Fatty Acids of Semi-Hard Cheese Made from Milk of Goats Fed Diets Enriched with Extruded Linseed or Pumpkin Seed Cake

The addition of oilseeds and their cakes to the diets of lactating dairy goats is an alternative to supplemental feeding, which improves the lipid profile of goat cheeses. The objective of the present study was to evaluate the effect of a diet containing extruded linseed or pumpkin seed cake on the fatty acid profile of semi-hard cheese made from goat milk. The research was carried out with 28 French Alpine goats fed the following diets: 1—basal diet based on extruded soybean and soybean meal; 2—basal diet with 90 g/kg DM extruded linseed (ELS); and 3—basal diet with 160 g/kg DM pumpkin seed cake (PSC). Bulk milk from three separated milk tanks at three samplings was used for the manufacture of four traditional semi-hard cheeses from each milk tank at each sampling on the family farm. The ELS and PSC diets increased fat content in the cheese. The ELS feeding increased the proportion of C18:1 c9, C18:2 c9t11, and C18:3 n-3 in cheese and lowered C8:0, C6:0, and C16:0, while PSC resulted in the highest C18:2 n-6 proportions in the cheese. The health-promoting index was the highest in the cheese of ELS. The ELS had a contribution to higher nutritional and health quality of semi-hard traditional goat cheeses, thus representing a food with health-promoting properties.

Opposite Direction for Seasonal Variation of Aflatoxin M1 in Bulk Milk and Aflatoxin B1 in Rations: Results From a Prospective Study in Selected Dairy Farms of Qazvin Province, Iran

The presence of aflatoxin M1 (AFM1) in 24h bulk milk and aflatoxin B1 (AFB1) in concurrent total mixed rations (TMR) and feed ingredients were assessed in 12 large dairy operations. The bulk milk was sampled on days 1, 15 and 30 during winter and summer (n=72). Total mixed rations (n=48) and feed ingredients (n=230) were sampled two times with a 30-day interval. Aflatoxin was measured using direct competitive ELISA kits with detection limits of 1-81 ngkg−1 for milk and 1.25-101.25 ngkg−1 for feeds. Aflatoxin M1 was identified in all milk samples (100%), ranging from 2.03 to >81 ngkg−1, with a median of 70 ngkg−1 and averaging 61.25±28.91 ngkg−1 in winter and 54.20±25.51 ngkg−1 in summer (P=0.279). Contaminations <81 ngkg−1 (below the Iranian standard of 100 ngkg-1) were detected in 76% (n=55/72) of samples. Contaminations >81 ngkg−1 were detected in 24% (n=17/72) of samples and were more frequent in winter than in summer (42% vs. 6%). Sixty-nine percent of the winter milk samples (n=25/36) had contaminations above the median (70 ngkg−1). A reverse result was detected in summer. The chance of contaminations above median was higher in winter than in summer (OR=5.33, P=0.007). All TMR and ingredient samples had higher AFB1 contaminations in summer (P<0.05). Six TMR samples had non-detectable (<1.25 ngkg-1) values (5 in winter) and 7 samples had levels >101.25 ngkg-1 (all in summer). The chance of TMR contamination above the median (716 ngkg-1) was 5.57 times higher in summer than in winter (P=0.002). Seventy percent of the TMR samples had contaminations above the median in summer. Elevated levels of AFB1 of rations in summer (1375.50±905.02 vs. 537.05±558.79; P<0.002) did not result in elevation of AFM1 in milk, probably due to reduced AFB1 metabolism in the liver and lower dry matter intakes caused by heat stress. The AFB1 content of grain mix succeeded by corn silage, wet beet pulp, dry beet pulp and alfalfa hay were correlated with TMR contamination. Ration AFB1 and milk AFM1 were not correlated. Based on the results, a great majority of milk produced in the studied farms could have AFM1 contaminations below the Iranian standard limit (100 ngkg-1). Contaminations below 50 ngkg-1 appear to be achievable and affordable. Intensifying the controlling measures in summer, when the feed contaminations are elevated, may reduce the overall milk contamination.

