Why are most physicochemical parameters not useful in predicting the quality of sheep milk?

Abstract

The impact of microbial growth on the physicochemical parameters of sheep milk was evaluated. The total bacterial counts (TBC) showed a lag phase of 4 h and µ-max of 0.4 log/h. After 8.4 h, the TBC reached the limit established by European Community, pH had a reduction of 0.04, acidity had an increase in 0.04%, and no changes were observed in the ethanol stability. The milk became thermally unstable after 17 h (10 9 cfu/mL), when the pH was 5.71, acidity was 0.36%, and ethanol stability was 21.3%. These results highlighted the extreme stability of sheep milk protein and that acidity may be the best physicochemical parameters to predict the quality of sheep milk.

Innovative dulce de leche made by sheep’s milk with and without the addition of sheep’s milk cream

“…For sheep's milk cream, the average acidity observed was below the maximum value allowed in legislation (0.20% of lactic acid) (Brasil, 1996a). The pH values of sheep raw milk and cream were similar to those found in bovine milk cream (Stephani et al, 2011) and lower than those observed in raw sheep milk (Munieweg et al, 2017;Tribst et al, 2020) and sheep milk ice cream made with skimmed sheep milk added to sheep milk cream (Balthazar et al, 2018b). The cryoscopic index observed in pasteurized sheep milk was below the range recommended by law (-0.530 ° H to -0.555 °H) (Brasil, 2018), the same reported in another study with raw sheep milk (Munieweg et al, 2017), and these differences may be due to the higher milk solids content of sheep as opposed to the legal limits set up for bovine milk (Brasil, 2018).…”

“…The raw materials used in the production of dulce de leche were evaluated and pasteurized sheep milk showed 3.04 ± 0.03% of protein; 3.35 ± 0.05% of fat; 17.64 ± 2.35% of total dry extract; titratable acidity of 0.19 ± 0.01% in lactic acid; pH of 6.66 ± 0.05 and cryoscopic index of -0.518 ± 0.02 ºH. The fat content in pasteurized milk was lower than whole milk of Lacaune sheep, which has average contents above 5.8% (Munieweg et al, 2017;Tribst et al, 2020), due to previous fat removal. Protein values of pasteurized sheep milk were lower than those observed in other studies with raw sheep milk, with averages of 4.8 to 6.0% (Balthazar et al, 2017;Munieweg et al, 2017;Renes et al, 2018), probably due to differences in the processing with removal of components during skimming and heating in pasteurization.…”

“…The protein content of sheep's milk cream was lower than those found in bovine cream marketed in Brazil, with an average of 2.39% (Stephani et al, 2011) and the low efficiency of the skimming equipment may be the reason for this reduced percentage. Pasteurized sheep milk showed acidity above 0.14 to 0.18% of lactic acid defined by legislation (Brasil, 2018), according to other authors (Balthazar et al, 2017;Munieweg et al, 2017;Tribst et al, 2020). For sheep's milk cream, the average acidity observed was below the maximum value allowed in legislation (0.20% of lactic acid) (Brasil, 1996a).…”

Development and characterization of two novel formulations of Labneh cheese of sheep’s milk

“…The processing of sheep milk products requires care to avoid the multiplication of unwanted microorganisms, due to the high nutritional value, high water content and pH close to the neutrality (Balthazar et al, 2019a;Munieweg et al, 2017;Tribst et al, 2020), for this reason it is important to monitor the total aerobic mesophilic, an indicator group that may include pathogenic and deteriorating microorganisms (Forsythe, 2013;Tribst et al, 2020). The total aerobic mesophilic count in Labneh of buffalo milk was 7.34 log CFU/g at 15 days of storage (Salem et al, 2013).…”

Mascarpone cheese from sheep's milk - a new option for the consumer

“…Ovine milk contains higher levels of solids than bovine milk and sheep milk produced in Brazil shows fat and protein levels varying from 5.9 to 8.8% and 4.0 to 6.0%, respectively (Balthazar et al, 2017;Barros et al, 2020;Munieweg et al, 2017;Nespolo and Brandelli, 2012;Tribst et al, 2020). This ensures greater industrial performance in cheese production, especially in the case of mascarpone, since it is produced from cream.…”