scholarly journals Evaluation of microbial quality and safety of selected dairy products with special focus on toxigenic genes of Bacillus cereus

Mljekarstvo ◽  
2021 ◽  
pp. 257-268
Author(s):  
A.H. Adam ◽  
Keyword(s):  
Bacillus Cereus ◽  
Dairy Products ◽  
Coliform Bacteria ◽  
Contamination Level ◽  
Special Focus ◽  
Microbiological Analysis ◽  
Plant Origin ◽  
Milk Products ◽  
Soft Cheese ◽  
Significant Difference

Although dairy products play a significant role in human nutrition, they may cause a risk to the consumers. This study intends to determine the microbial contamination level in selected milk products concerning Bacillus cereus enterotoxigenic genes. Three hundred plant-origin flavoured cheese, flavoured yogurt, flavoured drinking yogurt, kareish (skim milk cheese), soft cheese, and Ras (Romy) cheese (50 samples for each) were randomly collected from retail markets at different districts in El Fayoum Governorate, Egypt. The microbiological analysis and the molecular identification of Bacillus cereus by multiplex PCR were applied and revealed potential risks associated with consumption of the tested milk products (white soft, Ras, and kareish cheeses). In all analysed cheeses (white soft, Ras and kareish) a high contamination level with coagulase positive staphylococci (20.0 %, 22.0 % and 20.0 %) and coliform bacteria (76.0, 86.0, and 88.0 %) was detected. The highest percent (78.0 %) of fungi was found in kareish cheese samples. Bacillus licheniformis was the most aerobic spore forming bacteria detected in kareish cheese (23.7 %) and flavoured drinking yogurt (17.0 %) samples. The highest prevalence (8.0%) of Bacillus cereus was recorded in the flavoured drinking yogurt and white soft cheese samples. The (nhe) was the most detected gene (100.0 %) in all of the examined samples. There was a significant difference (p<0.05) between nhe and ces genes in all investigated samples except in flavoured drinking yogurt samples. Salmonella sp., Escherichia coli and Pseudomonas aeruginosa were not detected. This survey is one of the very few surveys that describe the safety and quality status of plant-origin flavoured cheeses and flavoured drinking yogurt, particularly in Egypt.

COMPARISON OF MICROBIOLOGICAL QUALITY OF MILK PRODUCTS FROM ORGANIC AND CONVENTIONAL PRODUCTION

2018 ◽  
Vol XX (6) ◽  
pp. 147-153
Author(s):  
Anita Kukułowicz
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Dairy Product ◽  
Microbiological Quality ◽  
Organic Production ◽  
Microbiological Analysis ◽  
Milk Products ◽  
Significant Difference ◽  
Conventional Production

The aim of the research was to compare the microbiological quality of dairy products derived from organic and conventional farming. The test material consisted of milk and milk products (natural yoghurt, cream, curd cheese, rennet ripening cheese, milk). Investigated products were subjected to microbiological analysis and marked for the number of Enterococcus sp., Staphylococcus aureus, yeast and moulds, Escherichia coli as well as to state the presence of Salmonella sp. in them. All samples were free of Salmonella sp. Escherichia coli occurred in 2 samples of curd cheese from organic production. Products derived from organic and conventional production didn’t differ in the average number of microorganisms depending on the type of dairy product, with the exception of ripening rennet cheese, which showed a significant difference in the amount of Staphylococcus aureus.

scholarly journals EXTEND THE SHELF LIFE AND IMPROVING SENSORY PROPERTIES OF WHITE SOFT CHEESE BY ADDING CELERY …..LEAVES

2019 ◽  
Vol 50 (6) ◽  
Author(s):  
Awda & et al.
Keyword(s):  
Antimicrobial Activity ◽  
Moisture Content ◽  
Ash Content ◽  
Coliform Bacteria ◽  
Apium Graveolens ◽  
Soft Cheese ◽  
White Cheese ◽  
Significant Difference ◽  
Total Bacteria ◽  
Control Samples

This study  was aime to investigate the effect of addition different concentration of celery leaves  to white soft cheese ,Treated cheese between 2018-2019, ,The finely Celery (Apium graveolens)   leaves  were  adding  to crude white  cheese  after texturizing in three leveles  included (A,B,C)  in addition of control   antimicrobial activity of celery treated  cheese  against total account bacteria and coliform bacteria was estimated  during (0, 5, 10, 15, 20) days. The results were shown that the higher concentration of celery in treated cheese, had a lower concentration of  protein, lipid and ash content ( 16.81,15.13 and 4.30% respectively, but  it had a higher moisture content 59.50%.also the total bacteria  counts  were decreasing significantly (0.05 P)with accumulative of cheese during astorage periods, it was reached to 1.3x105 , 9.5x103, 9x103, 7.62x103 , 1.05x104     (cfu/g)  respectively comparing with control samples,the number of  coliform bacterial in celery treated cheese,  at  concentrations 15%  was achieved significant difference comparing with  other samples ( 8x103,10.2x104, 9.7x104 , 8.9x105, 9.5x107( log cfu/g )  respectively.

