Zabadi was manufactured using reconstituted skim milk powder prepared with different ratios of water and sweet whey and the organoleptic properties and chemical composition of the milks were measured. Sweet whey could be used successfully to replace up to 50% of the water added for reconstitution, whilst with 75 or 100% whey a sweet off flavour appeared. However, these higher levels could be used for fruit flavoured zabadi, and about 40–60% less sucrose could be used because of the additional glucose + galactose contributed by the whey.

The keeping quality of properly refrigerated pasteurized milk and cream is primarily determined by post-pasteurization contamination by Gram-negative psychrotrophic bacteria (Phillips et al. 1981; Schröder et al. 1982). Reliable and rapid methods of assessing the levels of contamination by these organisms are therefore of commercial interest.

The protein composition in goat milk undergoes changes throughout the different lactation periods, displaying distinct characteristics that are influenced by the dynamic nature of protein composition and concentration during the transition from colostrum secretion to mature milk. To evaluate the dynamics of whey proteins of Saanen goats during the colostral phase and the first month of lactation, 110 milk samples from 11 healthy mammary halves of seven Saanen goats were selected through a clinical evaluation. Whey was obtained by rennet coagulation of the mammary secretion. The biuret method determined total protein concentration, and their fractions were identified by 12% dodecyl sulfate-polyacrylamide gel electrophoresis. Maximum concentrations of all protein fractions were observed in the first 12 h of lactation, reducing throughout the study. Modification of the protein predominance was also observed. The transition from colostrum secretion to milk occurred 5 or 7 d postpartum.

Levels of Cu and Fe in fresh milk and in bulk pasteurized milk were measured. The endogenous levels varied during the lactation period. The level of Cu in bulk pasteurized milk was greater than the endogenous level, suggesting some contamination. This apparent Cu contamination was greater in winter than in summer. No similar contamination was observed with Fe. The levels of Cu and Fe in butter manufactured each month and in retail butter were measured. Higher levels of Cu were detected in ripened cream butter produced in winter compared to that produced in summer. No similar trend was evident for Fe in ripened cream butter. Very low levels of Cu, Fe and lipid oxidation were detected in Irish sweet cream butter and consequently Cu and Fe contamination and resultant oxidation are not a problem in this product.

In order to compare the old and the modified methods of the methyleneblue reduction test, 185 samples of raw milk were examined. We followed Wilson's method absolutely, but included two tubes in each test, one of which was inverted and the other not.

The results obtained and their interpretation agreed with the theoretical expectations given in our previous paper, and briefly outlined at the beginning of the present paper.

It is found that the deviations in the reduction time, corresponding to a given initial number of cells, are smaller by the modified than by the old method, and that the average time of reduction is shorter.

The smaller variation in the reduction time corresponding to a given number of cells at the beginning of the test is due probably to a more uniform distribution of the bacteria in the milk following the inversion of the tube. Wilson's suggestion that the shortening of the reduction time in the modified method is due to the stimulation of bacterial growth proves to be entirely correct. We obtained the average coefficients of multiplication in the old method of 0·660, and in the modified of 0·885.

Our results confirm on the whole the positive value of the modification of the methylene-blue reduction test as suggested and worked out by Wilson.

Lyphan paper M 25 can be used for pH measurements in milk and whey in the pK range 5·4—6·6. As a rule the error does not exceed 0·1 pH.

In very acid milk and whey (pH < 5·4) lyphan paper of the L series may be used. Generally the deviation does not exceed -0·2 pH. In alkaline milk and whey lyphan paper cannot be used.

In milk and whey from cows infected with mastitis M 25 may be used unless the pH exceeds 7.

The technique of paper chromatography of bacterial extracts has been successfully applied to the routine examination of lactobacilli from cheese. One hundred and nine strains isolated on selective media have been grouped by their chromatogram patterns, and selected strains from these groups have been shown to have biochemical characteristics giving relationships which are in agreement with the chromatogram groupings. The results indicate that the technique can be used routinely for the rapid identification of strains of lactobacilli.

The C.O.B. test has been carried out at 15 min. intervals on raw milk samples stored at 20°C. to examine worker and replicate variability. Within experimental limitations, the differences between workers were not significant (P>0·05) and, in general, good agreement was found between the five replicates examined for each milk sample, coefficients of variation less than 4·0%. The change from absence to presence of a precipitate generally occurred with successive tests, but there were indications that the times to increased intensity of clotting differed with samples.

Captain H. Barkworth was responsible for the plan and design of these experiments which were carried out by members of his staff at Shardlow.

The goal of the present study was to determine the best quarter milk flow for teat cup detachment depending on lactational stage and milking interval to optimize the milking process in automatic milking systems (AMS). Milking characteristics and post-milking teat condition were recorded in an AMS with all actions from teat cleaning to post-milking teat dipping occurring in the same teat cup and liner (GEA DairyRobot R9500). In 24 dairy cows, 12 in early (<80 DIM) and 12 in late lactation (>180 DIM), 294 milkings were recorded during 12 consecutive days. Teat cup detachment was set at a quarter milk flow of 50, 87.5 or 125 g/min. Voluntary milking intervals varied similarly in cows in early (6.1–14.8 h) and late lactation (6.3–15.7 h). Total milk yield, milk production per h and average milk flow were higher in early than in late lactation cows. Total milk yield per milking did not differ between detachment levels. The mean milking time was reduced by up to 1.5 min at the highest compared to the lowest detachment level mainly in early lactation cows (P < 0.05). However, no significant effect of the detachment level on milking time was observed at milking intervals >10 h. Average milk flow was higher at milking intervals >10 h than ≤10 h (P < 0.05). In the early lactation cows (only) the average milk flow increased with higher detachment levels (P < 0.05). Teat condition did not differ among detachment settings or milking intervals. In conclusion, teat cup detachment up to 125 g/min reduces milking time in both early and late lactation without a loss of milk yield or affecting the teat condition. Combined with a higher average milk flow through avoiding too short milking intervals, the total milking time and hence stall occupancy can be optimized by early teat cup detachment.

