ORIGINAL RESEARCH Survival of micro-organisms and organic acid profile of probiotic Cheddar cheese from buffalo milk during accelerated ripening MIAN A MURTAZA, 1 * NUZHAT HUMA, 2 MUHAMMAD A SHABBIR, 2 MIAN S MURTAZA 3 and MUHAMMAD ANEES-UR-REHMAN 1 1 Institute of Food Science and Nutrition, University of Sargodha, Sargodha 40100, 2 National Institute of Food Science and Technology, University of Agriculture, Faisalabad 38040, and 3 Department of Food Science and Technology, Muhammad Nawaz Shareef University of Agriculture, Multan 60000, Pakistan The study aimed to assess the impact of ripening at elevated temperatures on the survival of probi- otic micro-organisms and production of organic acids in Cheddar cheese. Cheese was manufac- tured from buffalo milk using lactococci starters along with different probiotic bacteria (Lactobacillus acidophilus LA-5, Bifidobacterium bifidum Bb-11 and Bifidobacterium longum BB536) as adjunct cultures. The cheeses were ripened at 4–6 °C or 12–14 °C for 180 days and examined for composition, organic acids and microbial survival. The production of organic acids was accelerated at 12–14 °C when compared to normal ripening temperatures. The probiotic bacte- ria increased production of lactic and acetic acids, compared to cheese made with lactococci alone. The survival of the mesophilic starters was significantly (P < 0.05) reduced in all the cheese sam- ples ripened at the higher temperature. However, the probiotic bacteria remained viable (>7.0 log 10 cfu/g) throughout the 180 days of ripening, irrespective of temperature. It was concluded that Cheddar containing additional probiotic cultures can effectively be ripened at elevated temperatures without any adverse effects. Keywords Cheddar cheese, Buffalo milk, Cheese ripening, Probiotic adjuncts, Organic acids. INTRODUCTION The decline in consumers’ interest in common dairy products has led food processors to develop more functional foods (Ahmad et al. 2015). Nowadays, there is considerable interest in the ingestion of probiotic bacteria through food, particularly milk products (Isa and Razavi 2017). Probiotic bacteria are ‘live micro-organ- isms that, when administered in adequate amounts, confer a health benefit on the host’ (FAO 2001; Hill et al. 2014). The incorporation of probiotic bacteria in foods results in func- tional products with numerous beneficial effects. It is important to ensure that the probiotic strains are present and alive in sufficient num- bers in food products to ensure the ultimate health benefits (Liu et al. 2015) because, to have any effect, the probiotic bacteria need to be alive when reaching the intestine (Guerin et al. 2017). The ingestion of about 1 9 10 6 to 1 9 10 7 cfu of viable probiotic bacteria per gram is required to effectively deliver benefits (Ong and Shah 2009). Common health benefits of probiotic foods are the relief of symptoms of lactose intolerance, anticarcinogenic effects, management of diarrhoea and type 2 diabetes, decline in blood cholesterol and support of the immune system (Wang et al. 2010a; Sharma and Devi 2014; Lollo et al. 2015a). Economic globalisation has enabled probiotic bacteria of various origins to be accessible in all areas of the world market, producing probiotic food products with characteristic properties (Dantas et al. 2016). Dairy desserts are appro- priate carriers of functional components such as prebiotic fibres and probiotic bacteria (Buriti *Author for correspondence. E-mails: mian.anjum@uos.edu.pk; anjum_ft@yahoo.com © 2017 Society of Dairy Technology Vol 70 International Journal of Dairy Technology 1 doi: 10.1111/1471-0307.12406