Microbial quality of raw cow milk and its predictors along the dairy value chain in Southwest Ethiopia

Bacteriological quality and predictors of raw meat collected from municipal slaughterhouse and butcher shops in northeast, Ethiopia

Background

Meat is a good source of protein in the human diet, and more than three-quarters of the world's population consumes it. It is the most perishable food item since it has enough nutrients to enable microbial growth. In underdeveloped nations, animals are routinely slaughtered and sold in unsanitary conditions, compromising the bacteriological quality and safety of the meat received from the animals. To protect customers' health from numerous foodborne diseases this study aimed to determine the microbial quality and predictors of meat along the meat value chain in Northeast, Ethiopia.

Objective

To determine the bacteriological quality of meat and its predictors obtained from the Dessie City Administration's municipal slaughterhouse and butcher shops.

Materials and methods

A laboratory-based cross-sectional study design was used. In total 177 meat and 354 swab samples were collected. In addition, 177 meat handlers were randomly selected for knowledge, attitude, and practice assessment. All the samples were analyzed for the presence and counts of total viable count, total coliform count, fecal coliform count, and S. aureus. Multiple linear regression and student T-tests were used to analyze the data. Statistical significance was defined at a p-value of less than 0.05.

Results

The total viable count of meat samples collected from slaughterhouse and butcher shops were 5.17 ± 0.13 and 6.5 ± 0.87 log CFU/g, respectively. The overall mean total viable count of the meat samples was 5.8 ± 0.1 log CFU/g. Meat samples collected from butcher shops were more highly contaminated than those collected from slaughterhouse. Hand hygiene of meat handlers, the microbial quality of water, and the educational status of meat handlers are all significant predictors of the microbial quality of raw meat along the meat value chain.

Conclusion and recommendation

The meat microbial quality is poor and deteriorates along the meat value chain. The hands of meat handlers, the microbial quality of water used to wash the hands of meat handlers, and the educational status of meat handlers significantly affect the microbial quality of raw meat along the meat value chain. Hence, measures should be taken to improve the personal hygiene status of meat handlers and the quality of water used to wash hands and meat contact surfaces.

Seasonal Comparison of Microbial Hygiene Indicators in Raw and Pasteurized Milk and Cottage Cheese Collected across Dairy Value Chain in Three Regions of Ethiopia

A longitudinal design with a simple random sampling method was used to collect and compare microbial hygiene levels between the dry season (January to April) and wet season (June to August). A total of 456 milk and cottage cheese samples were collected from each site along the dairy value chain from three regions. Enumeration of total aerobic mesophilic bacteria (APC), total coliforms (TCC), and Escherichia coli (EC) was performed according to standard methods. Independent t-tests were employed to assess the significant variation at (p < 0.05) between the two seasons. The cumulative result of APC of 7.61 log cfu/mL and g and TCC of 3.50 log cfu/mL in the dry season were significantly higher than the wet season of 7.15 log cfu/mL and 2.49 log cfu/mL, respectively, whereas generic E. coli count (EC) was significantly higher in the wet season (0.70 log cfu/mL and g) than that in the dry season (0.40 log cfu/mL and g). The results of hygienic indicator microbial load significantly varied with season. Hence, hygienic milk production and handling practices that comprehend seasonal influence should be implemented to improve the safety of milk.

Extending the Shelf Life of Raw Milk and Pasteurized Milk with Plantaricin FB-2

Raw milk and pasteurized milk are characterized by a short shelf life, and drinking expired raw milk and pasteurized milk causes illness. In the study, Plantaricin FB-2 (extracted from Lactiplantibacillus plantarum FB-2) was added to liquid milk. By evaluating the microbial growth, acidity changes, protein content, and sensory changes in raw milk and pasteurized milk during storage, it was found that when Plantaricin FB-2 was added at 0.4 g/kg, the shelf life of raw milk was extended by 3 days (7 days if not added). The shelf life of pasteurized milk with Plantaricin FB-2 was extended to 31 days (25 days in the control group), and the optimal amount was 0.3 g/kg. This confirmed that Plantaricin FB-2 can effectively prolong the shelf life of raw and pasteurized milk. This study provides valuable information for the application of bacteriocins produced by Lactiplantibacillus plantarum in raw milk and pasteurized milk to improve their shelf life.

