Effect of somatic cell count in goat milk on yield, sensory quality, and fatty acid profile of semisoft cheese

Abstract

This study investigated the effect of somatic cell count (SCC) in goat milk on yield, free fatty acid (FFA) profile, and sensory quality of semisoft cheese. Sixty Alpine goats without evidence of clinical mastitis were assigned to 3 groups with milk SCC level of <500,000 (low), 500,000 to 1,000,000 (medium), and 1,000,000 to 1,500,000 (high) cells/mL. Thirty kilograms of goat milk with mean SCC levels of 410,000 (low), 770,000 (medium), and 1,250,000 (high) cells/mL was obtained for the manufacture of semisoft cheese for 2 consecutive weeks in 3 lactation stages. The composition of milk was analyzed and cheese yield was recorded on d 1. Cheese samples on d 1, 60, and 120 were analyzed for total sensory scores, flavor, and body and texture by a panel of 3 expert judges and were also analyzed for FFA. Results indicated that milk composition did not change when milk SCC varied from 214,000 to 1,450,000 cells/mL. Milk with higher SCC had a lower standard plate count, whereas coliform count and psychrotrophic bacteria count were not affected. However, milk components (fat, protein, lactose, casein, and total solids) among the 3 groups were similar. As a result, no significant differences in the yield of semisoft goat cheeses were detected. However, total sensory scores and body and texture scores for cheeses made from the high SCC milk were lower than those for cheeses made from the low and medium SCC milks. The difference in milk SCC levels also resulted in diverse changes in cheese texture (hardness, springiness, and so on) and FFA profiles. Individual and total FFA increased significantly during ripening, regardless the SCC levels. It is concluded that SCC in goat milk did not affect the yield of semisoft cheese but did result in inferior sensory quality of aged cheeses.

Clinical Mastitis Gives Off-Flavor and Reduces Quality of Milk in Smallholder Goat Farms

“…This shows that the presence of bacteria does not lead to host reaction to produce reactions to indicate the disease and therefore does not warrant treatment. This agrees with Chen et al, (2010) who found that higher SCC in milk does not lead to high positive cases of presence of bacteria in milk. Park and Humphrey (1986) and Bergonier et al, (2003) have recommended SCC as an acceptable index for mastitis, and this has for many years been used as an index for bovine mastitis.…”

“…In severe infections, lipases and proteinases levels can be very high leading to the development of off-flavour or causing milk instability, and this agrees with Chen et al, (2010) on cheese made from milk with high SCC. Ma et al, (2000) also report similar findings that high SCC milk, had sensory defects of rancidity and bitterness, resulting in low overall quality ratings and were consistent with higher levels of lipolysis and proteolysis.…”

“…This means that the sensory characteristic was slightly liked. Chen et al, (2010) did not find any change in the sensory characteristics in cheese made from milk with high SCC. However, cheese made from milk with high SCC did not affect the yield of semisoft cheese but produced inferior sensory quality of aged cheeses but not affect the composition.…”

Efeitos do estresse térmico na produção de vacas leiteiras: Revisão

“…As principais enzimas envolvidas na deterioração do produto são as proteases e lipases, glicosidases, fosfatases e esterases, embora nem todas essas sejam produzidas por bactérias, fatores ambientais como temperatura, pH e aeração também podem influenciar a síntese e ação dessas enzimas (Chen et al, 2010). Do ponto de vista tecnológico, os microorganismos de maior importância são os que contaminam o leite durante e após a ordenha, essa contaminação é variável, tanto qualitativa quanto quantitativa, em função das condições de higiene existentes (Froeder et al, 1985).…”

Variation in Milk Yield, Contents and Incomes According to Somatic Cell Count in a Large Dairy Goat Population

“…Thus, several authors reported decreased fat content associated to high levels of SCC [7] while others did not find differences in fat content according to SCC level [15,16] or infection status [17][18][19] in small ruminants. In other studies, however, higher fat concentration was found in infected glands than in uninfected ones [20] or related to high levels of SCC [6].…”