Normal bacterial finding out for organic uncooked milk is ‘no longer sufficient’, eye finds
Laboratory pasteurization depend (LPC) is former to assess uncooked milk quality; this knowledge is former by some dairy producers to designate uncooked milk quality premiums paid to farmers and would possibly maybe even be former for troubleshooting bacterial contamination disorders.
LPC most continuously enumerates thermoduric bacteria – the form that will maybe withstand pasteurization – on the other hand it’s no longer identified the form of bacteria, e.g. sporeformers or non-sporeformers, would possibly maybe even be decided by simply by taking a have confidence on the LPC level.
To ascertain if LPC ranges would possibly maybe even be a trademark of the form of bacteria unique in uncooked milk, researchers from Cornell College quiet 94 organic uncooked milk samples from across the US, assessed these through LPC, and characterised the bacterial isolates.
They chanced on LPC concentrations that ranged from undetectable to 4.07 log10 cfu/mL, and 380 bacterial isolates were analyzed, with the thermoduric bacteria remoted from the samples being split in 3 groups: gram-sure sporeformers (52%), gram-sure non-sporeformers (44%) and gram-negative bacteria (2.4%).
When it involves the LPC ranges, the massive majority of samples (66) had a LPC ≤100 cfu/mL; 6 samples were with a LPC between 100 and 200 cfu/mL, and 10 samples – with a LPC ≥200 cfu/mL. Further diagnosis showed that there was as soon as an inverse trend between the proportion of gram-sure sporeformers and the LPC concentration – samples with elevated LPC had decrease proportions of gram-sure sporeformers. However that trend was as soon as no longer vital, in accordance with the analysis group.
“LPC level by myself affords no perception into the make-up of the thermoduric inhabitants in uncooked milk and extra characterization is essential to elucidate the bacterial drivers of elevated LPC in uncooked milk,” the researchers concluded.
They leveraged a microbial identification application called MALDI-TOF MS, which is purported to be more readily on hand to dairy producers than 16S rDNA PCR and sequencing.
“While our data indicated settlement between 16S and MALDI-TOF MS for 66.6% of isolates on the genus level, 24.2% and 9.2% must no longer reliably identified or were mischaracterized the utilization of MALDI-TOF, respectively,” the researchers acknowledged.
“This implies that extra optimization of this plan is essential to enable for simply characterization of thermoduric organisms ceaselessly mark in uncooked milk.
“In a roundabout plan, our eye affords a recent level of view on thermoduric bacteria selected by the LPC system and establishes that the LPC by myself is no longer sufficient for identifying the bacterial drivers of LPC ranges. Further pattern of immediate characterization solutions that are accessible to producers, cooperatives, and processors will make stronger milk quality troubleshooting efforts and within the end give a boost to outcomes for dairy industry community contributors.”
Source:
Troubleshooting excessive laboratory pasteurization counts in organic uncooked milk requires characterization of dominant thermoduric bacteria, which involves non-sporeformers moreover to sporeformers
Authors: Lee, T. R., et al
Printed: Journal of Dairy Science, 20 January 2024
DOI: 10.3168/jds.2023-24330
