The effect of feeding cows with hay containing variable amounts of herbs on the cheese quality of hard cheese made with mesophilic starter

Milk coming from hay feed cows are being used to produce a range of artisanal cheeses in Europe. Hay-milk contains low number of anaerobic Clostridium spores that can be detrimental to cheeses late in the ripening period. The forage composition has in the literature been correlated with elevated contents of plant derived aroma compounds (terpenes) in cheese. Hard cheese was made using milk from three Danish dairy-farms (A, B and C) where the cows had been feed with three different types of hay (Feed 1, 2 and 3) made from forage containing varying amount of herbs. The cheese was produced over three production periods (I, II and III) with all combinations of dairy-farmer and hay-type. A control cheese was made in all three production periods using normal bulk milk, where the cows were feed primarily with silage. No differences were seen in the content of plant derived aroma compounds in the experimental milk compared to the control milk. The cheeses had similar moisture content and pH development throughout the 12 months ripening period and no differences was seen in the number of starter and non-starter organisms. The control cheeses contained significantly higher cell numbers of Lactobacillus casei within the first 4 weeks of ripening as compared to the experimental cheese. There was a strong correlation between production period and the content of aroma content in the cheeses, but no differences in the aroma content could be related to the type of feed or dairy-farm. High quality cheese could be made without addition of nitrate to inhibit anaerobic spores, from cows feed with hay containing Danish herbs. The experimental milk and cheeses did not contain higher amounts of plant derived aroma compounds; and this could be due a loss of leave material seen during the hay drying step