Microbiological Safety of Blue and Cheddar Cheeses Containing Naturally Modified Milk Fat

1995 ◽  
Vol 58 (2) ◽  
pp. 132-138 ◽  
Author(s):  
SHAWN M. SCHAFFER ◽  
SITA R. TATINI ◽  
ROBERT J. BAER

Milk containing naturally modified fat was obtained by feeding lactating dairy cows a Control diet and two experimental diets containing either extruded soybeans or sunflower seeds. Milk from cows fed the experimental diets contained higher levels of both long chain (C18-C18:2) and unsaturated fatty acids than the milk from cows fed the Control diet. Each milk was pasteurized, standardized to 3.6% milk fat, and inoculated with Listeria monocytogenes (strains Scott A and V7), Salmonella typhimurium and Salmonella senftenberg, before manufacturing into Blue or stirred-curd Cheddar cheeses. Populations of L. monocytogenes and Salmonella spp. were monitored during manufacture and aging using Oxford and Xylose Lysine Desoxycholate agars, respectively. During the manufacture of Blue and Cheddar cheese, and during the aging of Blue cheese, behavior of Salmonella spp. and L. monocytogenes in the experimental cheese was similar to the Control cheese. During aging of Cheddar cheese, the rate and extent of decline of Salmonella spp. and L. monocytogenes varied among the cheeses. Declines correlated with the accumulation of specific fatty acids, namely C12, C14, C18:1 and C18:2. These fatty acids were also found to be inhibitory to S. typhimurium and L. monocytogenes when incorporated into tryptic soy agar plates at 37°C. Therefore, the natural fat modification of Blue and Cheddar cheeses enhanced the safety of these cheeses.

1997 ◽  
Vol 64 (2) ◽  
pp. 181-195 ◽  
Author(s):  
FRANCIS ENJALBERT ◽  
MARIE CLAUDE NICOT ◽  
CORINE BAYOURTHE ◽  
MICHELE VERNAY ◽  
RAYMOND MONCOULON

Dairy cows fitted with ruminal, duodenal and ileal cannulas were utilized to investigate the effects of feeding with Ca soaps (CaS) of palm fatty acids (FA) and rapeseed FA. Diets compared were control diet based on maize silage and concentrate, and two diets with 40 g CaS of palm oil FA or rapeseed oil FA/kg diet, replacing part of the concentrates of the control diet. Total digestibilities of dry matter, fibre and fat, and ruminal fermentation were not significantly altered by giving CaS; the extent of ruminal biohydrogenation of total unsaturated C18 FA was significantly reduced by both CaS diets. Apparent intestinal digestibility of FA was not different among diets, although the amount of FA absorbed with the CaS diets was twice that with the control diet. No difference among diets was observed for milk production, or fat and protein contents. Giving CaS diets decreased the proportions of 4[ratio ]0 to 14[ratio ]0 FA in milk fat, and increased cis-18[ratio ]1n−9, compared with control diet. The rapeseed diet lowered the content of 16[ratio ]0, and increased the contents of 18[ratio ]0 and trans-18[ratio ]1n−7. CaS diets did not result in a marked increase of polyunsaturated FA content in milk fat. Butter from cows fed on the CaS diets contained more liquid fat at 6 and 14°C than butter from the cows fed on the control diet. Incorporating CaS, particularly those from rapeseed, in dairy cows' diets increased C18 FA in milk and improved butter spreadability.


2020 ◽  
Vol 42 ◽  
pp. e47200
Author(s):  
Laila Khaled Hassan ◽  
Ahmed Behdal Shazly ◽  
Abd El-Kader Mahmoud Kholif ◽  
Ahmed Farouk Sayed ◽  
Mahmoud Abd El-Aziz

