The Influence of Nonfat Dry Milk on the Sensory Properties, Viscosity, and Color of Lowfat Milks

The effect of three levels of ascorbic acid on diacetyl and acid production by two mixed-strain cultures was investigated. Each culture was grown in nonfat dry milk reconstituted to 11% total solids with 0.1% added sodium citrate. Ascorbic acid concentrations in the milk were 0, 0.10, and 0.25%. Stimulation of diacetyl production was observed at both concentrations of ascorbic acid. The stimulatory effect of ascorbic acid at both concentrations was approximately the same for each culture. Diacetyl production was initiated earlier in samples containing ascorbic acid. Ascorbic acid did not stimulate acid production.

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Effectiveness of Universal Pre-enrichment Broth for Recovery of Salmonella from Selected Dairy Foods

Journal of AOAC International ◽

10.1093/jaoac/86.4.714 ◽

2003 ◽

Vol 86 (4) ◽

pp. 714-718 ◽

Cited By ~ 4

Author(s):

Thomas S Hammack ◽

R Miguel Amaguaña ◽

Mildred L Johnson ◽

Wallace H Andrews

Keyword(s):

Brilliant Green ◽

The Other ◽

Green Water ◽

Enrichment Broth ◽

Dairy Foods ◽

Whole Milk ◽

Dry Milk ◽

Salmonella Serovars ◽

Nonfat Dry Milk ◽

Positive Results

Abstract The relative efficiencies of 2 Bacteriological Analytical Manual (BAM) pre-enrichments, lactose broth (LAC) and brilliant green water (BGW), were compared with Universal Pre-enrichment (UP) broth for the recovery of individual Salmonella serovars from instant nonfat dry milk (NFDM), dry whole milk (DWM), lactic casein (LC), and liquid whole milk (LWM). BGW was compared with UP broth for the analysis of NFDM and DWM but not with the other 2 matrixes. LAC was compared with UP broth for the analysis of LC and LWM. UP broth was made both from a commercial dehydrated preparation (UPC) and from individual ingredients (UPI). Bulk quantities of the selected dairy foods were inoculated with Salmonella serovars at levels intended to produce fractionally positive results, where at least half of the test portions analyzed, with one of the methods being evaluated, would be shown to be Salmonella-positive. For NFDM, in 6 of 9 experiments, with 2 different Salmonella serovars, BGW was significantly more productive than either UPI or UPC broth (p < 0.05). Salmonella was recovered from 118 of 180 test portions with BGW, from 25 of 180 test portions with UPC, and from 14 of 180 test portions with UPI. For DWM, in 2 of 4 experiments, with 2 different Salmonella serovars, BGW was significantly more productive than either UPI or UPC broth (p < 0.05). Salmonella was recovered from 67 of 80 test portions with BGW, from 36 of 80 test portions with UPC, and from 37 of 80 test portions with UPI. For LWM, in 9 of 9 experiments, with 3 different Salmonella serovars, there were no significant differences among the broths. Salmonella was recovered from 120 of 180 test portions with LAC, from 135 of 180 test portions with UPC, and from 129 of 180 test portions with UPI. For LC, in 5 of 7 experiments, with 2 different Salmonella serovars, both UPI and UPC broth were significantly more productive than LAC (p < 0.05). Salmonella was recovered from 42 of 140 test portions with LAC, from 114 of 140 test portions with UPC, and from 114 of 140 test portions with UPI. In addition, overall results showed that UPC and UPI broths were equivalent for the recovery of Salmonella from the foods tested, without regard to their performance in comparison with either LAC or BGW.

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Survival of Listeria monocytogenes in Simulated Milk Cooling Systems1

Journal of Food Protection ◽

10.4315/0362-028x-51.3.172 ◽

1988 ◽

Vol 51 (3) ◽

pp. 172-175 ◽

Cited By ~ 6

Author(s):

R. PETRAN ◽

E. A. ZOTTOLA

Keyword(s):

Listeria Monocytogenes ◽

Propylene Glycol ◽

Water Systems ◽

Cooling Systems ◽

Dry Milk ◽

Sweet Water ◽

Minimal Media ◽

Nonfat Dry Milk

Survival of Listeria monocytogenes under conditions that might be found in milk cooling systems was studied. Sterile solutions of 0.1 and 0.01% peptone, 0.1 and 0.01% nonfat dry milk (NFDM), 30% propylene glycol, and 30% propylene glycol with 0.01 % NFDM were inoculated with 6000 L. monocytogenes Scott A/ml and were incubated at 4°C. The temperature was increased to 7°C when little growth was observed. At 7°C, populations approached 109 organisms/ml in NFDM and peptone. Growth was greater in the higher concentrations of each, and there was limited survival in the glycol media. Growth in minimal media, 0.01% peptone, 0.01% NFDM, 30% propylene glycol with 0.01% NFDM, and 1 % tryptic soy broth (TSB), was studied. These media were inoculated with 3500 L. monocytogenes Jalisco cheese/ml. At 4°C, more growth was observed in the NFDM than in the peptone, no survival was seen in the glycol media, and the most growth was observed in the TSB. Growth in sterile 10, 20, and 30% propylene glycol solutions (with 0.1 % NFDM) was studied by inoculation with 8800 L. monocytogenes Jalisco cheese/ml and incubation at 4°C. Growth in the 10% solution was observed. However, there was survival in the 20 and 30% solutions with no increase in numbers apparent over the time studied. Presence of L. monocytogenes in milk cooling systems may pose a hazard, especially in sweet water systems that might contain a small amount of milk.

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Comparison of the Dye Binding and Kjeldahl Methods for Protein Analysis of Nonfat Dry Milk and Ice Cream

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/52.1.138 ◽

1969 ◽

Vol 52 (1) ◽

pp. 138-142

Author(s):

J W Sherbon ◽

H A Luke

Keyword(s):

Protein Content ◽

Ice Cream ◽

Protein Analysis ◽

Direct Analysis ◽

Sufficient Accuracy ◽

Coefficients Of Variation ◽

Dry Milk ◽

Dye Binding ◽

Nonfat Dry Milk

Abstract Ten samples of nonfat dry milk and five samples of vanilla ice cream mix were analyzed in quadruplicate in seven laboratories for protein content by the dye binding method. Laboratory and laboratory times sample effects were significant at the 0.5% level but the coefficients of variation were 1% or less. Comparison of average results obtained by dye binding to those obtained by Kjeldahl show the former to have sufficient accuracy. Direct analysis of NFDM was found to give essentially the same results as analysis of the reconstituted product. It is recommended that the dye binding methods for protein in nonfat dry milk and ice cream mix be adopted as official first action.

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