کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5767584 1628388 2017 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Growth potential of Listeria monocytogenes in soft, semi-soft and semi-hard artisanal cheeses after post-processing contamination in deli retail establishments
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش تغذیه
پیش نمایش صفحه اول مقاله
Growth potential of Listeria monocytogenes in soft, semi-soft and semi-hard artisanal cheeses after post-processing contamination in deli retail establishments
چکیده انگلیسی


- Post-contamination of cheeses at retail results in high numbers of Listeria.
- There is a high inter- and intrabatch variability in growth potential.
- Absence of L. monocytogenes in 25 g (n = 5) at the time of production is needed.
- Better growth of Listeria is obtained on cheese slicing surface than cheese rind.
- Soft cheeses are at higher risk toward listeriosis than semi-hard cheeses.

Opportunities for post-processing contamination of cheese may occur in deli retail establishments, either during the further cheese ripening (at maximum 14 °C), during storage and display in the refrigeration cabinet (at maximum 7 °C) or during slicing. A L. monocytogenes post-processing contamination was simulated by inoculation either on the cheese slicing surface or the cheese rind of three soft cheeses (one white-molded raw cow's milk cheese, one pasteurized cow's milk cheese with spicy herbs, one washed rind pasteurized cow and sheep's milk cheese) and two semi-hard cheeses (one smear-ripened raw cow's milk cheese and one natural-ripened raw cow's milk cheese). L. monocytogenes challenge testing was performed on 3 batches of each cheese to assess the growth potential of L. monocytogenes after 14 days storage at either 7 or 14 °C. Substantial growth of L. monocytogenes (>0.5 log CFU/g) was obtained in 79.2% of all individual challenge tests (n = 178) that were performed although huge variation in growth potential was noted among the different cheese types and storage conditions. The growth potential on soft cheeses stored at 7 °C ranged from 1.8 to 4.0 log units and from 3.6 to 5.5 log units upon storage at 14 °C, whilst on semi-hard cheese, this was in general lower, and ranged from 0.1 to 1.4 log units at 7 °C and from 0.0 to 3.0 log units at 14 °C. Overall, increased outgrowth of L. monocytogenes was noted when inoculation was performed on the cheese slicing surface compared to the cheese rind. Thus if occasional post-processing contamination takes place during storage or handling of the cheese, L. monocytogenes has the potential to grow to elevated numbers throughout a reasonably expected storage period of up to 14 days notwithstanding the presence of high numbers of indigenous lactic acid bacteria in these cheeses. Also for a defined cheese type both a considerable inter-batch and intra-batch variability was sometimes noted from the replicate testing, indicating no consistent behavior of L. monocytogenes in these fermented dairy products. As such it is recommended that appropriate hygienic measures are taken to prevent post-processing contamination. Noting the growth potential, absence of L. monocytogenes in 25 g of cheese using a multiple sample subunit approach (n = 5) at the time of production is important to ensure compliance to EU legislation 2073/2005.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Food Control - Volume 76, June 2017, Pages 13-23
نویسندگان
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