Inhibitory effect of Limosilactobacillus reuteri and nisin against Listeria monocytogenes in pasteurised Halloumi cheese
Amin N Olaimat, Murad A Al‐Holy, Ala Qatatsheh, Hamzah Al‐Qadiri, Fajer Al‐Aittan, Jumana M Faris, Mahmoud AbughoushBackground
Halloumi cheese (HC) is a hard or semihard cheese that is characterised by having high water activity ( a w ), moderate pH and bountiful nutrients, making it a suitable environment for foodborne pathogens to proliferate. As ready‐to‐eat foods, cheeses should be free from Listeria monocytogenes and other pathogens.
Aim
The probiotic bacteria Limosilactobacillus reuteri and nisin were tested for their potential to inhibit L. monocytogenes in HC (10.0% brine) under various temperatures (4, 10 and 24°C).
Methods
Limosilactobacillus reuteri and L. monocytogenes were inoculated into HC at an initial level of ca. 10 6 –10 7 cfu/ml and 10 5 –10 6 cfu/g of brine, respectively. Nisin was added to the brine solution at the levels of 500, 1000 and 1500 IU/ml. The inhibitory effect of L. reuteri and nisin on L. monocytogenes was monitored for a 30‐d storage. Total mesophilic bacterial count (TBC) and yeast and mould counts were determined. The a w , salt content and pH changes were measured.
Major Findings
Limosilactobacillus reuteri
grew in
Scientific or Industrial Implications
The study demonstrated that L. reuteri , as a probiotic, could considerably pose an antimicrobial potency against L. monocytogenes . Nisin was unequivocally effective in inhibiting the growth of L. monocytogenes in HC .