scholarly journals Bacteria from the Bacillus cereus group as contaminants in requeijão curd cheeses and especialidade láctea tipo requeijão

2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Jamile de Oliveira Hachiya ◽  
Gabriel Augusto Marques Rossi ◽  
Higor Oliveira Silva ◽  
Rafael Akira Sato ◽  
Ana Maria Centola Vidal ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Shelf Life ◽  
Dairy Products ◽  
Bacterial Group ◽  
Bacillus Cereus Group ◽  
Significant Difference ◽  
The Impact

ABSTRACT: This study aimed to evaluate the occurrence of Bacillus cereus group in requeijões and especialidades lácteas tipo requeijão (regular and light) and to verify if there is differences in relation to this occurrence among different categories of these products. A set of 14 (35%) lots was contaminated with this bacterial group from the 40 lots with low counts (maximum 3.1 × 10 CFU/g), and no significant difference regarding counts or presence/absence were observed among the categories of the products. It can be concluded that contamination by B. cereus group in these products is unable to consist in risk to consumers, regarding adequate refrigeration during selling. This study was the first one to report this bacteria group for these dairy products and highlights the needs of further investigations to evaluate the impact of its spoilage during shelf life.

scholarly journals The Role of Probiotic Bacteria on Microbiological and Acceptability of Sudanese White Soft Cheese

2021 ◽  
Vol 04 (05) ◽  
Author(s):  
Alwaleed Ibrahim Dafalla ◽  
Keyword(s):  
Pathogenic Bacteria ◽  
Storage Period ◽  
Bifidobacterium Bifidum ◽  
Probiotic Bacteria ◽  
Coliform Bacteria ◽  
Microbiological Analysis ◽  
Overall Acceptability ◽  
Soft Cheese ◽  
Microbial Analysis

The objectives of this investigation is to study the effect of three types of probiotic bacteria (Lactobacilus rhamnosus, Lactobacillus casei, Bifidobacterium bifidum) on the microbiological and acceptability of Sudanese white soft cheese during storage period 0, 15, 30, 45 and 60 days. Microbiological analysis revealed that, the highest count of probiotic bacteria (87x108cfu/g) was obtained by sample containing L.rhamnosus and the lowest (39x106 cfu/g) by sample containing B.bifidum, while the sample containing L.casei ranked in intermediate position. Storage period affected the total probiotic bacteria count, the highest count at 2 weeks for L.casei and B.bfidum and after 4 weeks for L.rhamnosus, while the lowest at the end. The microbial analysis did not detect any pathogenic bacteria (coliform bacteria, salmonella and staphylococcus aureus) or yeast and molds. The sensory evaluation quality revealed that the cheese containing L.rhamnosus gave the best appearance, texture, flavour and overall acceptability, followed by L.casei and B.bifidum compared with the control samples. The storage period significantly (p≤0.05) affected the acceptability of the cheese, where the highest score was obtained at day 30 and the lowest at the beginning of the storage. The study recommends further studies and tests to improve the quality of the Sudanese white soft cheese treated by probiotic bacteria.

scholarly journals Evaluation of the microbiological quality of some dairy products

2018 ◽  
Vol 11 (1) ◽  
pp. 27-44
Author(s):  
É. Laslo ◽  
É. György
Keyword(s):  
Dairy Products ◽  
Microbiological Quality ◽  
Cottage Cheese ◽  
Contamination Level ◽  
Processed Cheese ◽  
Public Market ◽  
Soft Cheese ◽  
Fresh Cheese ◽  
Favourable Environment

Abstract Owing to their nutrient composition, dairy products ensure a favourable environment for different microorganisms. In our study, we investigated the microbiological quality of 22 different commercially available dairy products obtained from local stores and the open-air public market. Among the studied samples four were salty type soft cheese, two were fresh cheese, one was soft cheese (Mascarpone), one was feta-like cheese (Telemea), five were varieties of processed cheese, one was mozzarella, one was a semi-hard cheese, one was smoked cheese, five were cottage cheese, and one was a dairy spread. Samples were evaluated for the presence of Pseudomonas sp., total coliforms, Escherichia coli, Salmonella sp., Staphylococcus aureus, Bacillus cereus and Clostridium perfringens, yeast, and microscopic fungi. Contamination level of the evaluated dairy products varied widely. Among the dairy samples one salty soft cheese, a processed cheese and one cottage cheese were the most contaminated, while low microbiological load was detected in the other samples.