Produce and compare soft cheese with potential benefits of human health from Egyptian buffalo's and cow's milk was studied. Eight Egyptian lactating buffalos and cows were fed a total mixed ration supplemented with either 0% oil (CD), 2% flaxseed oil (DFO), 2% soybean oil (DSO), or 2% of their mixture (1:1, DFSO) according to a double 4 x 4 Latin Square design. Milk yield was similar between buffalo's diets but was higher in cows fed a DFO, DSO or DFSO resulting in 11.15, 8.21% or 8.97% increases compared with the control diet, respectively. Milk composition was not significantly affected in both buffalos and cows fed diets. The DFO, DSO or DFSO displayed decreased short-chain fatty acids, especially DSO and DFSO (3.73 and 3.33%, respectively) when compared to CD for buffalo milk (6.32%). The DSO and DFSO were  more effective for increasing unsaturated fatty acids followed by the DFSO in buffalo's milk fat (42.31 and 41.90 %), whereas DFO and DFSO were more effective in cow's milk fat (39.67 and 39.84%), respectively. DFO, DSO or DFSO had no significant effect on the yield, composition and sensory properties of resultant soft cheese compared to the CD for both lactating cows and buffalos. During storage, a diet rich in unsaturated fatty acids enhances protein proteolysis and antioxidant activity of soft cheese during storage compared to the CD especially for soft cheese produced from buffalo's milk.


2002 ◽  
Vol 2002 ◽  
pp. 181-181
Author(s):  
A.L. Lock ◽  
P.C. Garnsworthy

The Δ9 -desaturase system (steroyl-CoA desaturase) involves the addition of a cis double bond between carbons 9 and 10 of fatty acids. The conversion of stearic acid (C18:0) to oleic acid (cis-9 C18:1) is the predominant precursor:product of this enzyme system; conversion of saturated fatty acids (SFA) to mono-unsaturated fatty acids (MUFA) is important in determining the fluidity of milk. In previous studies (Lock & Garnsworthy 2001), we have shown that more than 50% of the oleic acid occurring in milk is produced in the mammary gland via Δ9 -desaturase. We also found that the conversion of trans-11 C18:1 to cis-9, trans-11 conjugated linoleic acid (CLA) accounted for ~80% of milk fat CLA. Increasing the activity of Δ9 -desaturase offers the opportunity of increasing the MUFA content of milk, especially oleic acid, while decreasing its SFA content, as well as increasing the CLA content of milk. Lock & Garnsworthy, (2001) also reported that there were significant differences between individual cows with regard to milk fat CLA content. In an earlier study (Lock & Garnsworthy, 2000) we found that the CLA content of milk varied throughout the year, with highest values occurring when cows received fresh pasture. In view of the significant contribution of Δ9 -desaturase to the CLA and MUFA content of milk, the objective of the work reported here was to investigate individual animal and dietary variation in Δ9 -desaturase activity in the mammary gland of lactating dairy cows.


2006 ◽  
Vol 86 (4) ◽  
pp. 547-556 ◽  
Author(s):  
R. H. Zhang ◽  
A. F. Mustafa ◽  
X. Zhao

Sixteen lactating Dorset ewes were used in a completely randomized design to determine the effects of oilseed supplementation on milk yield and composition, blood metabolites, cheese yield and composition and fatty acid profile of milk and cheese. Four iso-nitrogenous diets were formulated: a control diet (CT) with no oilseed supplementation, a flaxseed supplemented diet (FS), a sunflower seed supplemented diet (SF), and a canola seed supplemented diet (CS). Oilseed-supplemented diets were formulated to contain 7% fatty acids. Feeding oilseeds had no effect on dry matter intake. Milk yield was similar for ewes fed CT, FS and SF and was higher (P < 0.05) than that of ewes fed CS. Ewes fed oilseed-supplemented diets produced milk with higher (P < 0.05) protein and total solid percentages than those fed CT. However, milk fat percentage was only higher (P < 0.05) in the milk of ewes fed FS and SF relative to those fed CT. Actual cheese yield was higher (P < 0.05) from milk of ewes fed oilseed-supplemented diets relative to those fed CT. However, cheese composition was not affected by dietary treatments. Plasma concentrations of fatty acids and cholesterol were increased (P < 0.05) while plasma concentration of β-hydroxybutyrate (βHBA) was decreased (P < 0.05) by oilseed supplementation. However, plasma concentrations of glucose and mammary extraction rate of plasma metabolites were not influenced by oilseed feeding. Oilseed supplementation increased (P < 0.05) concentrations of unsaturated fatty acids in milk fat. The order of increase was SF > FS > CS. Feeding SF, FS and CS increased (P < 0.05) conjugated linoleic acid (CLA) concentration in milk by 83.5, 39.2 and 16.5%, respectively. Concentration of linolenic acid in milk was only increased (P < 0.05) by feeding FS. Changes in milk fatty acid profiles were reflected in the cheese. Key words: Ewes, oilseeds, milk, cheese, fatty acids


2008 ◽  
Vol 53 (No. 5) ◽  
pp. 219-226 ◽  
Author(s):  
Z.L. Liu ◽  
D.P. Yang ◽  
P. Chen ◽  
S.B. Lin ◽  
X.Y. Jiang ◽  
...  