Correlation Analysis of Microbial Contamination and Alkaline Phosphatase Activity in Raw Milk and Dairy Products

Microbial contamination in raw milk and dairy products can detrimentally affect product quality and human health. In this study, the aerobic plate count, aerobic Bacillus abundance, thermophilic aerobic Bacillus abundance, and alkaline phosphatase activity were determined in 435 raw milk, 451 pasteurized milk, and 617 sterilized milk samples collected from 13 Chinese provinces (or municipalities). Approximately 9.89% and 2.22% of raw milk and pasteurized milk samples exceeded the threshold values for the aerobic plate count, respectively. The proportions of aerobic Bacillus in raw milk, pasteurized milk, and sterilized milk were 54.02%, 14.41%, and 1.30%, respectively. The proportions of thermophilic aerobic Bacillus species were 7.36% in raw milk and 4.88% in pasteurized milk samples, and no bacteria were counted in sterilized milk. Approximately 36.18% of raw milk samples contained >500,000 mU/L of alkaline phosphatase activity, while 9.71% of pasteurized milk samples contained >350 mU/L. For raw milk, there was a positive correlation between the aerobic plate count, the aerobic Bacillus abundance, and the alkaline phosphatase activity, and there was a positive correlation between the aerobic Bacillus abundance, the thermophilic aerobic Bacillus count, and the alkaline phosphatase activity. For pasteurized milk, there was a positive correlation between the aerobic plate count, the aerobic Bacillus abundance, and the thermophilic aerobic Bacillus count; however, the alkaline phosphatase activity had a negative correlation with the aerobic plate count, the aerobic Bacillus abundance, and the thermophilic aerobic Bacillus abundance. These results facilitate the awareness of public health safety issues and the involvement of dairy product regulatory agencies in China.

Evaluation of the Effect of Wastewater Irrigation on the Microbiological Quality of Vegetables in Northeast Ethiopia: Implication for Food-Borne Infection and Intoxications

BACKGROUND

Cultivation of vegetables using untreated wastewater is a common phenomenon in many drought-prone areas of the world. Consumption of such microbiologically unsafe vegetable increase the risk of food-borne diseases. As a result, evaluating the effect of wastewater irrigation on the microbiological quality of vegetables would be beneficial to consumers' health.

METHOD

A total of 192 vegetable samples (lettuce, cabbage, carrot, and tomato) and 64 irrigation water samples were collected and analyzed for total bacteria and coliform count using a standardized protocol over a 4 month period. One-way analysis of variance and Pearson correlation coefficient was used to analyze the data. Statistical significance was defined at a P-value of less than 0.05.

RESULT

Carrots were the least polluted vegetable, according to the study, while cabbage had the highest contamination levels. The mean bacterial count among the vegetables differs significantly (P < 0.05). The fecal coliform counts of the irrigation wastewater exceed the international wastewater irrigation standards. The mean microbial count between vegetables and water samples showed a significant positive relationship (P < 0.05). All of the analyzed vegetable samples were of borderline microbial quality for fecal coliform bacteria.

CONCLUSION

Irrigation wastewater has a low microbiological quality, which significantly contributes to the contamination of vegetables grown on it.

RECOMMENDATION

Measures should be taken to improve the microbial quality of wastewater as well as the quality of vegetables grown in order to protect consumers' health from food-borne diseases.

Microbial Properties of Raw Milk throughout the Year and Their Relationships to Quality Parameters

Raw milk microbiota is complex and influenced by many factors that facilitate the introduction of undesirable microorganisms. Milk microbiota is closely related to the safety and quality of dairy products, and it is therefore critical to characterize the variation in the microbial composition of raw milk. In this cross-sectional study, the variation in raw milk microbiota throughout the year (n = 142) from three farms in China was analyzed using 16S rRNA amplicon sequencing, including α and β diversity, microbial composition, and the relationship between microbiota and milk quality parameters. This aimed to characterize the contamination risk of raw milk throughout the year and the changes in quality parameters caused by contamination. Collection month had a significant effect on microbial composition; microbial diversity was higher in raw milk collected in May and June, while milk collected in October and December had the lowest microbial diversity. Microbiota composition differed significantly between milk collected in January−June, July−August, and September−December (p < 0.05). Bacterial communities represented in raw milk at the phylum level mainly included Proteobacteria, Firmicutes and Bacteroidota; Pseudomonas, Acinetobacter, Streptococcus and Lactobacillus were the most common genera. Redundancy analysis (RDA) found strong correlations between microbial distribution and titratable acidity (TA), fat, and protein. Many genera were significantly correlated with TA, for example Acinetobacter (R = 0.426), Enhydrobacter (R = 0.309), Chryseobacterium (R = 0.352), Lactobacillus (R = −0.326), norank_o__DTU014 (R = −0.697), norank_f__SC-I-84 (R = −0.678), and Subgroup_10 (R = −0.721). Additionally, norank_f__ Muribaculaceae was moderately negatively correlated with fat (R = −0.476) and protein (R = −0.513). These findings provide new information on the ecology of raw milk microbiota at the farm level and contribute to the understanding of the variation in raw milk microbiota in China.