This Research Paper addresses the hypothesis that using teatcups with automatic valves, without cutting off the vacuum prior to cluster removal, could increases the risk of mastitis and affect other milking variables on goats. A first trial used 46 intramammary infection (IMI)-free goats that had been milked with normal teatcups (without automatic valves) during a pre-experimental period of 8 ± 2 d postpartum. These animals were divided into two groups (n = 23), randomly assigning each group to teatcups with automatic valves (teatcups A) or without automatic valves (teatcups B) for a 20-week experimental period. During this period, several strategies were applied to increase teat exposure to pathogens in both experimental groups. In the first eight weeks of the experimental period, the new IMI rate per gland was significantly higher (P < 0·05) in the group of animals milked with teatcups A (6 of 46; 13%) than in the group milked with teatcups B (1 of 46; 2%). However, throughout the rest of the experimental period the same number of glands appeared with new IMI (n = 7) in both animal groups. SCC was higher in goats milked with teatcups A, but no significant differences were found in the remaining variables (milk production and composition, frequency of liner slips + teatcup fall-off). In a second experiment, in a crossover design (54 goats in fourth month of lactation, 2 treatments – teatcups A and B – in 2 experimental periods each lasting 1 week), no differences were observed in total milk, average milk flow, total milking time or teat thickness changes after milking between both teatcups. However, teatcups A worsened slightly the maximum milk flow. We concluded that the use of teatcups with automatic valves, without cutting off the vacuum prior to cluster removal, increases the risk of mastitis on goat livestock farms.

The main objective of this experiment was to evaluate the effects of two milking intervals (8 and 16 h) on milk constituents (fat, protein, lactose, dry matter, and log10 SCC) of nineteen Istrian × Awassi × East-Friesian crossbred ewes in different milk fractions (0–25, 25–50, 50–75 and 75–100%) during the course of milking and in machine stripping (MS) milk. Furthermore, we sought to determine the effect of the two milking intervals on milking characteristics (average milk flow rate, peak milk flow rate, machine-on time, total milk yield, and milk production rate) and whether each milk constituent within each milking interval is best described by a linear, quadratic, or cubic function. Average milk flow rate and milk yield per milking decreased in the 8 h milking interval compared to the 16 h milking interval (P < 0.05). Peak milk flow rate, machine-on time, and milk production rate were not different between the two milking intervals. Overall, milk fat content, dry matter content, and log10 SCC increased in the 8 h milking interval compared to the 16 h milking interval (P < 0.05). Milk protein content did not change through the main milk fractions at either milking interval. Milk lactose content did not change through the milk fractions at the 8 h milking interval, whereas it decreased in the 75–100% and stripping milk fractions at the 16 h milking interval (P < 0.05). The 0–25% and stripping milk fractions contained the highest log10 SCC compared to all other milk fractions (P < 0.05). Changes of milk fat and dry matter content throughout milking were best described by quadratic functions, whereas milk protein content, milk lactose content, and log10 SCC were best described by different functions depending on the milking interval. These results demonstrate that milking interval influenced all milk constituents in various milk fractions during the course of ewe milking. Moreover, milking characteristics such as average milk flow and total milk yield, and the appropriate mathematical function to characterize milk constituents throughout a milking, were affected by milking interval.

Health-conscious consumers are increasingly paying attention to healthy diets and focusing on natural bioactive compounds in foods and their effects on mental health. This opens new opportunities for the study of artisanal cheeses as biofunctional foods. In the work described in this Research Communication, the gamma-aminobutyric acid (GABA) content of seven different Portuguese cheeses produced from unpasteurized cow, sheep, and goat milk and granted with protected designation of origin (PDO) status was analysed. The PDO cheeses made from cow milk analysed in this study were São Jorge (3, 4, 7, 12 and 24 months of maturation) and Pico cheeses. PDO cheeses made from sheep milk were Serra da Estrela, Serpa, Nisa and Azeitão. Cheeses made from sheep and goat milk included Beira Baixa yellow cheese. The GABA content in the Azorean PDO cheeses (made from cow milk) ranged from 1.23 to 2.64 g/kg of cheese. Higher variations in GABA content were observed in cheeses made from sheep and goat milk (0.73–2.31 g/kg). This study provides information on the GABA content in different Portuguese PDO cheeses and shows that hard or semi-hard ripened cheeses are a suitable matrix for GABA production by lactic acid bacteria.

It was previously found that low concentrations of oleic acid in the growth medium inhibited the growth of Streptococcus cremoris strain C 13. However, a variant of this strain has now been isolated which is capable of growth in relatively high concentrations of oleic acid. This was achieved by the extended incubation of inocula of strain C 13 in milk containing various concentrations of oleic acid.