Total bacterial and coliform count
The total bacterial count (TBC) in milk samples was measured and compared to palestinian standard (PS 600:2024) and California “grade A” milk standards
(California Department of Food and Agriculture, 2025) for raw cow’s milk as shown in (Fig 1). All samples exceeded the Palestinian Standard limits (log 6.00 cfu/ml). The TBC values ranged from log 6.14±0.20 cfu/ml (S8) to log 6.98±0.09 cfu/ml (S6) with average value log 6.65 cfu/ml, indicating high bacterial contamination across all samples. In addition, all samples also exceeded the California milk standards (CS) of log 4.70 cfu/ml. The results in this current study are inline with those done in raw milk by
Aaku et al., (2004) in Botswana,
Al-Tarazi et al., (2003) in Jordan and
Karimuribo et al., (2005) in Tanzania which reported higher bacterial count above recommended level by standards in most of the samples that were tested. The high TBC values in all samples suggest significant bacterial contamination, likely due to poor hygiene practices during milking, storage, or transportation. The lack of compliance with both PS and CS standards highlights the need for improved handling and cooling practices to reduce bacterial growth
(Sarkar, 2016).
Coliforms are gram-negative, aerobic or facultative anaerobic, non-spore-forming rods that ferment lactose and produce gas and acid at 35
oC. They typically live in the gastrointestinal tracts of both humans and animals
(Mounier et al., 2019). For more than a century, coliforms have been used to detect fecal contamination in dairy, water and other food items
(Martin et al., 2023). These organisms are a sign of unhygienic production and/or inappropriate handling of milk or milk utensils when they are found in milk and milk products
(Al-Iedani and Ghazi, 2016). Since Coliform limits are not specified in the Palestinian raw milk standard (PS 600:2024), our results were evaluated against the stringent California standards. According to these international standards, the acceptable limit for coliforms in raw milk is typically £ log 2.88 cfu/ml. In this study, TCC values (Fig 2) ranged from log 1.50 cfu/ml (S6) to log 5.59 cfu/ml (S11) with average value log 4.04 cfu/ml. The results showed that, 31% raw milk samples coincided with the CS, while the remaining 69% had TCC above the standard. The results obtained are lower to those of
Al-Tarazi et al. (2003), who obtained mean values of TCC log 5.5 cfu/ml and higher to the findings of
Ismail et al., (2024), who obtained mean values of TCC log 3.64 cfu/ml. The high TCC values in most samples further emphasize the need for better hygiene practices, such as proper cleaning of milking equipment, udder sanitation and immediate cooling of milk after collection.
Physicochemical analysis
Chemical properties
The physicochemical properties of raw milk samples in the study were shown in Table 1. The average fat content (3.57±0.8 per cent) meets the PS (≥3 per cent), even though the range (2.32 to 4.60 per cent) shows that some samples are below the requirement. According to this study, 77% of raw milk samples coincided with the standard, while the remaining 23% had fat content below the standard. The average fat content in this study is similar with earlier findings of
Yakubchak et al., (2021) and
Malacarne et al., (2013) who reported a fat content of 3.5±0.1% and 3.71±0.3 for milk obtained in private households and raw bulk milk samples respectively. Though, higher values of fat content (4.3%) was reported from milk of cows from dairy farms were reported by
Lindmark-Månsson et al. (2003) as compared to the present study. However, the average fat content in the study were greater than the earlier findings of
Kazeminia et al., (2023) who reported a fat content of 3.13±0.36% from milk collection centers in Qazvin, Iran. Because the cost per liter of milk is determined in part by its fat content. The current outcome is therefore great news for smallholder producers of raw cow milk. Mean SNF content was 8.51±0.9%, with a range of 6.63 to 10.20% observed for minimum and maximum values in the samples. The PS (≥8.5 per cent) is nearly met by the mean SNF content. Approximately similar results were reported by
Duguma (2022),
Gemechu (2016) and
Mohammed and Abdel-Aall (2024).
