monitoring the hygiene of raw milk from farms to milk retailers

Peer-review under responsibility of the Faculty of Animal Sciences and Agricultural Technology, Silpakorn University doi: 10.1016/j.aaspro.2016.12.016 ScienceDirect International Confer

Agriculture and Agricultural Science Procedia 11 ( 2016 ) 95 – 99

2210-7843 © 2016 Published by Elsevier B.V This is an open access article under the CC BY-NC-ND license

( http://creativecommons.org/licenses/by-nc-nd/4.0/ ).

Peer-review under responsibility of the Faculty of Animal Sciences and Agricultural Technology, Silpakorn University

doi: 10.1016/j.aaspro.2016.12.016

ScienceDirect

International Conference on Inventions & Innovations for Sustainable Agriculture 2016, ICIISA

2016 Monitoring the Hygiene of Raw Milk from Farms to Milk Retailers

Khanitta Ruangwittayanusorna,*, Doungnapa Promketa, Anut Chantiratikula

a Department of Agricultural Technology, Faculty of Technology, Mahasarakham University, Maha Sarakham 44150, Thailand

Abstract

Milk from dairy cattle is a good source of nutrients for humankind around the world In Thailand, milk from dairy farms is generally transported to milk collection centre (MCC) and then transferred to milk processing plant However, some milk from MCC is sold

to local milk retailers The quality of raw milk is very important for people’s health Therefore, the aim of this study was to monitor milk hygiene during transfer from dairy farms to the MCC and from bulk tank milk to milk retailers by counting the microorganisms

in raw milk using standard plate count (SPC) method Raw milk samples of 15 dairy farms in Maha Sarakham province were collected in summer (Mar-Jun), raining (July-Oct) and winter (Nov-Feb) seasons After milking, raw milk was collected for SPC test Additionally, the time for milk transportation, environmental and milk temperatures in milk bucket were also recorded Those parameters were repeatedly recorded at MCC before being poured into the bulk tank Cooled raw milk in the bulk tank was sampled before packed in 5 kg plastic bag and carried to 9 milk retailers in town The results found that the average of time for milk transport from dairy farm to MCC was 76.29 min Milk temperatures decreased from farm to MCC for all seasons The SPC of milk at farm

in summer (5.812 log10CFU) was higher than in raining (5.743 log10 CFU) and winter (5.713 log10 CFU) (P<0.05) seasons The SPC from farm to MCC significantly increased (P<0.05) in all seasons The average of time for milk transportation from MCC to milk retailers were 89.44, 178.00 and 156.11 min (P<0.05) in summer raining and winter, respectively In conclusion, more attention should be paid to milk hygiene and temperature from milking in the farm through milk retailers, especially in the summer The microorganism could grow rapidly during milk transportation from farm to MCC in raining season Thus, cooling down the milk or rapid delivery of milk bucket to MCC should be considered seriously

© 2016 The Authors Published by Elsevier B.V

Peer-review under responsibility of the Faculty of Animal Sciences and Agricultural Technology, Silpakorn University

Keywords: milk transport; SPC; local market; milk chain

* Corresponding author Tel.: +661-894588228

E-mail address:khanitta.c@msu.ac.th

© 2016 Published by Elsevier B.V This is an open access article under the CC BY-NC-ND license

(http://creativecommons.org/licenses/by-nc-nd/4.0/)

Peer-review under responsibility of the Faculty of Animal Sciences and Agricultural Technology, Silpakorn University

1 Introduction

Thailand located in the tropical Southeast Asia Agriculture is the main occupation of the population Dairy farming was promoted under the 6th Thai National Economic and Social Development Plan by the government In that time there were many dairy farms established Large farm had spread in the Central region Dairy farm in the North-eastern usually small and medium farms The farms are the members of the nearest milk cooperative Mostly milk from dairy farm was sent to milk cooperative and forwards to milk processing factory Some milk was supply local market nearby farm

Milk is a good medium for the growth of various microorganisms, especially bacterial pathogens such as Bacillus

cereus, Listeria monocytogenes, Salmonella spp., Streptococcus, Strepphylococcus, Campylobacter spp etc Those

bacteria are case milk borne diseases for example tuberculosis, brucellosis and disease about gastroenteritis Raw milk from healthy cow may contain a low microbial load, but the microbial may increase multiply if it stored in some temperature (Richter et al., 1992) Range of temperature for growth of pathogenic bacteria is a normal temperature of

atmosphere environment Listeria monocytogenes, temperature ranges for growth = 29.3° to 112°F (-1.5° to 44°C) (Khan et al., 1972) Staphylococcus aureus, temperature range for growth = 43.8°- 122°F (6.5°- 50°C)

