Quality/Leak questions on processed meat vacuum packages

Dear Colleagues,

I have 2 question;

1. What causes vacuum leaks in processed meat packages (even before end of shelf life; all raw materials used are in specification)

2. Gelatin forms outside the products; instead of it being blended with the product, it sort of coats the products. 

Looking forward to your responses.

Regards,

Megan

1. What causes vacuum leaks in processed meat packages (even before end of shelf life; all raw materials used are in specification)

2. Gelatin forms outside the products; instead of it being blended with the product, it sort of coats the products.

Kiind regards

Dr. Humaid Khan

Managing Director

Halal International Services

Australia

Dear Magan

1. What causes vacuum leaks in processed meat packages (even before end of shelf life; all raw materials used are in specification)

Very occasionally, meat from a pack that is dominated by lactic acid bacteria is characterised by an aroma of hydrogen sulphide that rapidly dissipates when the meat is removed from the pack. Certain isolates of Lactobacillus have been shown to produce hydrogen sulphide. If vacuum-packed meat has a pH greater than 6.0, if the storage temperature is 5-10°C, or if there is residual oxygen in the pack due to using a packing film with a high oxygen transmission rate, there may be an increased growth of spoilage bacteria such as Brochothrix thermosphacta, Shewanella putrefaciens, and psychrotrophic enterobacteria. In high pH meat, off odours may be detected when the bacterial count is just over 1 million per g at the surface. These bacteria will cause a range of off odours and off flavours, and in the case of Shewanella putrefaciens,

spoilage is indicated by a greening of the meat surface and a strong hydrogen sulphide odour (like rotten eggs). When Brochothrix is a major component of the bacterial population, the aroma is variously described as ‘cheesy’, ‘dairy like’ or ’bready’. Odours and flavours in high pH meat from spoiled vacuum packs have been described as ‘faecal’ or ‘sulphury’. Hydrogen sulphide and various other sulphur containing compounds have been detected in such meat. Enterobacter and other enterobacteria have been shown to produce these. If off odours are evident when vacuum packs are opened, selective counts of these organisms can be useful in identifying why storage problems have arisen. With the combination of low temperature, low oxygen availability and low pH, lactic acid bacteria will dominate the bacterial flora on the meat, as stated earlier. Other bacteria cannot grow or grow very poorly in these conditions and do not spoil the meat.

Dear Dr Khan,

Thank you so much for the response.  I have not observed any off odour but will certainly be on the look out for all the things you mentioned.

Dear Colleagues,

 

I have 2 question;

1. What causes vacuum leaks in processed meat packages (even before end of shelf life; all raw materials used are in specification)

2. Gelatin forms outside the products; instead of it being blended with the product, it sort of coats the products. 

 

Looking forward to your responses.

 

Regards,

 

Megan

Hi Megan,

I assume this is plastic packaging.

(1) You omitted to mention what kind of seal is involved, eg simple plastic bag or tray pack or ?

A few common causes IMEX are (a) inappropriate plastic material, (b) inappropriate sealing procedure, (c) moisture on surfaces of tray packs.

Hi Charles,

We use a plastic base and lidding, that is mechanically sealed by  a vacuum sealing machine.

Hi Charles,

 

We use a plastic base and lidding, that is mechanically sealed by  a vacuum sealing machine.

IMEX the problem was (c) but presumably could be either/both of (a,b) also.

The usual first choice for advice is either/both of the machine/lidding supplier

Thank you so much,

I will do my investigation and  see what findings we get.

I used to work with vacuum bagged meats and found that the majority of reasons for finding a bag that has lost its vacuum was due to either:

- food debris or moisture on the inside of the bags at the seal location, leaving a gap in the seal or a poor seal more likely to break, or:

- perforations in the packaging causing a tiny hole or tear and thus loss of vacuum, usually due to poor handling

Thanks,

I observed some moisture on the base and purposely added drops of water to  some package on the sealing line,  will be studying them .