Safety and microbiological quality of frozen dairy desserts sold in Alexandria City

الملخص EN

This study aimed to evaluate the safety and microbiological quality of frozen dairy desserts sold in different shops and supermarkets in Alexandria city.

one hundred samples of frozen dairy desserts ; eighty samples of ice cream of 4 different flavours (vanilla, chocolate, mango and strawberry) 20 of each and 20 samples of frozen yoghurt were collected randomly from Alexandria city.

all samples were subjected to sanitary and microbiological evaluation.

regarding to methylene blue reduction test results revealed that 15(75%), 10(50%), 7(35%) and 2(10%) of examined of ice cream samples (Vanilla, Chocolate, Mango and Strawberry) were qualified as Grade (1); respectively.

while samples with grade (2) were 2(1%), 1(5%), 0(0%) and 1(5%) of examined samples, respectively.

while 2(10%), 2(10%), 6(30%) and 2 (10%) of the four different flavours were Grade (3) with poor quality respectively.

also 1(5%), 7(35%),7(35%) and 15(75%), of samples were grade (4), respectively.

17(85%) frozen yoghurt samples were categorized as Grade (4) and 3(15%) showed grade(3) for methylene blue reduction test; mean values of aerobic mesophilic count (cfu/g) in examined flavoured ice cream (vanilla, chocolate, mango and strawberry) were 1.5x 105 ± 6.1x104, 9.5x106±6.4x105, 4.8x 106 ± 2.4x106 and 5.1x 107 ± 1.8x 107, respectively.

Also, mean values of coliforms count (cfu/g) in vanilla, chocolate, mango, strawberry and frozen yoghurt were 2.5x102 ±7.1x10, 6.6x102±2.5x102, 9.9x103 ± 6.3x103, 4x103 ±1.4x103 and 1.5x102±2.9x1, respectively; while, the respective mean values of Staph.

aureus count (cfu/g) were 1.6x 102 ±7.0x 10, 3.4x102±9.4x102, 1.9x103±1.5x103, 7.4x102±2.9x102 and 3.33x102±1.2x102, respectively.

Finally, mean values of mold count (cfu/g) were 2.2x102 ± 8.4x10, 9.6x102±4.4x102, 3.2x103±1.3x103, 3.7x103±1x 103and 1.3x104±6.4x103in examined vanilla, chocolate, mango, strawberry ice cream samples and frozen yoghurt; respectively.

the present investigation revealed that the communally prepared ice cream products sold at local markets in Alexandria city are unsatisfactory for human consumption.

at retail shops, improper storage temperature and prolonged storage time affects the microbiological quality of ice-cream.

to improve quality of ice cream, Good manufacturing practice (GMP) is mandatory especially at all post pasteurization steps, use of good quality raw materials and automatic machines to minimize handling, adoption of good sanitation practices and application of the HACCP principles in the system along with education of workers on personal hygiene.