scholarly journals Detection of emetic toxin (ces) gene and antimicrobial susceptibility of Bacillus cereus isolates from Iranian traditional dairy products

2020 ◽  
Author(s):  
Mahdieh Heydarzadeh ◽  
Afshin Javadi ◽  
Mehdi Ghiami Rad
Keyword(s):  
Antimicrobial Resistance ◽  
Bacillus Cereus ◽  
Foodborne Pathogens ◽  
Dairy Products ◽  
Ice Cream ◽  
Raw Milk ◽  
Resistance Pattern ◽  
Contamination Level ◽  
Traditional Dairy Products ◽  
Contamination Levels

Abstract Background Bacillus cereus is known as one of the major foodborne pathogens that often associated with the contamination of raw milk and dairy products. The aim of this study was to isolate the emetic toxin-producing Bacillus cereus (B. cereus) in unpasteurized traditional dairy products. Also, the antimicrobial resistance pattern was investigated in the isolates. Methods For this purpose, 150 samples of unpasteurized ice cream, cheese, doogh, curd and butter (prepared by traditional method) were randomly selected from the market from March 2019 to July 2020. Samples were evaluated for the presence of emetic toxin-producing B. cereus using culture and PCR method. Results Sixteen of 150 (10.66%) samples were contaminated with B. cereus. This pathogen was isolated from one (3.33%) sample of ice cream, 9 (30%) of doogh, 6 (20%) of curd in the mean contamination levels of 2.0 ± 0.0 and 4.4 ± 0.6, respectively. B. cereus was not isolated from cheese and butter samples. The contamination level of curd to this bacterium was significantly higher than other products (p < 0.05). PCR results showed that 14 (78.5%) of 16 isolates contained the ces gene. The results of the antibiogram test showed that B. cereus isolates were resistant to penicillin, cefazolin and co-trimoxazole (trimethoprim-sulfamethoxazole), semi-sensitive to vancomycin and erythromycin, and sensitive to gentamicin, ciprofloxacin and clindamycin. Also, 31.25% of isolates were resistant to six antibiotics simultaneously. Conclusion The findings of present study showed that traditional unpasteurized dairy products could provide a great potential for intoxication by antimicrobial-resistance and emetic toxin-producing strains of B. cereus.

scholarly journals Effect of starter culture fermentation of milk on the production, sensory attributes and storage of Wara (a Nigerian unripened soft cheese)

2021 ◽  
Vol 22 (3) ◽  
pp. 107-117
Author(s):  
W.G. Ajibola ◽  
S.M. Adeyemo ◽  
B.O. Omafuvbe
Keyword(s):  
Shelf Life ◽  
Lactobacillus Plantarum ◽  
Lactobacillus Acidophilus ◽  
Starter Culture ◽  
Sensory Attributes ◽  
Cow Milk ◽  
Microbiological Analysis ◽  
Cell Counts ◽  
Soft Cheese ◽  
Significant Difference

This study investigated the effect of Lactobacillus plantarum and Lactobacillus acidophilus isolated from wara, a Nigerian unripened soft cheese, on the production of starter-mediated type with improved quality and longer shelf-life. Fresh cow milk was pasteurized and inoculated with  standardized cells of Lactobacillus plantarum and o Lactobacillus acidophilus (singly and in combination) and incubated at 30 C for 24 h to ferment. The fermented (acidified) milk was then used to produce wara using juice extract of Calotropis procera as rennet. Viable cell counts and physicochemical properties were estimated in the fermenting milk, while organoleptic attributes of traditional and starter-mediated wara were determined following standard procedures. The wara samples were stored at 30±2 °C for 6 days during which samples were obtained daily for physicochemical and microbiological analysis. Overall, physicochemical analysis of the fermenting milk samples showed a gradual drop in pH, increase in total titratable acidity and diacetyl level with accompanied increase in viable count. Organoleptically, there was no significant difference (p> 0.05) between the traditional and some of the starter-mediated wara. During storage, the starter mediated wara had the lowest bacteria count and extended shelf-life. Keywords: Wara, Starter culture, Shelf life, Sensory attributes, Fermentation. 