Influence of milk used for cheese making on microbiological aspects of Camembert-type cheese

Camembert-type cheeses are surface mould-ripened soft cheeses obtained with Penicillium camemberti. Soft cheeses are more frequently associa ted with foodborne disease outbreaks than hard and semi-hard cheeses. During our work, three Camembert-type cheeses were prepared on a pilot/small industrial scale. The first cheese was made from bulk milk and pasteurized at 74 °C for 15 seconds. The second and third cheese were prepared from one type of milk and were heat-treated at 72 °C for 60 seconds. The microbial contamination with Salmonella spp. and Staphylococcus aureus of the three Camembert-type cheeses was evaluated. The food-related stress survival of Salmonella spp. and S. aureus isolates originated from the cheese samples was assayed. The antibiotic suscep tibility of the bacterial isolates was determined by the disk diffusion method, using 12 and 16 different antibiotics respectively. Based on the results, the first cheese sample contained the highest number of Salmonella bacteria; S. aureus was detected only in the first sample. According to the results of antibiotic susceptibility of the Salmonella, isolates showed susceptibility to the majority of assayed antibiotics and resistance to trimethoprim, chloramphenicol, amikacin, and cefotaxime. The S. aureus isolates showed resistance to trimethoprim and displayed intermediate resistance to levofloxacin and ciprofloxacin.

Farm Silage Facilities and Their Management for the Prevention of Anaerobic Bacteria Spore Contamination in Raw Milk

At feed-out, aerobic spoilage of silage enables an increase in anaerobic spore-forming bacteria (ANSB) that may enter the total mixed ration (TMR). The aim of our study was to understand whether in hot summers the silage structures and management may affect the level of ANSB in milk for long-ripening cheese production. A survey of silage facilities, management, and their relationships with silage, TMR, feces, and milk ANSB most probable number (MPN) content was conducted in the Po Valley during summer months. Silo type did not affect the mean ANSB, but only the wideness of their value distributions, with a narrow range for bags and a wider range for bunkers. The unloading equipment affected the ANSB count; the front-end loader with cutter was associated with a lower ANSB count—probably as a result of the reduced surface left after daily silage removal. Silo length and daily removed face width were the main factors affecting contamination of silage by spore-forming bacteria during summer, with longer silos and wider surface removal reducing ANSB contamination—probably as a consequence of reduced aerobic spoilage at the silage surface. The silage contamination by spore-forming bacteria within a log10 2 MPN g−1 allowed a low concentration of spore-forming bacteria at the farm bulk milk tank level. Fecal ANSB levels did not factor into the regression that explains the ANSB in farm milk. It has been found that silage facilities’ features and their management are an important first step to reduce the extent of ANSB contamination at the farm level.

Bulk Milk Tank Samples Are Suitable to Assess Circulation of Tick-Borne Encephalitis Virus in High Endemic Areas

A reliable surveillance strategy of tick-borne encephalitis virus (TBEV) is necessary to ensure adequate disease control measures. However, current approaches assessing geographical TBEV circulation are ineffective or have significant limitations. In this study we investigated a total of 1363 goat and 312 sheep bulk tank milk samples for the presence of TBEV. Samples were collected from systematically selected farms in Lithuania every 4–5 days from April to November in 2018 and 2019. To validate results, we additionally tested 2685 questing ticks collected in the vicinity of milk collection sites. We found 4.25% (95% CI 3.25–5.47) and 4.48% (95% CI 2.47–7.41) goat and sheep milk samples to be positive for TBEV, respectively. Furthermore, geographical distribution of TBEV in milk samples coincided with the known TBE endemic zone and was correlated with incidence of TBE in humans in 2019. When sampling time coincides, TBEV detection in milk samples is as good a method as via flagged ticks, however bulk milk samples can be easier to obtain more frequently and regularly than tick samples. The minimal infectious rate (MIR) in ticks was 0.34% (CI 95% 0.15–0.64). Therefore, our results confirm that testing milk serves as a valuable tool to investigate the spatial distribution of TBEV at higher resolution and lower cost.

Screening of Regulated and Emerging Mycotoxins in Bulk Milk Samples by High-Resolution Mass Spectrometry