(Halpin-Dohnalek and Marth, 1989) These microorganisms are harmful for consumers For this reason raw milk should be cooled down immediately after milking Cold may delay the increase of microorganisms in milk After milking process, milk buckets were rapidly transported to milk collection centre (MCC) Nevertheless, only large farms can transport their milk to MCC immediately after milking For the small and medium farms, they did not carry and sent their milk buckets to MCC by themselves They employed the pickup truck to collect and transport their milk buckets

to the MCC It may take a longer time and the microorganism may multiply during the transport

In Thailand, like the other developing countries, some people consume milk purchased from milk shops which pasteurize the raw milk by themselves and used in many local drinking menus Raw milk supplied to milk retailers was from milk cooperatives in the province Raw milk was tested for the quality at the MCC and cooled down to 4 °C before packaged into 5 kg of plastic bags

Milk screening check was done at farms by stripping 2–3 milk jets from each cow teats into a foremilk or strip cup Examination of the milk for flocculation, colour changes, viscosity or other inconsistencies was performed Abnormal milk cow or sick cows were milked in the last milking separated from the healthy cows Milk in buckets was assessed again by sensory evaluation and an alcohol test at the MCC It was found that milk quality monitoring was done only

at MCC There was no milk monitoring previously and after the MCC The objective of this study was to monitor milk hygiene by counting the microorganism in raw milk using standard plate count (SPC) method during transport from dairy farms to the MCC and from bulk milk tank to milk retailers

1.1 Material and method

The experiment was done in Maha Sarakham province, 375 km from Bangkok, in the North East of Thailand Raw milk was monitored for hygiene at 4 stations, separated into 2 steps Step 1, at dairy farm and at MCC before pour to bulk tank Step 2, at bulk tank before seal in plastic pack and at the milk retailers

Step 1, raw milk was collected in the evening from 15 dairy farms for each season, there were 3 seasons, summer (Mar-Jun), raining (July-Oct) and winter (Nov-Feb) All farms used automatic milking Samples were collected in 10 mL sterile tubes and immerged in ice box and sent to the laboratory in the Faculty of Technology, Mahasarakham University Samples were processed within 24 h The time for milk transport, environmental temperatures and milk temperatures in milk bucket were also recorded After milk bucket arriving the MCC, raw milk sampling and those parameters were recorded again before being poured into the bulk tank

Step 2, transport from MCC to milk retailers, raw milk from all farms in the evening were poured into the bulk tank and cooled down to 4 C Before packing the raw milk in 5 kg plastic bag, milk was sampled and recorded for the bag

ID, and time for transportation At late evening, milk bags were kept in ice box and sent to milk retailers by pickup truck Those parameters were recorded again at milk retailers (9 milk retailers for each season)

1.1.1 Microorganism analysis

Standard Plate Count (SPC) test was used to determine the total bacterial contents in raw milk It is a test to detect all viable microorganisms that could grow aerobically on plate count agar The SPC tests could reflect the general hygiene condition of a sample The SPC was conducted as follows, diluting the raw milk sample 1:1000 by adding 0.01

ml of raw milk to 10 ml Ringer’s solution, pipetting 1.0 ml in a sterile dish Pour the solution into milk agar After agar turned solidified, incubating dish at 37C for 48 hours, counting the visible colonies on the plate The total bacterial content was the number of colonies on the plate x 1000

1.1.2 Statistical analysis

Step 1, the total bacterial content was transformed by log10 The total bacterial content and temperature for 2 places (farm and MCC) and 3 seasons (summer, raining season and winter) were analyzed using a 2x3 factorial in Completely randomize design by Analysis of variance with General Linear Model method Time for milk transportation was analysed in completely randomized design by ANOVA Step 2, data was analyzed separately from step 1 because raw milk from many farms had been poured together before step 2 However, data in step 2 was also analysed by the same model of step 1

2 Results

Raw milk from cows udder was usually contaminated by pathogenic microorganisms The average of total bacterial count (step 1) of raw milk from dairy farms was 5.756 log10cfu/ml (Table 1) All seasons seemed to supply raw milk with slightly higher than a limit 5.689 log10 cfu/ml set by Thai National Bureau of Agricultural Commodity and Food Standards The SPC of raw milk at farm in summer was highest, different from raining and winter season According

to Wilson et al (2012), it was reported that the total bacteria count using SPC of milk in summer was higher than others That is also accordant with Elmoslemany et al., (2010) which monitored hygienic quality of raw milk by total aerobic count (TAC) The rate of microbial contamination of cow’s raw milk is influenced by many factors such as the health status and hygiene of dairy cows, hygiene of the environment in which dairy cows are housed and milked etc (Cempírková, 2007)