scholarly journals Evaluation of dahi collected from Netrokona district in Bangladesh

2016 ◽  
Vol 45 (2) ◽  
pp. 60-65
Author(s):  
S Ahmed ◽  
MN Islam ◽  
MH Rashid ◽  
MM Islam ◽  
AKM Masum
Keyword(s):  
Research Work ◽  
Bacterial Count ◽  
Coliform Bacteria ◽  
Total Bacterial Count ◽  
Microbiological Analysis ◽  
Significant Difference ◽  
Different Types ◽  
Dairy Science ◽  
Type Sample

The aim of the present research work was to make a comparative study between the quality of dahi available in Netrokona district of Bangladesh and dahi prepared in the laboratory by following standard manufacturing process. For this purpose dahi (control) was prepared in Dairy Technology Laboratory of the Department of dairy science, Bangladesh Agricultural University, Mymensingh. The Laboratory made dahi was designated as A type dahi. On the other hand four different types of dahi sample were collected from four different sweetmeat shop of Netrokona district. One sample was taken from each sweetmeat shop and three replications were made for each sample. Source of dahi samples were Khan Mistanno Vandar; Krisno Mistanno Vandar; Shankar Mistanno Vandar; Misti Mokh, These samples were designated as B, C, D and E respectively. Parameters used to monitor the quality of dahi were physical, chemical and microbiological. Collected data were compiled and statistically analyzed by using one way analysis of varience (ANOVA) test by using MSTAT statistical package. It was observed that total physical score for A, B, C, D and E type of samples were 93.21±0.51, 86.98,±0.63, 78.99±0.62, 76.47±0.25 and 83.89±0.44 respectively. Statistical analysis showed that total score for A type (Lab. made) dahi was significantly (p >0.01) higher than the total score of other dahi samples. Chemical analysis showed that average fat, protein, total solids, solids not fat, ash and lactose content of A type dahi were significantly ( p > 0.01) higher than that of the B, C. D and E type dahi samples collected from different shops of Netrokona district. Microbiological analysis showed that total bacterial count, yeast and mould count of B, C, D and E type dahi samples were also significantly (p > 0.01) higher than A type dahi which was prepared in the laboratory. Although total number of coliform bacteria was lower in A type sample but there was no significant difference within different dahi samples. Judging from the results of all parameters studied it was observed that dahi samples collected from Netrokona district was inferior to dahi prepared in the Laboratory. It was also observed that quality of other four dahi samples of Netrokona was nearly similar.Bang. J. Anim. Sci. 2016. 45 (2): 60-65

scholarly journals An outbreak of Bacillus cereus toxin-mediated emetic and diarrhoeal syndromes at a restaurant in Canberra, Australia 2018

2019 ◽  
Vol 43 ◽  
Author(s):  
Callum E Thirkell ◽  
Timothy S Sloan-Gardner ◽  
Marlena C Kaczmarek ◽  
Ben Polkinghorne
Keyword(s):  
Bacillus Cereus ◽  
Structured Interview ◽  
Microbiological Analysis ◽  
Food History ◽  
Health Food ◽  
Public Health Action ◽  
Laboratory Evidence ◽  
Hygiene Practices ◽  
Symptom Profile ◽  
Significant Difference

A cluster of gastrointestinal illness was detected following receipt of a complaint of becoming ill after a multi-course dinner at a restaurant in Canberra, Australian Capital Territory (ACT), Australia. The complaint led to an investigation by ACT Health. Food samples retained by the restaurant for microbiological analysis returned an unsatisfactory level of Bacillus cereus in beef (19,000 colony forming units/gram [cfu/g]) and a satisfactory level in arancini (50 cfu/g). These positive samples underwent whole genome sequencing and genes encoding diarrhoeal toxins were detected with no laboratory evidence of the emetic toxin. No stool specimens were collected. A cohort study was undertaken and 80% (33/41) of patrons took part in a structured interview. There was no significant difference in age or sex between those ill and not ill. Due to universal exposure most foods were unable to be statistically analysed and no significant results were found from the food history. The ill cohort diverged into two distinct groups based on incubation period and symptoms suggesting this outbreak involved B. cereus intoxication with both diarrhoeal and potentially emetic toxins. Some hygiene practices during food preparation were noted to be inadequate and heating and cooling procedures were unverified when questioned. A combination of the incubation periods and symptom profile, food laboratory evidence, and genomic sequencing of the B. cereus diarrhoeal gene suggest a probable aetiology of B. cereus intoxication. Public health action included the restaurant rectifying hygiene practices and documenting heating/cooling procedures.

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