In this work, a retrospective screening based on ultra-high-performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS) based on Orbitrap-Q-Exactive Focus™ was used to check the occurrence of regulated and emerging mycotoxins in bulk milk samples. Milk samples were collected from dairy farms in which corn silage was the main ingredient of the feeding system. The 45 bulk milk samples were previously analyzed for a detailed untargeted metabolomic profiling and classified into five clusters according to the corn silage contamination profile, namely: (1) low levels of Aspergillus- and Penicillium-mycotoxins; (2) low levels of fumonisins and other Fusarium-mycotoxins; (3) high levels of Aspergillus-mycotoxins; (4) high levels of non-regulated Fusarium-mycotoxins; (5) high levels of fumonisins and their metabolites. Multivariate statistics based on both unsupervised and supervised analyses were used to evaluate the significant fold-change variations of the main groups of mycotoxins detected when comparing milk samples from clusters 3, 4, and 5 (high contamination levels of the corn silages) with cluster 1 and 2 (low contamination levels of the corn silages). Overall, 14 compounds showed a significant prediction ability, with antibiotic Y (VIP score = 2.579), bikaverin (VIP score = 1.975) and fumonisin B2 (VIP score = 1.846) being the best markers. The k-means clustering combined with supervised statistics showed two discriminant groups of milk samples, thus revealing a hierarchically higher impact of the whole feeding system (rather than the only corn silages) together with other factors of variability on the final mycotoxin contamination profile. Among the discriminant metabolites we found some Fusarium mycotoxins, together with the tetrapeptide tentoxin (an Alternaria toxin), the α-zearalenol (a catabolite of zearalenone), mycophenolic acid and apicidin. These preliminary findings provide new insights into the potential role of UHPLC-HRMS to evaluate the contamination profile and the safety of raw milk to produce hard cheese.

Management of high cows-share-contribution of SCC to the bulk milk tank by acoustic pulse technology (APT)

A cow with mastitis has a high somatic cell count (SCC) in its milk. Cow-share-contribution of somatic cells to the bulk milk tank (BMTSCC) refers to the relative addition made by each cow’s milk to the bulk tank’s SCC. Since bulk milk is graded and priced according to the BMTSCC, high-yielding cows with mastitis are the main contributors to penalizations in milk price. The benefits of acoustic pulse technology (APT) application to tissues are well documented, including its anti-inflammatory effect and restoration of tissue function by triggering natural healing processes. An APT-based device was developed specifically for treating mastitis in dairy cows. It enables rapid and deep penetration of the acoustic pulses over a large area of the udder in a single session. A study was performed on six farms with a total of 3,900 cows. One unit of cow-share-contribution equaled the addition of 1,000 cells to each mL of the bulk milk volume above the mean BMTSCC. A total of 206 cows were selected: 103 were treated with APT and 103 served as controls. All of the cows contributed over 1.5 units to the BMTSCC at the time of treatment. Seventy-five days after APT treatment, 2 of the 103 treated cows (1.9%) were culled, compared to 19 (18.5%) of the 103 control cows, as well as infected quarter dry-off in 5 others (4.85%). Overall success was defined as a decrease of >75% in cow-share-contribution from treatment time in two of the three monthly milk recordings following treatment. Results indicated 57.3% success for the APT-treated cows vs. 14.6% for the untreated control groups. Highest share-contribution provide an additional tool for the farmer’s decision of how to control BMTSCC. Because the cow-share-contribution value is relative to herd size and BMTSCC, this study included a similar number of cows, with similar SCC and milk yield from each of the six herds.

Occurrence and aetiology of subclinical mastitis in water buffalo in Bangladesh

Subclinical mastitis (SCM) in water buffalo is a production disease associated with decreased milk yield and impaired milk quality and safety. Water buffalo is an important livestock species in Bangladesh, but information about the occurrence and aetiology of SCM in this species is scarce. A cross-sectional study was conducted as part of the Udder Health Bangladesh Programme to (i) determine the occurrence of SCM and bulk milk somatic cell count (SCC) in water buffalo in Bangladesh, (ii) identify pathogens causing SCM and (iii) evaluate penicillin resistance in isolated staphylococci strains. Sixteen buffalo farms in the Bagerhat and Noakhali regions of Bangladesh were selected for study and a bulk milk sample was collected from each farm. In addition, 299 udder quarter milk samples were collected from 76 animals. The bulk milk samples were assessed by direct SCC and the quarter milk samples by California mastitis test (CMT). The occurrence of SCM calculated at quarter and animal level was 42.5 and 81.6%, respectively. Milk samples from 108 CMT-positive quarters in 48 animals and 38 randomly selected CMT-negative quarters in 24 animals were investigated using bacteriological culture. Estimated mean bulk milk SCC was 195 000 cells/ml milk (range 47 000– 587 000 cells/ml milk). On culture, estimated quarter-level intramammary infection (IMI) was 40.4%. The identity of isolated bacteria was confirmed by MALDI-TOF mass spectrometry. Non-aureus staphylococci (NAS) were the most common pathogens (24.7%) and, among 36 NAS tested, 36.1% were resistant to penicillin. Thus there was high occurrence of SCM on the study farms, with relatively high penicillin resistance in NAS. Further studies are needed to identify underlying risk factors and develop an udder health control strategy for water buffalo in Bangladesh.