tested against a panel of six antibiotics which include Penicillin G, Vancomycin, Tetracycline, Nitrofurantoin, Ciprofloxacin and Imipenem. It was observed that the isolates were susceptible to tetracycline, imipinem and ciprofloxacin while they are resistant to ciprofloxacin and vancomycin. The prevalence of Enterococci was confirmed with Enterococcus feacium and Enterococcus faecalis as the predominant species isolated in both cheese sample. The ability of Enterococcus species to survive a range of adverse environments allows multiple routes of cross-contamination of Enterococci in causing human disease, including those from food. Overall, greater understanding of the ability of Enterococcus species to survive stresses, of virulence traits and especially of increasing antibiotic resistance, is needed in order to fully appreciate the complexity of Enterococcus species in causing disease.

The effect of partially or totally replacing milk fat by jojoba oil in Domiati cheese production on some nutritional and quality properties

Purpose The purpose of this study is to evaluate the effects of partial or total substitution of milk fat by various levels of jojoba oil on the nutritional, physicochemical and sensory properties of Domiati cheese during cold storage at 6°C for 45 days. Design/methodology/approach The fat percentage of milk used for cheese manufacture was standardized to 4% fat. Five formulas were produced by replacing milk fat with 0%, 25%, 50%, 75% and 100% of jojoba oil, respectively. The physicochemical and sensory properties of cheese samples at 0, 15, 30 and 45th days of cold store were evaluated. Findings No significant differences in moisture, fat, protein and acidity values amongst the control samples and those samples supplemented with different concentrations of jojoba oil. Significant differences (p = 0.05) in total volatile fatty acids were detected amongst experimental cheese samples. The highest values were recorded for control sample containing 100% milk fat, while the lowest values were recorded for cheese sample containing 100% jojoba oil (p = 0.05). Total nitrogen (TN), water-soluble nitrogen (WSN) and trichloroacetic acid soluble nitrogen (TCA-SN) levels of experimental cheeses were nearly same as for control. The results of fatty acids profile showed that jojoba oil has a unique structure of straight monounsaturated alcohols. Significantly (p = 0.05), the highest cholesterol content was recorded for control sample containing 100% milk fat; however, the lowest (p = 0.05) value was recorded for cheese sample containing 100% jojoba oil. At the end time of storage period, control sample manufactured with 100% milk fat had the highest (p = 0.05) values of free fatty acids, peroxide and thiobarbituric acid, while the lowest values were recorded for cheese sample with 100% jojoba oil as a source of fat. The sensory evaluation results demonstrated that blending milk fat with jojoba oil improved the sensory properties of Domiati cheese. Practical implications It is concluded that substitution of 25%, 50%, 75% and 100% of milk fat by equal amounts of jojoba oil enhanced the nutritional and sensory characteristics of Domiati cheese. Originality/value It is concluded that Domiati cheese formulated with substitution of 25%, 50%, 75% and 100% of milk fat by equal amounts of jojoba oil enhanced the nutritional characteristics and improved the sensory properties of produced cheese.

Presence of Aflatoxin M1 in Cube Cheeses Produced in Sivas Region

In this study, the presence and residue levels of aflatoxin M1 (AFM1) were investigated in traditionally produced cube cheeses in Sivas and its region. For this purpose, 90 pieces of cube cheese were used as a material. Cheese samples were collected periodically in November and December 2016 from central sales location and surrounding villages. ELISA technique was applied in aflatoxin analyses. According to the analysis results, AFM1 was detected in total of the cube cheeses. The lowest level of AFM1 was found to be 2.16 ng/kg, the highest was 53.94 ng/kg and the mean was 6.36±0.87 ng/kg. AFM1 level vas determined one cheese sample above to the limit set by European Union.

Importance of the Joint Use of Goat and Cow Milk in the Production of Soft Cheeses

The paper presents the data on the physicochemical composition of cow and goat milk in different seasons of the year, as well as physicochemical data on mixed compositions of cow and goat milk in various proportions for the production of soft cheeses without ripening. The yield of soft cheese samples was calculated for a different combination of cow and goat milk, where a soft cheese sample with a milk raw material ratio of 50/50 and with the addition of extruded chickpea flour had a yield of 20.5%. Thus, it was found that the developed soft cheese formulation from a mixture of milk raw materials with chickpea flour allows the production of an environmentally friendly and biologically complete product.

