effect of natamycin on keeping quality and organoleptic characters of yoghurt

This study was planned to evaluate the shelf life and the changes occurring in the organoleptic characters of yoghurt supplemented with natamycin during the storage period. Yoghurt samples were prepared and divided into two groups; natamycin was added to the first group at the levels of 10 and 20 mg / kg, while the second group of yoghurt was prepared without natamycin and kept as a control. Yoghurt cups were stored all over the experimental period [35 days] at 4 +/- 1°C. Organoleptic examinations, estimation of pH and titertable acidity as well as enumeration of total moulds and yeasts were done on both treated and control yoghurts. The yoghurts were examined at the 3[rd] and 7[th] days, then weekly till the end of storage period. The treated group of yoghurt showed acceptable degree of organoleptic examination, while yeasts and moulds were not detected till the end of the storage time. On the other hand, control samples of yoghurt showed unacceptable degrees of examination and contamination with moulds and yeasts. Natamycin was proved to be a suitable and effective antifungal agent which increases the shelf life of yoghurt without changing in the normal characters of the products

Incidence of lipolytic and proteolytic fungi in some milk products and their public health significance

A total of sixty random samples of dairy products; 20 of either table butter, cooking butter or kareish cheese; were collected and subjected to mycological and mycotoxicological evaluation. The mean total mould counts were 7.3X 10[1] +/- 6X10[1, 1.8] X10[3] +/- 5.4X 10[2] and 4.1X 10[3] +/- 3.1 X 10[3] cfu m[-1] for table butter, cooking butter and kareish cheese samples respectively. Respective yeast counts were 1 X10[3] +/- 6.1 X 10[2], 3.3 X 10[4] +/- 3 X 10[4] and 1.5 X 10[4] +/- 1.3 X 10[4] cfu ml-1. The highest frequency distribution of all examined samples for mould and yeast counts lies within the range 10 -100 / gm. Aspergillus niger, A. flavus, Geotrichum spp. and Mucor spp. were isolated from the examined samples at varying percentages of 8.3- 41.7. The predominant species of yeasts isolated from table butter, cooking butter and kareish cheese were Candida spp., Rhodotorula spp., and Saccharomyces spp. The isolated moulds and yeasts were evaluated for proteolytic and lipolytic activities on Tributyrin .Aflatoxin M1 was detected in 4 kareish cheese samples in a variable levels ranging from 5 to 35 ppb. The economic and public health significance of isolated moulds and yeasts as well as the sanitary precautions were discussed

Microbiological monitoring of raw milk and yoghurt samples collected from El-Beida city

A total of 80 raw milk and yoghurt samples were randomly collected from different farms and retail markets of different sanitation levels and examined mycologically and bacteriologically at El-Beida city in Libya. Moulds and yeasts were detected in 80 and 50% of raw milk and yoghurtsamples, respectively, with respective mean values of 4.3 X10[5] +/- 2.5X 10[5] and 2.1 X10[4] +/- 1.9 X 10[4]. Aspergillus spp., Cladosporium spp., Mucor spp., Curvularia spp., Penicillium spp., Geotricum spp., Candida spp., Rhodotorula spp., Torulopsis spp. and Saccharomyces spp. could be isolated from both raw milk and yoghurt. Five samples of 40 raw milk once were positive for AFM1 with the mean value of 5 ppb. While in yoghurt samples, AFM1 were detected with mean value of 2.2 ppb among 3 samples of 40. Total counts of aerobic bacteria of examined raw milk and yoghurt samples were 6.1 X 10[5] +/- 5.5 X 10[5] and 6.5 X 10[5] +/- 6.0 X 10[5], respectively. While the mean coliform counts/ ml were 7.0 X10[6] +/- 5.0 X 10[6] and 6.0 X 10[3] +/- 4.0 X 10[3] for raw milk and yoghurt, respectively. Enterobacteriaceae counts /ml of raw milk and yoghurt samples were 2.6 X 10[6] +/- 5.5 x10[5] and 1.5 X 10[4] +/- 1.2 X 10[4]. The economic and public health situation of isolated fungi as well as the control measures for improving the quality of raw milk and milk products were discussed

study on the fungal contamination and prevalence of Aflatoxins and some antibiotic residues in table eggs

A total of fifty random table egg samples were collected from EL-Beida city markets and subjected to mycological examination as well as the detection of residues of aflatoxin and inhibitory substances. The mean total mould and yeast counts of optically clean egg shell and soiled egg shell were 2.7 X 10[4] +/- 2.2 X 10[4] and 3.7 X 10[5] +/- 3.2 X 10[5], respectively. The mean mould and yeast count in egg content were 6.6 X 10[3] +/- 3.1 X 10[3] and 2.5 X 10[4] +/- 1.1 X 10[4], respectively. Aflatoxin residues were detected only in 7 samples and the mean aflatoxin content residues was 0.542 +/- 0.226 ppb. Residues of inhibitory substance were detected in 4% of the examined egg samples