The SPC was increased during transportation in all seasons. Each season has a different temperature, humidity in environment The different conditions cause microorganism growth to differ Time to transport milk from farm to MCC

in summer raining and winter were not different Time taken to supply milk to the MCC was rather long for all seasons Average time was 76.29+23.87 min The milk collecting system of this dairy milk community used the pickup truck to collect the bucket milk from the first farm and circulated to others farms and finish at the MCC The distance of farm from the MCC was not the subject for high SPC in a bucket for this study Increasing of microorganism in bucket was not significantly correlated with time to transport (P>0.05) However, in the report of Gran et al (2012)in Zimbabwe time to deliver milk was correlated with increasing in number of microorganism

Table 1 Total bacteria count (Log 10 cfu/ml) and time of transportation of milk samples collected from dairy farm and milk collection center in Maha Sarakham, Thailand

Time (min) 74.470 72.600 81.800 76.29 Different uppercase letter in the same row are significant difference (P<0.05) Different lowercase letter in the same column are significant difference (P<0.05) Milk in bucket temperature and environment temperature were significant in the interaction effect between place (farm and MCC) and seasons Temperature of milk in bucket was close to cow’s body temperature Milk temperature can reach 37-38 C and offers a good medium for the growth of mesophilic microorganism, and milk is stored at bacterial optimum growing temperature (Millogo et al., 2010) The temperature of milk was decreased when departed

to MCC The decreasing of milk temperature was different among each season which related to environmental temperature (Table 2)

Step 2, during transport from MCC to milk retailers The SPC in summer was highest both at MCC and milk retailer, according to raw milk at farm in summer The raw milk supplied is an important factor for milk hygiene Raw milk in winter shows the lowest SPC (Table 3) and minimum changes between MCC and milk retailer The report was accordant with the study in Bukina Faso in rainy and dry season (Millogo et al., 2010) Times to transport milk from MCC to milk retailers were high in raining and winter due to the inconvenience of transportation during the raining season and shorter daylight in winter

Table 2 The temperature (C) of milk in bucket and environment at farm and at MCC in summer raining and winter

Summer Raining Winter Summer Raining Winter Milk in bucket 36.067 A 35.600 B 35.667 B 35.733 AB 34.400 C 34.667 C

Environment 33.067 A 27.000 C 25.267 D 30.133 B 25.267 D 24.000 E

Different uppercase letter in the same row are significant difference (P<0.05)

Table 3 Total bacteria count (Log 10 cfu/ml) and time of transportation of milk samples collected from milk collection center and milk retailers in Maha Sarakham, Thailand

Milk retailer 5.7862 Ab 5.712 Ba 5.694 Cb

5.731 Time (min) 89.444 A 178.000 B 156.111 B 141.185 Different uppercase letter in the same row are significant difference (P<0.05)

Different lowercase letter in the same column are significant difference (P<0.05)

3 Conclusion

Milk hygiene during transport from farms to milk retailers in Maha Sarakham should be paid an attention, especially in the summer For milking at farm, milk in a bucket contains microorganism greater than standard milk quality Further research regarding milk hygiene monitoring should start at cow udder, environment and equipment in

a dairy farm

Duration of transport from farms to MCC, the lack of facilities to cooling raw milk below 10 °C before arrival to the MCC are the important reasons for microorganism growth Cooling system is costly for small holders The better way for small farmers is to keep the milk buckets in the sun shade during the wait for truck to pick it up and transport

it to MCC to decrease the temperature Time to transport milk bucket by pickup truck contractor was so long Farm owner could find a shorter route for shorter time of transport

Ice box for keep milk bags have to check temperature around 3-4 °C during transport Microorganisms also multiply from MCC to milk retailers After milk packs arrived the shop, milk always place in 3-4 °C until it was taken to pasteurization at the milk retailer, the SCP in milk were high for all seasons The pasteurization must be done in the right process to destroy pathogen in raw milk

However, the SCP in this study only a screening method to monitors milk hygiene For deeply identify microorganism, the occurrence of zoonotic bacteria in raw milk have to analyst

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