EVALUATION OF PERCEPTION AND PREFERENCE OF SENSORY ATTRIBUTES FOUND IN FULL-FAT AND LOW-FAT PRATO CHEESE

Prato cheese is the second most commercialized cheese in Brazil and its full-fat variety has very high fat content. The aim of this study was to evaluate the degree of perception and preference of untrained consumers to full-fat and low-fat Prato cheese. For such, eight Prato cheese sample (four full-fat and four low-fat version) weighing 500g each, were submitted to microbiological, physical and sensorial evaluations. The microbiological evaluation consisted of determining the Most Probable Number of coliforms at 35 and 45°C as well as the presence of Salmonella sp. In the physical analyses, we found the values of pH, shear force and performed a color analysis. The sensory analysis was performed from the Preference Test. Both cheese varieties had coliform counts at 35 and 45°C within the thresholds established by current legislation; and there was absence of Salmonella sp. In addition, the physical characteristics were within the expected for the type of cheese evaluated. As for the sensory evaluation, full-fat Prato cheese was preferred for the appearance (52%) and aroma (55%) attributes, however the low-fat variety was better scored for the taste (57%), texture (57%) and overall acceptance (55%). The tasters were able to differentiate the samples, and the low-fat Prato cheese was more widely accepted.

Study of the Chemical and Sensory Properties of a Calcium–Milk Coagulum

The chemical and sensory properties of a calcium–milk coagulum which were prepared from heated skim milk were investigated. The yield of calcium milk coagulum was 18.16%, and this value was higher than the yield of soft cheese which was 10.6%. At zero degree of cold storage, the moisture, total solids, acidity, lactose, proteins and ash% in calcium milk coagulum were 66.6, 33.3, 0.14, 3.7, 26.9 and 1.7 % respectively, While these values in soft cheese were 72,27.9, 0.13, 3.5, 21.8 and 1.4 % respectively.Sensory evolution scores for flavour, holes, bitterness, appearance & colour of calcium milk coagulum at zero degree and after 28 days of storage at 7±1°C were higher than soft cheese, while texture and body scores were less than soft cheese. After 14 days storage at (7±1 °C) the total bacterial count, Coliform count and fungi count of the soft cheese sample was significantly higher than that in calcium milk coagulum.

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The main objectives of the present study were to assess the incidence of E .coli O157:H7 serotype in both raw milk and locally produced soft cheese samples and to evaluate the efficacy of new immunomagnetic separation (IMS) technique for the first time in Iraq for isolation of the same serotype from such products compared to the conventional cultural method .A total of 50 raw milk and soft cheese samples (25 samples of each) were collected randomly at weekly intervals from different retail markets in Baghdad province and its surroundings during the period of six months (from October 2011 March 2012). Each sample was divided into two equal parts where the first part was analyzed for the conventional cultural method and the second part was analyzed for the immunomagnetic separation technique. Five isolates (20%) and seven (28%) were identified as E.coli O157:H7 from the same raw milk samples by both the conventional cultural method and (IMS) technique respectively. Two (8%) and four isolates (16%) were identified as E.coli O157:H7 the same soft cheese samples using the same above methods. The detection limits by the conventional cultural method were 4x103 cfu/ml and 7x102 cfu/gm of raw milk and soft cheese samples respectively, while the detection limits by the (IMS) technique were 1x102 cfu/ml and 12x10 cfu/gm of raw milk and soft cheese sample respectively .Results obtained in this study revealed that the IMS technique has been recognized to be significantly (P<0.05) more efficient in its sensitivity for the detection of low numbers of E.coli O157:H7 than the direct plating conventional method for both raw milk and soft cheese samples.

Selective enumeration of propionibacteria in Emmental-type cheese using Petrifilm™ Aerobic Count plates added to Lithium Glycerol broth

Propionibacteria derived from dairy products are relevant starter cultures for the production of Swiss and Emmental-type cheeses, and the monitoring of which is mandatory for proper quality control. This study aimed to evaluate an alternative procedure to enumerate propionibacteria, in order to develop a reliable and practical methodology to be employed by dairy industries. 2,3,5-triphenyltetrazolium chloride (TTC) inhibitory activity was tested against five reference strains (CIRM 09, 38, 39, 40 and 116); TTC at 0·0025% (w/v) was not inhibitory, with the exception of one strain (CIRM 116). Subsequently, the four TTC-resistant strains, three commercial starter cultures (PS-1, PB-I, and CHOO) and twelve Emmental-type cheese samples were subjected to propionibacteria enumeration using Lithium Glycerol (LG) agar, and Petrifilm™ Aerobic Count (AC) plates added to LG broth (anaerobic incubation at 30 °C for 7 d). Petrifilm™ AC added to LG broth presented high counts than LG agar (P<0·05) for only two reference strains (CIRM 39, and 40) and for all commercial starter cultures. Cheese sample counts obtained by both procedures did not show significant differences (P<0·05). Significant correlation indexes were observed between the counts recorded by both methods (P<0·05). These results demonstrate the reliability of Petrifilm™ AC plates added to LG broth in enumerating selectPropionibacteriumspp., despite some limitations observed for specific commercial starter cultures.