Headline hype isn’t science: ‘Avocado can prevent Listeria in food’

High standards regarding Listeria monocytogenes control and consumer demands for food products without synthetic additives represent a challenge to food industry. We determined the antilisterial properties of an enriched acetogenin extract (EAE) from avocado seed, compared it to two commercial antimicrobials (one enriched in avocado acetogenins), and tested purified molecules.

avocado-pair-cob_16Acetogenin composition in pulp and seed of Hass avocado was quantified. EAE were obtained by two sequential centrifuge partition chromatography separations and molecules purified by preparative chromatography and quantified by HPLC-MS-TOF and HPLC-PDA. Avocado seed extracts which are the following two: 1) EAE and 2) the commercially available antimicrobial Avosafe®, presented similar inhibition zones and chemical profiles. Minimum inhibitory concentration (MIC) values of extracts and two isolated acetogenins varied between 7.8 and 15.6 mg/L, were effective at 37 and 4 °C, and showed a bactericidal effect probably caused by increased membrane permeability and lytic effects, evidenced by flow cytometry at 10 and 100× MIC. Activity was comparable to Mirenat®. Most potent acetogenins were Persenone C (5) and A (6), and AcO-avocadenyne (1), the latter exclusively present in seed. Common features of bioactive molecules were the acetyl moiety and multiple unsaturations (2 to 3) in the aliphatic chain, some persenones also featured a trans-enone group. Seeds contained 1.6 times higher levels of acetogenins than pulp (5048.1 ± 575.5 and 3107.0 ± 207.2 mg/kg fresh weight, respectively), and total content in pulp was 199 to 398 times higher than MIC values.

Therefore, acetogenin levels potentially consumed by humans are higher than inhibitory concentrations. Results document properties of avocado seed acetogenins as natural antilisterial food additives.

Inhibitory activity of avocado seed fatty acid derivatives (acetogenins) against Listeria monocytogenes

Journal of Food Science, 21 November 2016, DOI: 10.1111/1750-3841.13553


Avocado vomit tales and Listeria

I don’t like avocados.

There was this one time my ex-wife made an avocado dip to take to my relatives and was so drunk or hungover she barfed up all this green garlicly stuff at the side of highway 400, headed to Barrie.

guacamoleIt smelled awful.

Maybe she had Listeria (doubtful).

Listeria monocytogenes can grow and multiply in various food matrices and cause severe human illness. Apart from the influence on consumer health, L. monocytogenes contamination of ready-to-eat (RTE) food products causes major economic losses due to product recalls.

Control of foodborne pathogens in RTE food products is a challenge, specifically in foods that cannot undergo a heat-treatment during processing. The aim of this study was to develop control strategies for the management of L. monocytogenes in an avocado processing facility, additional to a quality control system. An in-house monitoring system (IMS) was established to test specifically for Listeria spp. in the final products and processing environment, including floors, equipment, work areas and personnel. Guacamole and environmental samples were collected and tested on-site for Listeria with the ISO 11290-1 method.

Based on the prevalence of Listeria, the facility introduced new strategies in processing to counter cross contamination. Results from the 2014 guacamole production season showed almost complete eradication of Listeria spp. in final products (0.17%, n = 1170) and the processing facility (0.79%, n = 1520). This is a major achievement since the highest incidence of Listeria spp. over a period of five years was measured at 11.39% (n = 948) in the final product during the 2013 season and 13.44% (n = 1927) in the processing facility in 2011.

These results indicate that successful management of Listeria spp. in an avocado processing facility can be accomplished with in-house monitoring of the listerial population and subsequent adjustments to the processing system.

So it probably wasn’t Listeria. Just booze.

Successful management of Listeria spp. in an avocado processing facility

Food Control, Volume 62, April 2016, Pages 208–215

Amy Strydom, René Vorster, Pieter A. Gouws, R. Corli Witthuhn



Look for listeria, it shows up; avocado from Peru recalled

 Fine Mexican Food Products, Inc. (FMP), located in the City of Ontario in California, is recalling 1,423 Cases of 12/2 lb. Frozen Avocado Pulp and 1,820 Cases IQF 8/3 lb. IQF Avocado Halves as distributed since June/2010 because of the possibility to be contaminated with Listeria monocytogenes.

Frozen avocado pulp and IQF avocado halves were distributed to distributors in California since June 2010.

These 2 products are identified as FMP white label on the corrugated shipping carton and pack size is 2.2 lb. /bag 12 per shipping carton and Product code 00115 for Frozen Avocado Pulp.

Pack size is 3 lb. /bag 8 bags per shipping carton and Product Code 00131 for 3 lb. IQF Avocado Halves respectively with expiration dates of June/July/August 2012.

There have been no reports of illness related to the products.