The average protein content of milk samples ranged from 2.43% to 4.37% with an average of 3.14±0.5. This result is in line with 3.12 and 3.14% reported by
Dehinenet et al., (2013) and
Azeze and Tera (2015) respectively. However, this results lower than 3.40 and 3.98% reported by
Haftu and Degnet (2018) and
Gemechu and Amene (2021), in cow milk of Western Shewa and Bench Maji region respectively. The genetic variability of the milking cow or environmental factors such as feed, lactation stage, milking interval, season and location could be the cause of this variation.
Another important component was lactose, a sugar found in milk. In this study the overall average of lactose content was 4.56±0.5 per cent. According to the European Union Quality standards for unprocessed whole milk the lactose content should not be less than 4.2 per cent
(Assen and Abegaz, 2024;
Tamime, 2009). Conversely,
(O’Connor, 1995) recommended the normal range of cow milk lactose content as 4.7 to 4.9%. The present study found that the lactose content of milk was higher than that of the study conducted in the Peja region
(Loshi et al., 2023), which found 4.34±0.2 per cent and comparable to that of the study conducted in Basrah, Iraq
(Al-Iedani and Ghazi, 2016), which found 4.61±0.6. Milk samples appears to contain a moderate amount of lactose, which is within the typical range for dairy products. The composition of milk can fluctuate due to interval between milking, stage of lactation, age and health of the cow. Milk lactose is influenced considerably by the health of the udder as well as the cow’s metabolic and energy balance
(Antanaitis et al., 2024).
Physical properties
Based on the physical characteristics (Table 1) of milk, the most widely used techniques include the density and freezing point
(Ionescu et al., 2023). As a legal standard, the freezing point is measured to ascertain whether milk has been diluted with water. When water is adulterated with the milk, the salts dissolved in the serum are diluted and the freezing point is raised
(Kamthania et al., 2014). In this study, although some samples de
viate with values as low as -0.576
oC and as high as -0.419
oC, the average freezing point (-0.522±0.04) falls within the PS typical range (-0.520
oC to -0.560
oC). However this results agreed with 0.520±0.001 reported by Abd
Elrahman et al., (2009) for freezing points of raw milk in Blue Nile Dairy Company (Sudan).
The density of milk samples ranged from 1.020 to 1.035 with an average of 1.027±0.01, close to the standard of 1.028 to 1.035 g/cm
3. About 46% of the samples were lower than the normal density value which is partially due to adulteration by addition of water. However, low density of the milk does not automatically mean it has been adulterated with water and may for an example be the result of a cow suffering from mastitis
(Sharma et al., 2011). This study is similar to one conducted by
(Orregård, 2013), whose findings indicated that approximately 33% of farmer samples did not fall within the acceptable density limit. Two of the thirteen tested milk samples were discovered to be tampered with by adding water. The milk’s density could be diminished due to this adulteration.
Milk adulterants
For a variety of reasons, although mostly to mislead consumers and boost profits, milk is adulterated with ingredients like carbonates, formalin, salt and starch
(Momtaz et al., 2023). Carbonates, are used to cover the acidity and sour taste of the milk to avoid rejection in dairy collection hubs and production units
(Irshad et al., 2021). Even though formalin, a formaldehyde solution, is extremely toxic, act as preservatives and extend the milk’s freshness
(Ionescu et al., 2023). Sodium chloride, or salt, is added mainly to get a correct lactometer reading by increasing the milk density. However, starch is added to raw milk to increase its viscosity and texture, especially when the milk has been diluted
(Kailasapathy, 2015). Ingestion of adulterated milk may have a harmful consequence on human health because of the entrance of toxic substances or loss of nutritional value
(Abbas et al., 2024).
The presence of chemical adulterants in raw milk samples was tested and the results are presented in Table 2. All samples tested negative for carbonate, formalin, starch and salt adulteration. This indicates that the milk samples were free from these common chemical adulterants, which is a positive finding. However, continuous monitoring is necessary to ensure that milk remains free from such adulterants, as their presence can have serious health implications. These results suggest that the owners of raw milk stores in the Hebron district have moral and religious convictions, particularly in light of the infrequent and limited inspection visits from the relevant ministries to these establishments. These finding agree with those reported by
El-Bessary (2006) and
Mansour et al., (2012), while
Salama et al., (2023) found that 26.67% and 13.33% of market raw milk samples were formalin and carbonate positive respectively.