The aim of this experiment was to investigate the effect of supplementing the basal diet with oilseeds on blood parameters and composition of milk fatty acids, especially conjugated linoleic acid (CLA). Forty-eight lactating Holstein cows in early lactation were used in a randomized block design. The cows in each group were fed the control basal diet (the control diet) or diets containing roasted soybean (RSB), roasted linseed (RLS), roasted sunflower seed (RSS), hulled roasted peanut (HRP) and roasted cottonseed (RCS), respectively. Milk yield and dry matter intake (DMI) were not significantly different. Milk fat percentage and yield decreased (<I>P</I> < 0.05) in RLS, RSS and RCS diets compared with the control. Feeding various oilseeds had no effect on plasma parameters, but it tended to increase concentrations of <I>trans</I> C18:1 and C18:2 in plasma. In milk fat, the concentrations of short and medium fatty acids decreased while C<sub>18</sub> unsaturated fatty acids increased when the cows were fed oilseed diets. <I>Ci</I>s-9, <I>trans </I> -11 CLA content increased (<I>P</I> < 0.01) in the milk fat of cows fed oilseeds. RSB treatment produced the highest (<I>P</I> < 0.01) content of<I> cis</I>-9, <I>trans </I> -11 CLA, which was a 60% increase compared with the control. The results indicate that the diets supplemented with oilseeds improve the content of C<sub>18</sub> unsaturated fatty acids and CLA in milk fat, and soybeans seem to be the optimal source to improve the nutritive value of milk compared with other oilseeds.


2000 ◽  
Vol 83 (11) ◽  
pp. 2620-2628 ◽  
Author(s):  
D.C. Donovan ◽  
D.J. Schingoethe ◽  
R.J. Baer ◽  
J. Ryali ◽  
A.R. Hippen ◽  
...  

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3122
Author(s):  
Jalil Ghassemi Nejad ◽  
Bae-Hun Lee ◽  
Ji-Yung Kim ◽  
Kyung-Il Sung ◽  
Hong-Gu Lee

The effects of grazing lactating cows in mountainous areas for 12 and 24 h compared with the confined indoor system were evaluated by examining the overall milk fatty acid and cortisol. Twenty-one dairy cows were allocated to three treatment groups: (1) control (confined management system in a free-stall barn; TMR based), (2) grazing for 12 h (12hG; TMR plus grazing pasture), and (3) grazing for 24 h (24hG; pasture-based feeding system). Dry matter intake was higher in the control and 12hG groups than in the 24hG group. The yields of total milk and the 3.5% fat-corrected milk were the lowest in the 24hG group. Milk fat was the highest in the 24hG group and higher in 12hG compared with the control group. Milk protein and lactose levels were the highest in the 12hG group. The highest somatic cell count was observed in the 24hG group. The saturated fatty acid levels were higher in the control group compared with the 12hG and 24hG groups. There was no difference in overall mono-unsaturated fatty acids between 12hG and 24hG groups. Poly-unsaturated fatty acids were higher in the 12hG group compared with the control and 24hG groups. There was no difference in omega-6 (ω-6) fatty acids among the groups, and omega-3 fatty acids were higher in the 12hG group than in the control group. Milk cortisol was the highest in the 24hG group and higher in the control group compared with the 12hG group. Taken together, grazing for 12 h is advisable for farms that have access to mountainous areas to improve the milk fatty acid profile and decrease the stress levels in high-yielding Holstein lactating cows.


2021 ◽  
Vol 51 (2) ◽  
pp. 262-270
Author(s):  
I.M. Boldea ◽  
C. Dragomir ◽  
M.A. Gras ◽  
M. Ropotă

The objective of this research was to assess the effects of including oil-rich feedstuffs in diets for lactating goats on the fatty acid (FA) profile of their milk. Thirty-six Murciano-Granadina goats were randomly assigned to three treatment groups, namely a control diet (CTRL), a diet based on whole rapeseed (RS), and a diet based on pumpkin seed cake (PSC). The diets were composed of 1 kg hay (70 % Italian ryegrass, 30% alfalfa) and 1.24 kg concentrate, and were formulated to be isoenergetic and isonitrogenous. Milk yield and its contents of protein, fat and lactose did not differ significantly among the groups. However, including oil-rich feeds in the diet altered the fatty acid profile of the milk significantly, decreasing its saturated fatty acid (SFA) content and increasing its content of unsaturated fatty acids (UFAs). Effects on polyunsaturated fatty acids (PUFAs), conjugated linoleic acid (CLA), and the n-6 to n-3 ratio depended on the source of dietary lipids. The PSC augmented diet increased the relative amount of PUFAs and fatty acid methyl esters (FAME) in milk (+25 %) significantly In comparison with CTRL, whereas the RS diet produced a limited and statistically insignificant increase (+7.5%). The concentration of CLA was higher in milk from does fed the PSC diet, whereas the n-6 to n-3 ratio was lower in milk from does fed RS. These preliminary results form the basis for developing premium dairy products that are enriched in fatty acids that are more favourable for human health.


2014 ◽  
Vol 63 (244) ◽  
pp. 563-573 ◽  
Author(s):  
J.E. Freitas Júnior ◽  
F.P. Rennó ◽  
J.R. Gandra ◽  
L.N. Rennó ◽  
A.C. Rego ◽  
...  

2011 ◽  
Vol 91 (1) ◽  
pp. 147-167 ◽  
Author(s):  
Riazuddin Mohammed ◽  
Reza Khorasani ◽  
Laksiri Goonewardene ◽  
John Kramer ◽  
John Kennelly

Mohammed, R., Khorasani, R. G., Goonewardene, L. A., Kramer, J. K. G. and Kennelly, J. J. 2011. Persistency of milk trans-18:1 isomers and rumenic acid in Holstein cows over a full lactation. Can. J. Anim. Sci. 91: 147–167. A long-term lactation study was undertaken to determine whether the previously reported short-term persistency in vaccenic acid [VA; trans(t)11-18:1] and rumenic acid (RA) could be maintained. To test this hypothesis, 24 Holstein cows were allotted to two experimental diets (control and test) from 2 wk before calving until they were 270 d in milk (DIM). The test diet was similar to the control diet, but supplemented with sunflower seed (11.2% diet DM), fish oil (0.5%) and monensin (22 mg/kg DM) by replacing an equivalent amount of barley grain. The forage: concentrate ratio was 50:50 (DM basis) with 35% barley silage and 15% alfalfa hay. Milk was sampled every fortnight from the start of lactation until cows were 270 DIM. Data obtained were averaged into three equal periods of 90 d each, representing three stages of lactation (SOL): early-lactation (EL), mid-lactation (ML) and late-lactation (LL). Dry matter intakes were not different between treatments with greater intakes observed during ML than during EL or LL. Milk yield was not different between treatments and decreased with increasing DIM. Milk fat content and yield showed interaction between treatment and SOL with lower values observed for the test diet than control diet during EL and ML. De novo synthesized fatty acids (4:0–15:0), 16:0–16:1 and preformed fatty acids (17:0 and above) showed interaction between treatment and SOL with the former two being greater for control diet than test diet and the latter greater for the test diet than control diet within each SOL. Milk t10-18:1 (% fatty acid methyl esters, FAME) was greater for the test diet compared with control diet (4.38 vs. 1.32) and was greater during ML (3.79) than during EL (2.38) or LL (2.38). Milk VA and RA showed interactions between treatment and SOL with greater values observed for the test diet than the control diet within each SOL. When analyzed by treatment, milk VA was not different across SOL for both diets. Milk RA was not different across SOL for the test diet, but was different for the control diet; it was lower during EL than during ML. Step-wise regression analysis revealed that the variability in milk RA for the control diet (P<0.01; R2=0.97) was determined by VA (70%) and RA/VA (27%); and for the test diet (P<0.01; R2=0.987) by VA (88.7%), RA/VA (5%) and t10-18:1 (3.8%). Desaturase index based on RA/VA showed an interaction between treatment and SOL; it was greater for the control diet than the test diet within each SOL. Overall findings revealed that the differences in milk t10- and VA across SOL reflected possible differences in starch and PUFA intakes, respectively. Differences in milk RA across SOL for the control diet could be attributed to possible differences in mammary desaturase activity based on differences in RA/VA.


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